Break Though in Hydrogen Storage - Ammonia Borane

Watts Up With That has a post on Hydrogen Getting the Dynamite Treatment. As with most break through reports, I take this with a grain of salt. Once cost estimate start rolling in, then I can get more serious.

The ammonia borane storage could have a fairly large safety impact as much psychological as real. Hydrogen explosions when properly contained are pretty destructive, but most motor vehicle crashes don't create great conditions for an optimum explosion. If you have ever seen the Hindenburg film, you have an idea of what happens. Under pressure a hydrogen leak will burn like a torch until the temperature of the tank rises enough for a rupture. Then you can get a pretty good bang similar to cooking off a propane tank. The biggest difference between propane and hydrogen is hydrogen has a larger range of combustion concentrations. Energy wise, hydrogen is pretty so so.

Psychologically, this may kick interest in hydrogen in the butt. Overcoming irrational fears seems to be the trick with any energy use now a days.

Since I am on the alternate energy subject, Nanosolar has an agreement with Belectric which used to be Beck Electric. Belectric is a big time installer of photovoltaic energy farms. This can be a big boost for Nanosolar and solar in general, but on a utility scale. Residential scale is my biggest interest because it is the way to go for personal energy independence. Utility scale PV is still a warm and fuzzy experiment and not a great investment without government subsidies. Cost effective PV on small scale makes much more sense economically and aesthetically.

I still haven't gotten around to building my prototype electrolyzer. I have had a few ideas on how to increase the operating pressure - safely. I don't want to build something that will blow up on me unless I want it to. It is still in the works though, stay tuned.

Political Climate Change

Allegations of corruption are again making news in the Climate Change debate. A press release for a not yet published report made a claim that 80% of global energy could come from sustainable energy sources IF political will focused on that goal.

Whoop d friggin' do!

The lead author of the now published report is a bigwig with Greenpeace and the report list a variety of scenarios, one of with is a maximum possible sustainable energy percentage by 2050. So does this indicate a conflict of interest?

Of course, but what should you expect? Like it or not, the real world of politics is not all warm and fuzzy idealism. The social mores of the undeveloped nations is not the same as the developed nations which is not the same for all the developed nations. That is the way it is, has been and will continue to be. Working within the system with its imperfections is a political exercise. Science, well, would best be apolitical. It is not though. Scientists carry social baggage just like the rest of us. Intellectuals have much more baggage because their idealized views of a perfect world are unattainable because man is imperfect. There is a great deal of frustration for all to share.

Perfectionists are constantly disappointed while pessimists are often pleasantly surprised. A realist is a pessimist with hope. When it comes to policy, realists should be in charge.

The realist recognizes that good enough for now, not perfect solutions, are always required in an imperfect world. My focus in this blog changes with the general political opinions which drive transitions to hydrogen technologies. Hydrogen is not perfect, it has several issues that are challenging, but not insurmountable. I am a fan of hydrogen because it has awesome potential for not only national energy independence, but personal energy independence. That, the potential for personal energy independence, is one of hydrogen's largest obstacles. The ability to make your own fuel from less than perfect energy sources can create serious political problems for those wishing to financially control the masses.

That may sound like a paranoid conspiracy mentality, but there is plenty of basic truth in its foundation. Without sustainable profit for governments and industry, there is no political motivation for home brewed anything. For that reason, the components scaled for home production of hydrogen have taken a turn to industrial scale components. Hydrogen made from reformed natural gas is taxable because natural gas production and distribution is controllable. The US Department of Transportation research into hydrogen is focused on larger scale, taxable plant sizes. That is the way of the world.

Once you allow for the independence afforded by home brewed hydrogen from water, the cost and efficiency factors become more flexible. Fifty percent overall efficiency is more than acceptable for home brewer desiring a self directed lifestyle. For the Government, 50% is unacceptable, even though 33 percent has been more than acceptable for other energy sources in the past. This is a humorous conundrum.

Perspective?

The world is a whacky place. Everyone has an opinion and with the internet you can hear everyone's. There is a lot of silly crap on the internet. I am sure many think the things on this blog are crap. Crap, I guess is in the eye of the surfer.

The chart above is for GISS Temp Global Temperature anomaly from 1880 to 2010. I plot the overall trend in blue, the trend from 1950 to present in red and the trend from 1999 to present in yellow. The Y axis is actually in hundredths of a degree, even though it says 120, it is really 1.2 degrees above the average which looks to be around 1950ish. I plotted the trend from 1950 because that is when CO2 is supposed to have overtaken natural forces. The trend from 1999 is just because I had plotted the RSS trend from that date.

With the trends plotted this way you get the impression that warming is accelerating. That is the perspective of the global warming advocates. GISS (Goddard Institute of Space Studies) Temp is the warmest of the big three global temperature averages. It is the warmest because of the way they average the missing data around the North Pole. I believe they do the same thing with the South Pole, but since the averaging at the South Pole doesn't add too much to the overall average it is not a big issue.

The poles, in all the averages, are the coldest place on Earth and are not included in as "real" data. Some of the averages guesstimate, some don't, but the coverage is very poor. The Northern hemisphere land areas are very well represented in all the averages. The ocean coverage is pretty sparse. All of the averages agree well, but there is some controversy about how good Global Temperature Average is for much of anything.

I tend to go with the satellite data, mainly, because I am interested in the Tropopause, which is THE coldest place on Earth, it just isn't on Earth, it is above the surface. Many of the lukewarmers and skeptics use the satellite data, especially the UAH data, because it doesn't show as much warming. The warmers tend to prefer the surface station data. Why do the different groups pick different data sets? Because of their perspectives.

Personally, I don't have a serious agenda driven perspective of climate change. I do have, in my opinion, a perspective of bullshit! Choosing your data to amplify your agenda is bullshit. That is what people do though, choose their bullshit and defend it until it embarrasses them. What is really weird though, is people that don't have a clue, will ally themselves with some one else's bullshit and defend it like it was their own.

I pick on the tree hugging environmentalists a lot because they make the silliest mistakes trying to defend the bullshit they don't understand. The conservatives are more real world, if they don't understand it they just say so and that they trust so and so more than the other asshole.

Take the nuclear situation in Japan. There are still a bunch of the environmental types preaching gloom and doom because of the fallout. The situation is by no means great, but it is nothing as bad as the gloom and doomers say it is. I just read a report today that stated that just recently, people are exposed to more radiation from medical care than normal background radiation. It was in the New York Times of all places. Most of the gloom and doomers would not know a Becquerel if it bit them in the ass. That doesn't stop them from explaining in great detail how terrible 15 Bq/M2 is, how it will mutate your children and probably turn your Chihuahua in the Cujo. Radiation is something we live with every day, it is scary, but so is driving through Miami during rush hour.

The reason I started this blog was to try and post some real information on alternate fuels. Since I started, a lot of things that seemed promising have fallen by the wayside. Some because the promise they held turned out to not be so promising. Some because the perspective of the public has changed. This also is very human. It also leads us to making the same mistakes over and over again.

We have been through this fuel crunch before. The politicians made the same promises. They didn't pan out because things seemed to get better. So we are right back where we started. There is something a little different this time. There is the real potential to free ourselves from dependance on foreign oil.

Not everyone can do this right now. There are still a few issues to be iron out, but it is possible. While I am still trying to bring a few parts of the puzzle together, hydrogen has serious potential that can be realized.

The Home Hydrogen units are being dropped in favor for larger industrial scale systems or cheap fossil fuel reforming systems. Nanosolar, the maker of not great efficiency, but reasonable priced photovoltaic solar cells, seem to have come up with the right idea. Reliable, realistically priced energy is more important than cheap addictive energy or high efficiency unaffordable energy. With proper planning, home brewed power at twice the cost can be the bigger savings. Why, because we cannot count on the cheap energy we are addicted to.

The one big issue is the matter of scale. The home brewed system is a bit scary. It is a hard sell to get people to commit to a fairly large investment to get off the grid. With a reasonable priced home hydrogen generator, the sell will get easier. So I am going to focus more of my time on either designing a home brew system, which is not that difficult, or finding an existing system that fills the bill.

The compressor I mentioned before is a fairly large issue. That silly Shoe Box compressor has surprising potential. I would still prefer a Diaphragm compressor for safety and efficiency, but the cost needs to drop, which will not happen until a viable home market appears. More on this soon.

The electrolyzer looks easier than I expected. I still need to figure out a better case design to allow higher pressure, but PVC cells inside a water jacket to control heat, looks promising. The silly guys playing with Brown's gas actually had a few good ideas that just need tweaking. So I will start posting a few off the wall ideas for designs I may get around to testing.

Where is the Future?

Blue - 1979 to 1998 Red - 1979 to 2011 Yellow - 1999 to 2011

While still playing with the opensource charts, I made this one of the RSS global surface temperature data. There is nothing really special about RSS, it just is a smaller data file that is easier to play with. The linear regression for the three plots extends to the year 2100 (2097 actually, I set the scale so that 1998 shows up better.)

My main thing with this blog is hydrogen and alternate energy. The only reason I have any of these climate charts and other climate stuff posted, is that climate change, aka global warming, is one of the reasons hydrogen as a transportation fuel is being considered. Except for saving the planet, hydrogen is pretty limited in most cases. It is costly to develop and risky to use.

More people using hydrogen drives the cost for electrolysers, fuel cells and storage mediums down. Without mass production, hydrogen for residential power storage is just an expensive hobby. The data in the above chart shows why entrepreneurial hydrogen use and production development is lagging. Governments can do a lot to compel citizens to use certain products. Governments though are inefficient. Entrepreneurs, are the real drivers of any capitalistic country. The entrepreneurs that make the best products are smart enough to know when to pull the trigger. The above chart scares the alternate energy guys to death.

The chart indicates the drastic impact of human caused global warming is greatly over estimated. The chart doesn't prove anything, it just is an indication that climate change is not an immediate concern. Without an immediate concern, the entrepreneurs that are investing their own money or reputations are not ready for the risk. There are still niche markets, but they seriously limit the potential profits. Too many players for not, what appears to be, a rapidly expanding market.

Ballard Power and their partner Plug Power have a decent niche which could be some what rapidly expanding. The new battery cars, Chevy Volt for example, have serious limitations. 30 miles to a charge will not appeal to a very wide customer base. It is basically a toy for the wantabe green crowd and government motor pools. The general American public wants a car that gets at least a 200 mile range, is bigger which is assumed to be safer and convenient refueling. Ballard Power's FC Velocity fuel cell for use in material handling is a good upgrade for the Volt battery pack. Even with the cumbersome fuel storage tanks for compressed hydrogen, a Ballard Power upgrade can deliver the 200 mile range and peppy performance. Refilling though is still an issue limiting the potential of the upgraded Volt.

I mentioned before that the Honda Home Hydrogen station was a natural gas reforming unit. Molten Salt fuel cells are designed to run on natural gas, natural gas and propane are much easier to locate now for refueling, so why bother with the Proton Exchange Membrane fuel cell manufactured by Ballard if you have no access to inexpensive refueling? None really.

A molten salt fuel cell for a vehicle is a little more complicated than the PEM. While the molten salt fuel cell generates electricity it generate a lot more heat. That heat, which is a high temperatures (over 500 C) would require co-generation to dissipate the heat and generate more of something while it is at it. A small gas turbine driven generator is the most likely co-generation. Depending on the temperature range and heat available, a turbine using say a refrigerant for its gas, could generate electricity using the waste heat of the natural gas fuel cell. It is entirely doable, but the extra complexity means higher initial cost, more risk for the consumer and higher maintenance cost. So doable or not, it ain't likely to happen. This goes right back to the matter of scale, utilities with government subsidies may give it a go, but consumers needing a cost effective alternative will still be screwed. Without a hydrogen infrastructure, the Volt, Ballard Power and my dreams of a hydrogen RV are dead.

The Home Hydrogen Stations I was counting on could cost less than $4000 with over 100,000 units per year production and less than $2500 a year with 250,000 plus units per year. Manufacturing scale is a really big deal. Right now, you would be lucky to find a high pressure, water splitting home unit for less than $50,000 dollars. If the greens really wanted to put their money where their mouth is, they should be more involved in strengthen this weak link.

There are a number of low pressure PEM based electrolysers that can be used with extra value added design to make home refueling units. Then, low pressure hydrogen production is not exactly rocket science. Dangerous Laboratory's design looks complicated, but that can be tighten up fairly easily. Also, some of the idiots playing with HHO or Brown's gas aka Oxyhydrogen, have some homemade systems that could be modified to produce reasonable quality hydrogen. It is all in separating the anode gas O2 from the cathode gas H2. A fairly easily made plastic part could separate the gas streams. Porous nickle anodes and cathodes with an alkaline electrolyte (KOH) can produce lots of hydrogen reasonably inexpensively.

What is reasonable inexpensive depends on you power source and your needs. Wanting the highest efficiency is admirable, but getting the job done with affordability is the ticket. In the island home example, forty percent efficient is more than acceptable. After spending $10,000 for a 10 KW solar array another $10,000 for storing energy in not a big deal. The cost for gge (gasoline equivalent gallon) can be over $6, but in the island house case, transporting, storing and convenience are worth it when gasoline is damn near $5 a gallon at the fuel dock now. I can make the same case for the RV of the future. No way can I do it for the Tahoe FCV.

Interestingly, with the Island Home or the RV of the Future, I may be able to make a case for a FCV boat or a FCV convenience vehicle for the RV. More likely, a hydrogen fueled Internal Combustion Engine (ICE) would be better despite the lower efficiency.

So now the focus needs to be on reasonably affordable hydrogen production. Since we need pressurized hydrogen, the compressor is the one component that has to be absolutely right. I am fairly confident that the metal diaphragm pump will prove to be the best for overall safety and efficiency.

A multistage diaphragm pump doesn't have a lot of moving parts. Reed valves direct the gas flow and are not very complicated. The diaphragms are flexed by a rotational motor shaft with cam lobes. That is about it, the cam lobes push on the center of the metal diaphragm to displace the gas volume forcing the gas out of the discharge reed valve while the intake reed is forced closed. When the diaphragm relaxes, the discharge reed closes and the lower pressure opens the intake reed valves. The discharge of a lower stage is piped to the intake of the next stage. Simple and elegant design with no piston rings or lubrication required in the gas stream. Just to make the pump last longer, teflon coated metal diaphragms would be nice. The teflon would absorb the energy of the tiny hydrogen molecules reducing damage to the metal diaphragm. The cams and motor shaft can be lubricated outside of the gas stream or oil free shaft to cam surfaces can be used. A non-sparking electric motor adds to the cost, but not significantly. The motor can be either really beefy for higher flow, higher pressure, or not so beefy for low flow, medium pressure. The cost of the storage tanks is a limiting factor. 4500 to 5000 psi is the maximum cost effective pressure currently for storage, with the 3000 psi range considerably more affordable.

The 3000 psi range for storage also extends the life of the unlined storage tanks. Aluminum cylinders (tanks) have a burst pressure nearly twice the 3000 psi range. So the wall thickness is great enough to handle the constant bombardment of the active little hydrogen atoms at medium pressure for a reasonable number of years. As a guesstimate, approximately ten years, so figure eight years to allow a safety margin.

For the Island Home, the size of the electrolyser is not very important. It is more important for the RV of the future. Considering that, I will start looking at electrolysers designed for 4 kw input power (the rough size of the RV of the Future solar array) and a total space required of 4 cubic feet. A target efficiency of 50% will be used but after all the what ifs, 30% to 50% will probably be enough to justify the design.

That 30% to 50% range will drive most mechanical engineers nuts. After conversion to useful energy, the actual system efficiency would only be 15% to 40%. They can handle the 40%, but 15% they would laugh at. Remember though, we are using fixed cost solar energy. Any power not used is lost, so recovering 15% of something wasted can be a big deal. We have to compare the initial cost, weight, maintenance cost and replacement cost of batteries plus the cost of energy conversion from stored battery energy to useful work. Some of the work we may want, transportation, is a key factor.

So I am off to research affordable ways to make hydrogen under medium pressure. I have seen a lot of websites with big promises, but are there any that really have the goods? With a $10,000 budget and $6 gge goal, let's see if it is doable today.

Our Hydrogen Home - Is it Worth it?

An energy self contained home is the dream of many. Living in the islands of the Florida Keys, I know of several islands that have no connection to the main electrical power grid. Some of the home owners of the electrically remote island homes are very wealthy, others not so much. They deal with their power needs differently based on their financially situations. Hmmm, kinda like nations have to.

Alternate energy is a matter of cost and convenience. The less cash you have, the more inconvenience you can deal with. I like to look at the true cost for an energy self contained home (or Recreational Vehicle) every few years to see how things are shaping up. Wind and solar are the main energies chosen by the Island guys with Internal Combustion (ICE) Generators as backup. They all have to have backup generators because, they cannot store enough energy when the wind or sun is working to cover times they need energy. That adds significantly to the cost. Very significantly as fuel costs are over $3.75 a gallon. Fuel was less than a dollar a gallon when most of the island home energy systems were installed.

Because on building height limits, the massive, tall wind turbines are out of the question. This is an island tourist destination after all. Not creating an eyesore is important. Some of the older hydrogen home built in the past decade have nearly a dozen large propane style storage tanks, which are not only potential eyesores, they tend to float away in hurricane flooding. That is an expensive and potentially dangerous problem. The hurricane winds also tend to relocate wind generators.

As you can see, there are issues involved in designing an energy self sufficient tropical home. Even more if that home is to be a sustainable energy self sufficient home.

Learning from the screw ups of others is a lot cheaper than learning through your own screw ups. There is no way to avoid screwing up, but you can endeavor (I like that word)to minimize your screw ups and their magnitude.

Storage of energy is the big problem. Batteries are expensive, require maintenance and can be dangerous. While having some batteries is unavoidable, you want to get the right balance between cost, longevity, maintenance cost and safety. The telephone companies seem to have hit on the best battery storage ideas. They use massive 1.5 volt cells connected in series and parallel to provide the DC power they need. A compromise for residential consumers are large 4 and 6 volt lead acid batteries. Big banks of lithium ion sound great, but cost is prohibitive. Also, do it yourself installation and maintenance can be more dangerous. The 6 volts are cheapest initially, but specialty 4 volt batteries are a better choice. The four volt batteries have a warranted life of ten years and can last longer if properly maintained. Maintenance is pretty easy, just maintain water levels with deionized water and keep the connections clean. Any isolated island home should have three, required for the basic 12 volt systems that are less expensive. The high quality lead acid batteries would store nearly 15 kwh of energy at a cost of about $3000 USD. Medium quality 6 volts would require a bank of six batteries, $1300 USD worth, for about half the kwh and a quarter to about a half of the life expectancy, depending on use and maintenance. The lower capacity of the 6 volt batteries increases the chance of draw downs that limit the life. With batteries you basically get what you pay for, so I would not recommend a bigger bank of the six volts unless you get a killer warranty.

Hydrogen is by far a superior energy storage (battery if you will) medium. Hydrogen, because of cost, has not been used much in the Keys. That is starting to change. Home hydrogen electrolysers have not only started to drop in price, most offer something very nice, pressurized hydrogen. Compressing hydrogen in the past has been a big issue. The newer electrolysers produce decent amounts of hydrogen at a variety of pressures. Ultra high pressure, 5,000 to 10,000 psi, is ideal, but expensive. High pressure, up to 2,900 psi, is more affordable. Hydrogen is a small active atom that tends to want to be free. That puts some interesting, but not too complicated, problems on the table for storage. Soft materials absorb the energy of the hydrogen bouncing around where hard materials tend to get micro fractures fighting with the hydrogen. Luckily, steel or aluminum tanks can be internally coated with high density plastic to have both soft absorption and hard strength. The larger tanks or bottles are rated for 4500 psi which is fine for the 2900 psi electrolyser with some room for extra compression.

There are plenty of hydrogen electrolyser system manufacturers. Most are very proud of their products, meaning they are expensive. There are advantages to the higher cost systems. They are completely self contained with all the bells and whistles for those that just want a working system without the design headaches. HySTAT, has complete systems for off grid power using solar and/or wind if you have the cash. Their systems have a fairly good size foot print. Being self-contained, you have to be able to live with that. Mix and match systems offer more flexibility with of course more headaches, which I am now exploring. The price is pretty frightening too, which sends me into do it yourself mode.

The plumbing of the tanks, since it will take several to store enough hydrogen, will require either more expensive material or more frequent maintenance. Stainless steel, is a fairly soft metal, which is a good trade off between maintenance cost and initial cost. You can go into any dive shop and see air fill storage tanks with manifolds that look like what you would need for home hydrogen storage, the only difference is that it is a good idea to have the tanks lined with plastic.

Lining the tanks with plastic is pretty simple if you have the equipment. A process called rotational molding can coat the inside of the tanks by putting powered plastic inside the bottles then heating the bottles while slowly rotating the bottles in all directions to uniformly melt the plastic, forming a uniform layer inside the bottles. It is a little pricey, but more than doubles the life of the fairly expensive tanks. So this headache is not to hard to cure if you have space for low pressure storage.

You need to first be able to make the hydrogen and then use it. To make the hydrogen you need water, an electrolyser and power. The self-contained, higher price systems use any combination of electrolyser pressure and/or compressors. Every component added is an extra headache. Home hydrogen fueling systems, can reduce some of that headache. Designed to refuel hydrogen vehicles, more forklifts that on the road vehicles right now, they produce hydrogen at the pressure you need, approximately 5000 psi. To avoid warranty issues, the storage system would have to be manually filled.

Honda Motors has a pretty good idea. The Honda Home Energy Station, uses waste heat for home hot water heating and provide backup power. Unfortunately, it generates hydrogen from natural gas. Which is kinda stupid, since fuel cells can run off natural gas to begin with.

Low pressure hydrogen with compression is still an option. Looking back at the the first solar powered home, Mike has 10 1000 gallon propane tanks to store about forty gallons worth of gasoline equivalent hydrogen gas at 200 psi. Living in the country with not many neighbors, Mike can get away with this. Mike also has one hellava expensive system that is like a Rube Goldburg design based on what we need. The electrolyser he has is pretty much what we need though.

Building from scratch, like Dangerous Laboratories, is not for most folks. Cal State University built a hydrogen filling station that has a few good ideas worth looking into. this requires learning that 1 kilogram of hydrogen would occupy 11 cubic meters of space. All the hydrogen generators list production in Nm3/hr, which is Normal cubic meter per hour. Normal meaning Standard Temperature and Pressure (STP). One low pressure hydrogen electrolyser, the M2-EL2500-12.5, produces 0.83 Nm3/hr @ 60 PSI requiring 2500 Watts/hr. That would be 1 kg-H per 13 hours, just under 2 kg-H per day. Since we are planning a 12 volt system, that is a good choice. Production could be doubled by using two or doubling the voltage and using the M2-EL2500-25. At 60 PSI we would need to compress to around 4000 PSI. Hydrogen compressors are a little special. Hydrogen is an energetic molecule in more than one way. Being the tiniest of molecules, it is hard to contain. When it is not contained properly, it tends to cause explosions. We don't want that, so a compressor specifically rated for hydrogen is what we want. Hydropak makes low pressure compressors we need, unfortunately, their main website is in Turkish.

Converting the hydrogen into the power you want has three options; burning like propane, running a motor for a generator etc. or using a fuel cell for conversion to electricity. For the island home, the motor as in running a generator is the easy, cheap way to go. That is fine for a place that is not occupied all the time. The motor for the generator will need oil changes and maintenance just like any gas power motor. Other than aggravation, the generator simplifies things quite a bit. All the basic use for the generator would be for high load things like air conditioning and back up charging of the batteries if there is a high demand. A fairly inexpensive inverter can be used for 120 volt electric with the batteries providing power. Shopping wisely can reduce the demand of 120 volts appliances. This is very similar to most of the island off grid designs, the only difference is storing energy as hydrogen rather than buying more batteries.

Using a hydrogen fuel cell is another option. Ballard Power makes a home hydrogen fuel cell designed for 2Kw backup power system for $2600 USD. Two kw gives you 18 amps at 110 volts AC. Enough for most of the basic stuff. For air conditioning, a little known option is a natural gas drive condensing unit. The Trane Company used to make a condensing unit for air conditioning with a natural gas powered motor driving the compressor. It looks like that design has passed away, but the idea is good for the island home. Here you can just match a hydrogen gas driven generator when there is a need for cooling. Beefing up the fuel cell and inverters is always a possibility if you have the cash.

Ballard also makes a 20Kw fuel cell for $10,000. This is about the lowest cost per kw of any fuel cell on the market thanks to mass production for the materials handling industry. This would require a bit more controls than the other units and better consideration of the DC voltage range of the overall design.

This brings us to solar cells. Since the 12volt system is the standard for most solar residential applications, that is what we would most likely go with, unless we opted for the larger 20 kw fuel cell. In that case matching voltage ranges for the fuel cell and solar panel array makes more sense. This would also require another look at the hydrogen electrolyser input voltage. We only want to make hydrogen from "free" energy, that in this case is the solar panel array. Finally, the amount of hydrogen storage would depend on that decision as well.

Adequate hydrogen storage depends on demand and replenishment rate. Compressed hydrogen makes the space required more tolerable. At 2900 PSI, the space required is a lot less than the 200 PSI Mike used in his video. There are a variety of manufacturers of suitable storage tanks. They do not have the plastic liner, that you would have to arraign on your own at a rotational molding facility. Not lined will do, they just need to be inspected annually and may require replacement in five years or so. All the plumbing should be inspected annually. Being able to buy a ready made system would be great if you have the bucks, but they seem to be going out of business pretty regularly. If you have ever been to a dive shop to get a cylinder refilled, that is the basic system you want. A good compressor that doesn't contaminate breathing air will work and the tank manifold is rated for 4500 psi in most cases.

These 200 bar storage and compression systems are not cheap. You will be looking at $5000 USD easy. Home CNG, Compressed Natural Gas systems will work also. The price is about the same once you add the storage. There are a couple things you need to know now. First, I am not responsible if you blow your silly ass up. This is a do it yourself thing. Second, with reasonable precautions this system will work fine.

The first precaution is remembering that hydrogen is an energetic gas. At some time there will be leakage, you don't want that leakage to build up where it can go boom. A nice open detached shed should be the hydrogen system home. You can screen the shed in and cover it with tasteful looking lathe to make it look like a tiki bar, but don't box it in. Second, think valves, lots of high quality valves. Things break and you need to be able to isolate the broken things. Third, you need a low pressure tank for the electrolyser output which the compressor can then boost to pressure in the storage system.

A fairly good size propane tank can serve as the discharge tank for the low pressure electrolyser. The output pressure of a low pressure electrolyser is about 60 PSI. The volume of this tank just determines how often your expensive boost compressor runs. I would recommend a 100 pound propane tank as a minimum for a small compressor with a hundred gallon propane tank not a bad choice if you have the room. If you use a medium pressure electrolyser up to 200 psi, either of these tanks will be fine. More than that pressure, you can can the compressor and size the storage tanks for the pressure and volume you need. Right now, the low pressure electrolysers are cheap enough to justify the five grand for compressor and higher pressure storage. Remember, that the price is dropping on some of the home refueling systems, so this stage may soon not be needed, other than storage.

The low pressure electrolyser I selected above only makes about 1 kilogram a day on a good day. One kilogram is about 33 kilowatt hours of energy. So if you use the generator only design, you get about 1/3 of that as useful energy or 10 kilowatt hours because of engine efficiency. With a fuel cell you get nearly 2/3 or 20 kilowatt hours out of one kilogram of hydrogen. So unless you are a party hardy energy hog, you really don't need that much storage. Mike in the video had ten 1000 gallon propane tanks at 200 psi that only held 40 kilograms of hydrogen. One of the standard 5 foot tall air cylinders has a volume of about 2700 cubic inches or 1.6 cubic feet which is equal to about 12 gallons. At 3000 psi, the energy density of hydrogen is roughly 1900 watts per gallon, so each tank would hold roughly 20 KWh which is close to 2/3 kilogram of hydrogen. So 10 eight inch round by 55 inch tall cylinders at 2900 psi will hold 200 kwh of gross energy, about 6 kilograms of hydrogen.

1900 watts per gallon at 3000 psi is a good number to remember. That is not a lot of energy per unit volume. Also remember hydrogen likes to leak. The choice of high quality valves and plumbing is important. Lining the tanks with plastic helps reduce leakage, high density plastic or Teflon(r)seals all are important considerations. Ventilation as I said is a must. Hydrogen flashes in concentrations for 4% to 75% by volume. The number of connections with a ten tank storage system is about as much as I would even think about. Any more and larger high pressure tanks are definitely worth the extra money.

Using the 20kwh per tank we can start completing our design. With the generator only system we would get about 6.7 kw hours per tank. On a good sunny day, the cheap electrolyser would come close to refilling the tank. As long as you are not an energy hog, that is not bad. Remember, most cooling is required when you have the most sun. So the solar panels can take up a good deal of the air conditioning slack. With the hybrid system, the 2kwh fuel cell would deliver nearly 12 kwh per tank because of its higher efficiency. Depending on use, the air conditioning dedicated generator drop the kwh per tank towards the 6.7 number. With the more expensive larger fuel cell, you would stay near the 12 kw number. This makes a big difference in the number of tanks needed for storage. With the bigger fuel cell, three or four tanks should be plenty. Six for the hybrid system. These configurations would give you about two low to nearly no solar energy days of backup. Since the generator really doesn't care if it has hydrogen, propane or regular gasoline, the hybrid and stand alone generator system (both can charge the battery back while running) gives you a plenty of backup.

Cheating up to 4500 PSI is an option with the right tank system. That would increase the storage per tank to 31 kwh or very nearly one kilogram per tank. Remember each tank is 12 cubic feet of volume. The higher pressure would increase leakage and decrease the life of the unlined tanks. So the cheating up should only be for a short term occupied mode with the 2900 psi the normal unoccupied storage mode. I will have to double check, but the leakage at 4500 PSI is the squared ratio of the pressure change. So there would be 55% more leakage at the higher pressure. Nominal leakage at 2900 psi is only about 0.05% per day, livable. At the higher pressure, the pump should be the weak leakage link which may require solenoid operated isolation valves to protect the pump when not running. While 55% more of a small number doesn't sound like much, damaging the expensive pump would not be a nice thing.

While I am a big fan of hydrogen only, for the island off grid house, I would go with the hybrid system with either gas or propane as a backup energy source. That being the case, a 4 to 6 kw solar array is all that is required. That will provide enough energy for the electrolyser and battery charging with basic high solar conditions covering most of the needed daily electric, refrigerator and lighting. With expected higher air conditioning use, a larger 8 to 10 kw array should be considered. Nanosolar has the lowest cost per Watt at $1 USD, unfortunately, they are not for sale to the general public yet. Most panels currently available are close to $2 USD per Watt. That would tend to bring the budget mined down to 3 kw for the minimum array size. At 3 kw you can still generate hydrogen (2.5 kw per kilogram) and maintain battery charging if you are careful.

If you have been following my fantasy hydrogen designs, you may notice a few changes. One is the the 200 bar home electrolyser for $2300 USD. The only one using water as a source is kaput. Also the Honda Phill, which was a compressed natural gas system, which could compress and store hydrogen in a pinch, is also kaput. As mentioned earlier, the Honda home fill system is a natural gas reformer, not suited to the the off grid Island Design. This is making me take a new look at Dangerous Laboratories. Making hydrogen from water is a piece of cake. Separating the hydrogen from the oxygen produced is the trick. There are several low pressure PEM electrolyser designs, but you real don't need a PEM to make hydrogen. The second change is storage. Without the less expensive home electrolysers that can produce the higher 3000 to 5000 PSI, that increases storage space yet again. There are some tricks there I am researching. It seems that only Ballard Power is sticking to their game plan and staying solvent financially with their materials handling angle.

For the hydrogen compressor, I am pretty sure a metallic diaphragm two stage compressor will fill the bill. The solid metallic diaphragm is a natural protection for the pump in case of high pressure leakage. Being oil free, the diaphragm design is also likely to have a longer life. I just have to locate one that is small enough for a home application that doesn't have the medical gas compressor cost. That will bring everything back to being viable again. I'll be back to this when I find out.

What's Going On?

Things move at a snail's pace in the Hydrogen Economy world. While I am toying with potential ideas for hydrogen fuel cell vehicle I would like to see, most of the real focus is on battery cars and battery hybrids. I did notice that Plug Power is working on a joint venture to incorporate a hydrogen reformer in a Hybrid of a Hybrid design.

Storage of hydrogen and access to hydrogen are the major problems with hydrogen FCV. Plug Power's idea is to reform petroleum to make the hydrogen for a FCV. This would kill both problems with on stone. Normal filling stations would provide the hydrogen in the form of petrol, waste heat from the fuel cell would provide part of the reformer energy needed, and you would make your own hydrogen while tooling down the road. Storing hydrogen as liquid fuel greatly reduces the storage demands.

The question would be the overall efficiency. Reforming petroleum is more efficient and less energy intensive than splitting water. Fuel cell are more efficient that internal combustion engines(ICE). The average efficiency of an ICE is in the neighborhood of 25% for the vehicles that the Hydrid Hybrid would be competing with. So if the improvement in efficiency is to 50%, then the Reforming FCV could be a good deal. There is still costs versus performance, so who knows. This joint venture with Exxon Mobile and a few others started in 2007. It is about time for something to break one way or the other. Check out Plug Power for more information.

The on the road hydrogen reformer by itself doesn't blow much wind up "Green" skirts, it is still using fossil fuels, just maybe more efficiently. It could open more doors though. Synfuels tailored for maximum hydrogen content could be interesting. Some hydrogen storage system use solid hydrides which when heated release their hydrogen for use. Liquid equivalents could be pumped into the tank, reformed and the basic hydrogen bonding chemicals potentially recycled. The more complexity involved the less likely the technology will be used, but it is a thought.

Back to the crazy Troposphere Sink idea. Computer models use a lot of simplifications to try to predict global climate. The majority of the uncertainty is in the water feedback and the ocean response. I tend to be in the balancing effect of water vapor trough cloud formation and precipitation increase camp. I also tend to think the oceans are more of a long term thermal reservoir capable of dealing with a lot more heat than the models give them credit. Jeff Id made a post at Watts Up With That showing that the oceans could give up about 0.1 percent of their heat content and warm the atmosphere by 4 Degrees or so. Conversely, a small increase in ocean heat content would offset a huge amount of potential warming. The Troposphere Sink is much smaller in comparison to the oceans. So if the Troposphere Sink can moderate warming, it has to be able to improve the release of heat more than just hold the heat.

I have been reading up on the models used by the models for the radiation balance in the region of the Troposphere and lower Stratosphere. While I am no where near up to speed on the radiation models, it appears that fairly simple two dimensional are still the norm. The three dimensional model modules are mainly reserved for winds, currents and such. Constant humidity with temperature rise is also estimated, which is reasonable. Rainfall based on the increased temperature/constant humidity are somewhat realistic, but there are issues, mainly since reconstructing precipitation in the past is difficult. It is a huge project that already has millions of man and computer hours spent to get the models as close as they are. While I may be crazy, I am not stupid, so I am not going to try and reinvent the wheel. I will spend a little time looking into the tropopause region models to see if there is something that may explain why that region may be an effective sink.

Two things come to my mind which I want to look into the sink. The first is if the radiation window in the tropopause region might be larger than thought. To use a radio analogy, the top of the troposphere may behave somewhat like a ground plane for an antennae. While IR won't bounce off the water vapor at the TOT (Top of Troposphere) it may give the IR in that region more options to escape to space. The "Back Heating" is just as crappy a term as "Back Radiation", but it does poorly describe the way that as the humidity in that region rises, more heat in a thin layer may be possible. The other is water vapor transport to the Stratosphere just above this warmer, moister region. Susan Solomon and friends published a paper on how stratospheric water vapor changes impact climate. Small changes in the already small concentration of water vapor in the TOT region can have big impacts on climate. Noticing that the TOT temperatures can vary by 30 degrees C, makes me think my silly idea may have something to it. Then if it is totally whacked out, I am in good company.

If you want to read more about Global Warming and Global Circulation Models, this site has a good history of the research, Global Warming Time Line. You can even sign up to be a part of the modeling effort by donating some of your personal computer time. If I can fiddle with the TOT radiation model a little I may just do that.

Back to the Future - Hydrogen Power Motor Coach

Note: This is just a scratch pad I am using to clean up the RV of the Future post. If it cleans up good I am planning to publish it.

I live in a motor home. Once you discover that 75.3% of the stuff stored in your garage is never going to be used, more than half the clothes in your closet don't fit and that the few useful things you have stored only mean work you are not really serious about under taking, it is easy to down size to a motor home. Everyone's idea of the perfect motor home is not the same.

Determining the perfect motor home boils down to a cost versus inconvenience ratio. The cheaper you are the more inconvenience you can accept. I am a middle of the road personality with a cheaper than normal reality. So I am going to describe the logic I use determining my concept of the RV of the Future.

A little background first. Motor homes are generally big. A 30 to 36 foot long RV is not uncommon, like a fairly large bus. Unlike a bus, RV generally do not get driven very often or very far over their life. So the power plant for motoring along the road, a large diesel or gas engine is pretty much a waste. Since the drive motor is very large, a smaller generator motor is used since it is more efficient for producing electrical power than the monstrous main engine. Hot water can be furnished by either the main motor or the generator motor, but generally a separate propane hot water heater is used because keeping the fuel powered motors running is expensive both in fuel and in maintenance costs. Combining all these functions would seem to be efficient, but how? Fuel cells are how!

A motor home needs a motor. For this hydrogen version we are going with the Azure Dynamics AC90 Electric traction drive and controller. I toyed with in-wheel electric motors, but they were limited on torque. The AC90 has enough torque with proper gearing to handle the estimated 12,000 pounds (approximately 6,000 Kg) that the complete vehicle will weigh. Thanks to Azure Dynamics design for hybrid trucks and buses, this saves me a lot of time calculating all the performance variables. This big beast is not cheap, suggested retail for the motor and required controller is right at $11,000 USD.

While they are not a perfect match, a pair of Ballard Power FC Velocity 9SSL fuel cells which can provided 40kW of power for a total cost of $20,000 USD, are our power plant both for the motor and normal electrical needs in the motor home.

I don't want to get into too much detail so I am just going to mention that power inverters for house electric, cooling systems for the fuels cells, basic energy management system and assorted electrical stuff will be needed, adding another $9,000 USD to the combined power plant cost using reasonable quality components. Remember, that is just an estimate, you can throw as much money at all these things that you want. That will give us roughly $1000 USD per kW initial cost. In the normal world that is about $20,000 USD more than the standard gas power plant of typical motor home. Diesel pusher motor homes are about mid-range between the gas and hydrogen options.

The fuel cell option does a lot of neat things though. It not only replaces the main engine, it also replaces the generator, hot water heater and has enough electrical power to use less expensive and more reliable appliances.

Unlike most hydrogen or electric vehicles, the motor home fuel cell option reduces the overall weight of the vehicle by about 500 pounds. That is mainly because it replaces the generator and the main motor.

All motor homes have a battery bank for house use and starting. With the fuel cell version we are just going to upgrade the batteries. While lithium ion batteries are great option, specialized lead acid batteries have a long life, 10 years, which is nice for this application. These will take back all of that weight savings since they have a lower power density than the Lithium Ion batteries. The longer warranty, lower cost and ease of maintenance make the good old lead acid batteries my choice. At over $3000 for a set of three, that sounds like a lot, but $300 a year replacing used batteries is not uncommon for RV users.

If you just want to be green and impress your friends, this basic FCRV (Fuel Cell Recreational Vehicle) would do the job. Personally, I am cheap. So a home hydrogen refilling station using solar panels to make my own fuel is a must.

The home hydrogen refilling station and solar panels to provide juice needed to give me the best bang for the buck. There are a variety of manufacturers providing 3 to 5 Kg per day home hydrogen refilling systems for about $2300 US. A solar Photovoltaic array on the roof of the RV costs about $1 a watt using Nanosolar's panels. A 25 foot by 8 foot (approximately 18 meters squared)array would produce approximately 2 kw per hour during daylight hours (10kw per day average). With current fuel prices, these systems pay for themselves in a year or two depending our your RV use habits. The battery bank will hold about 16kW worth of electric, so the solar panels will top off the batteries during the day plus offset daytime electric use. At night the batteries take over to provide uninterrupted power. If there is really heavy electrical demand, the fuel cells will kick in as needed.

It makes no sense to use hydrogen to make hydrogen, that is a losing situation. So the inverter running the home refilling station will have to be smart enough not to drain the batteries or run when the fuel cells are charging the batteries. That is a pretty simple job for the energy management system. Storage of hydrogen is not much of a problem for motor homes. The center line of the chassis offers plenty of space to install 3000 psi tank systems. While higher pressure systems are available, just matching the pressure range of the home hydrogen refilling system is all that is needed. High Density PolyEthylene (HDPE) lined steel or aluminum tanks are a less expensive option to the carbon fiber tanks being developed. Hydrogen is an energetic little atom, so the HDPE lining is recommended to contain those little rascals and prevent long term damage to the tanks.

About 30 kilograms of hydrogen storage would give the FCRV a similar range as a standard 30 gallon fuel tank. The hydrogen tanks require over 4 times the volume for the same energy, but that is no big deal for a 30 to 36 foot RV. The density of hydrogen at 3000 psi is close to 1 pound per cubic foot. Converting to metric that is about 16 Kg per cubic meter. 2 cubic meters which is about 70 cubic feet, may be a lot of space for a car or truck, but in the FCRV that is only 6 ft by 12 of center line chassis space. Not that hard for a RV being built chassis up. There is still plenty of room for fresh, black and gray water tanks plus reasonable basement storage.

To maximize the hydrogen production, electrical use needs to be decreased with higher efficiency. RV's are not very well insulated. Adding insulating window coverings, reducing window area and adding a little insulation to the shell of the RV will do wonders. The typical RV has two main air conditioning systems normally rated for 13,000 BTU. Only one at a time is used most often. The attention to insulation will reduce the required A/C capacity. So two smaller 8,000 BTU units capable of running at the same time if needed, will reduce the overall energy required for space conditioning. AT 8,000 BTU, approximately 900 watts with a duty cycle of 50%, air conditioning would require 4.5 KW per day in cooling season. A refrigerator/freezer with ice maker is approximately 1KW per day with lighting and electronics averaging less than 1 KW per day. Properly designed, during the worst energy usage season, an extra 3.5 Kw per day would available for hydrogen electrolysis and battery trickle charging. Luckily, peak cooling demand time is also peak solar time. So if that second A/C is needed, it won't over tax the energy system.

Getting back to the drive system, the power provided by the FCV 9SSL cells is not enough for acceleration and climbing grades. The batteries will have to kick in to provide performance when needed. The capacity of the batteries can provide about 20 minutes of boost power. That is enough for most situations. It will require a little more attention to driving economy, limited to actually doing the speed limit most of the time. The estimated top speed of the loaded FCRV is about 80 miles per hour. Normal acceleration would be a little over 5 meters per second giving you a 0 - 60 mph time in the high teens to low twenties of seconds. That is respectable for a big motor home.

The life span of the fuel cells is a big question for most people. The Ballard Power product has a life listed at 8,000 to 12,000 hours. That is based on the efficiency of the heart of the fuel cell, the Proton Exchange Membrane (PEM). This is a maintenance issue. Changing the PEM every 10,000 hrs should cost in the $1,500 to $2,000 range every five years. That of course depends on how much driving time the FCRV gets on the average. Most RV's never get driven more than 20,000 miles. So the PEM maintenance may only be needed every ten years. Do note that the FCV 9SSL is made for use in fork lifts. Before Ballard Power signs off on this design, they would have to re-evaluate what warranty they may offer if they approve the alternate use. They do make a bus module with a cost range of $300,000 to $600,000 USD. That is way beyond the price range of all but the wealthiest RV enthusiasts. They are working on automotive fuel cells that would be more compatible price wise.

Based on my own RV, monthly electric and propane cost are around $150 USD. So over five years, that is $9,000 USD. If you factor in the lower lot rental between a full hookup and dry campsite, about $200 a month average, that is another $12,000 over five years. So if you live year round in your motor home, the fuel cell system comes close to paying for itself in five years. Back country campers can really use the self contained benefits of the FCRV. Also, responders to natural disasters could really use the FCRV for their jobs where power and lodging are not readily available.

It may be a little early to jump into a FCRV, but the overall cost is getting more inline if you consider all the advantages. Ballard Power may also consider diversifying the use of their FCV9SSL line. Not only can it be a valid option for automotive, it would be a great option for replacing the expensive battery packs in the new electric vehicles.

This PDF provided by the department of energy details the validation of hydrogen fuel cell vehicles. While future cost versus performance of the fuel cells will decrease, Ballard's material handling fuel cells used by Plug Power may have a jump on the competition. Time will tell.

Fuel Cells, Electric Drives and Other Fun Stuff

When I am playing with my fantasy designs I contact a few manufacturers to get more information on products that I am going to use. Ballard Power is one that I have been following a long time. The FC Velocity 9SSL is the main fuel cell they make that I use for my pseudo designs because it has good power density, long rated life and reasonable pricing. The cost of the FCV 9SSL is $10,000 for 19.3kW which is $500 per kW, but in the articles I typically use the total system cost per kW which may be confusing. For example:

For electric motor drives I have switched to Azure Dynamics products. The big AC90 and controller they make costs $10,900 plus shipping. With estimates for the remaining drive train and fuel storage that brings the system cost with fuel cells to about $1000 per usable kW. Where possible I will list the individual prices, but unfortunately some have to be approximations.

Nanosolar solar cells are estimated at $1.00 US per Watt. That is just the panels so shipping, installation and associated equipment, inverters etc. need to be factored in for your application.

Another thing that I have mentioned is servicing fuel cells. The FCV 9SSL has a life listed of 10,000 hours. That is basically the life of the PEM before efficiency is degraded to 70%-80%. The PEM can be replaced to rebuild the FCV 9SSL back to original performance for a cost that is not clear. The PEM material cost is approximately $500 per square meter. So I estimate approximately $1500 US for a rebuild which I feel is reasonable. Of course, that can vary.

If you are planning to use a Ballard FCV9SSL for power generation for example, the total system cost would be less than for an automotive application. The use would also impact the estimated life and thus the warranty of the product, since it is not rated for that application. That also applies to my automotive uses until in production.

Ballard makes fuel cells for remote power applications which are designed that function and have specific estimates for that purpose.

Anyway, I find that hydrogen fuel cells have made great progress in the past 5 years and honestly expect they will become a part of every day life within the next decade.

My Fuel Cell Tahoe

I was going to do a sports car kinda thing, but I am a SUV kinda guy that needs space to haul my stuff and tow a boat. So if I had the cash, this would be my mean green machine.

Doing the RV of the future I stumbled across a few interesting things. First that in-wheel motors have potential, but if I want my dream Tahoe now, it is better to go with a big honking motor and mechanical gearing. Azure Dynamics makes the big AC90 electric motor that has some serious butt. They also make a mid-range, AC55 Force Drive (TM) which is more of a pick'em up size motor. I will stick to Ballard Power's FC Velocity 9SSL fuel cell, rated at 20 kW. I am going with two, so one can be mounted on each side of the AC55 under the hood. I am a rear wheel drive fan and it is neat to pop the hood to show stuff off and symmetry is pleasing on the eye.

I will use the standard automatic transmission from the 2011 Tahoe to make things simple. I may have to play with the rear end a little, but the RPM range of the AC55 is a pretty good match other than the best performance range is higher than the typical internal combustion engine.

The AC55 provides a pretty flat torque of 280 NM until it hits 2100 RPM then it slope off. Efficiency is pretty flat as well, but there is a hump in the power requirement that means we will have to play with batteries for boosting power during acceleration. I will stick with a pair of 8D lead acids for boost and fiddle with the gearing to reduce their use. The pair of 8D's will provide up to an hour of 6kW boost, so we need to be careful with energy management, but extra battery storage should not be a problem. Going with more expensive Lithium Ion batteries is an option worthy of consideration in the Tahoe's case though.

Hydrogen storage is not as much of a problem with the full size Tahoe frame. Where the normal gas tank would be, a triple set of High Density Polyethylene (HPDE) lined aluminum tanks rated for 3000 PSI will go. We can also stick a pair of longer HDPE lined tanks inside the running boards with a little lift kit to provide clearance. We should be able to get about 20 to 25 kilograms of hydrogen storage with this configuration. The 8D's should fit nicely under the hood below and slightly in board of the fuel cells with the AC55 controller mounted in front of the motor. Split cooling radiators, one for each fuel cell, will be mounted in the normal radiator location. The total weight will be close to the original big V-8 that is being replaced since the AC55 only weighs 106 Kilos. That is pretty simple! We don't even have to fiddle with the suspension other than a lift kit.

280 NM of torque is equal to 206 Ft-Lbs which is less than the maximum torque of the Chevy V-8. With the rear end change, the torque at the wheels will be closer for towing performance. For a towing package, we could even consider a high/low rear end which may be pretty trick. While gearing can over come a lot of issues, it is not much help on top end. 80 MPH for normal load and 70 for average towing is going to be about the limit. I can live with that since I will be getting about 25% better fuel mileage than the standard V-8. That may be more, but with about 54% overall efficiency and much less cost per gallon equivalent, it is not bad.

The cruising RPM of the AC55 needs to be limited to the 1500 to 2000 range to match the 25Kw continuous Kw and Torque of the AC55 drive motor. As I mentioned, this range is a good match for the standard transmission and rear end of the Tahoe. It also means the rather small battery storage should fine for normal use. The beefier AC90 with either larger fuel cells or more battery backup could be a heavy duty option. Since Ballard and Azure Dynamics are not on the same page right now, a better option should be available soon.

Cost wise, the FCV Tahoe will be a little higher than the higher estimated cost of $56,000 for a hybrid. Unlike a RV, a SUV gets plenty of mileage, so the home brewed fuel will be a big factor to consider as well as 10,000 hour PEM maintenance on the fuel cells. Ten thousand hours is about 40,000 miles depending on use of course. If we can get one free PEM service from the dealer along with $2500 for the solar home hydrogen refilling station, that would give us about 3 cents a mile low end fuel cost. Including an estimated $65,000 MSRP, the cost per mile, hoping no significant maintenance costs, would be $0.83 USD based on 80,000 mile life. A little on the high side, but not as bad as five years ago. If the PEM replacement cost is not too high, a used SUV buyer could get a great deal.

PEM maintenance is the biggest factor with fuel cells. While the 10,000 hour limit may be a little flexible, to keep efficiency up, it has to be done. It doesn't look that complicated and the cost of PEM material is way lower than a few years ago. That would be an interesting subject for another post.

In case you are wondering, I selected the Ballard Power FC Velocity 9SSL because it is in production for the materials handling market which reduces the cost per kW considerably. At $1000 per kW they are much more attractive than the larger 75kW bus style at roughly $4000 per kilowatt. Target price for an automotive size fuel cell is $30 a kW (net) which will require some serious production to match. Exactly what that cost per kW (net) translates to for the end user, I am not sure. By 2015 though the $1000 per kW should be closer to $500 which will be more inline with a standard gas power option. Also, the 10,000 life is based on material handling usage. For an automotive application it may be less.

Just playing with off the rack components, the cost and performance of FCV's is getting close. My calculations are pretty rough. With a focused design all sorts are things are possible. Still, I think the twin fuel cells may be something worth looking at because load balancing could really extend the life of the cells. It would also look pretty cool under the hood.

The RV of the Future

I live in a motor home. Once you discover that 75.3% of the stuff stored in your garage is never going to be used, more than half the clothes in your closet don't fit and that the few useful things you have stored only mean work you are not really serious about under taking, it is easy to down size to a motor home. Everyone's idea of the perfect motor home is not the same.

Determining the perfect motor home boils down to a cost versus inconvenience ratio. The cheaper you are the more inconvenience you can accept. I am a middle of the road personality with a cheaper than normal reality. So I am going to describe the logic I use determining my concept of the RV of the Future.

A little background first. Motor homes are generally big. A 30 to 36 foot long RV is not uncommon, like a fairly large bus. Unlike a bus, RV generally do not get driven very often or very far over their life. So the power plant for motoring along the road, a large diesel or gas engine is pretty much a waste. Since the drive motor is very large, a smaller generator motor is used since it is more efficient for producing electrical power than the monstrous main engine. Hot water can be furnished by either the main motor or the generator motor, but generally a separate propane hot water heater is used because keeping the fuel powered motors running is expensive both in fuel and in maintenance costs. Combining all these functions would seem to be efficient, but how? Fuel cells are how!

That big motor in the average motor home may produce 200 horsepower peak of their rated 250 or more. Rarely is half of that horsepower ever used. So let's see what a fuel cell can do for us.

About 50 Kw (68 HP) is all that is required for normal driving. Thanks to drive train losses with converting the gas power horse power to RV motion, 100 KW will push the RV along about as well as 200 horsepower the main motor can produce. The fuel cells produce electrical and heat energy so they should be sized for needs of the campground conditions. Ballard Power manufacturers fuel cells and was nice enough to send me some information on their products. One of their most popular products is used in materials handling, fork lifts. The FC Velocity 9SSL I would use provides 20KW with an average life of 10,000 hours for $10,000 dollars. I could special order a FC Velocity designed for 25 KW, but let me see if I can make the off the rack fuel cell work.

Two 20Kw fuels cells would yield 40Kw or 54 Horsepower. That is enough for basic boring driving, but not quite enough for passing or quick acceleration. I am use to fellow travelers flipping me the bird, but some people may not like that. So I should have a little boost potential to avoid single finger salutes. Batteries? They can provide that short term boost and be useful for other things. So I will keep the three battery bank that my RV already has for back up power and add a couple. That solves my flat lander situation but not the mountain climbing mode, or does it?

Regenerative braking, using braking power to charge batteries is pretty common. A great deal of the battery boost used would be recovered in slowing the big beast down. So it is possible that 40 KW from fuels cells and some amount from batteries will cover all the traveling needs. That doesn't sound like much for a big motor home, actually, now it is a "Motor Coach". This RV of the future needs a classier name.

Comparing a fuel cell with electric drive to a internal combustion engine (ICE) is a little complicated. ICE has a narrow power band and efficiency range. A diesel that may be 45% efficiency at some point in its operating range will only average about 37% in normal operation. Electric motors average over 90% efficiency. Electric motors also have a flatter torque curve. In wheel or hub DC electric motors would be the perfect option for the Future RV. Ford, sticking with the North American theme, produced a prototype F-150 with Hi-Pa in wheel motors. The Hi-Pa Drive HPD-30 is rated for 350 NM (258 Ft-Lb) torque, 40 KW, with maximum speed of 2000 RPM. One HPD-30 paired with a FCV 9SSL (20KW) and battery bank boost of up to 20KW would be the main drive for the RV. This total of 40KW (54 HP) with 40 KW (54 HP) battery boost for a total of 108 HP (516 Ft-Lb torque) doesn't sound like much. 108 HP with 516 Ft-Lb torque though is a good match for the nominal torque provided by the Duramax Diesel 6.6L Turbo while requiring half the horsepower. The class C or bus style RV's have the aerodynamics of a brick. A modified Class A design will cut the air better improving driving efficiency. Battery load would limit range requiring adaption of driving habits (limit cruising speed to 55 to 60 mph)so this should be considered a minimum configuration. The reason that this can even be considered a minimum is that the weight of an average RV is deceptive. While the chassis of a 30 to 34 foot RV may be rated for 26,000 pounds gross weight actual weight is about 1/2 that and most of that is the engine, drive train and chassis.

Thinking in terms of torque makes understanding the in wheel Hi-Pa drive easier for gear heads. Torque is what moves the RV. Horsepower/engine speed has to be converted by gear ratios into torque at the wheels to move the RV. Once the RV is moving, gearing can reduce the torque at the drive wheels to produce high wheel RPM and vehicle speed. So if the electric motor system can provide the required torque where it is needed, forget the horsepower. Once the vehicle is to the desired speed, the motors only have to counter friction and wind resistance to maintain speed.

Accelerating the heavy RV requires a little electrical trickery. Electric motors at low voltage draw a lot more amperage than at nominal operating voltage. We want the torque not wasted heat, so pulsing DC, at rated or higher voltage for short periods or pulses (pulse width modulation), is provided instead of just varying the voltage. This pulse width modulation is in essence our gearing. By watching the gross vehicle weight and aerodynamics, the 108 peak "horsepower" is enough for normal operation. Higher performance for towing or just impressing your friends will cost more money as in more fuel cells and four wheel drive or a hybrid engine for peak performance.

Gross vehicle weight using the FCV 9SSL is interesting. The pair of fuel cells weigh 34 Kg (74 Lbs) dry weight versus Duramax engine and transmission weight of approximately 1000 Lbs. The Hi-Pa drives weight, while not negligible, is rotating which has less impact on gross vehicle weight. Subtract the approximately 600 pounds for a standard generator and the remainder of the drive train and you have a net weight savings of about 1800 pounds. Since hydrogen has a lower power to weight ratio than gas or diesel, we save on fuel weight as well. The battery weight for the FCRV will be slightly more than the normal RV battery weight by about 100 pounds (5-8d batteries versus 4). However, selecting a heavier more powerful battery set is not a bad idea.

While lithium ion battery technology gets all the press, lead acid specialty batteries have some advantages. The Surrette 4-KS-25PS battery is a solid four volt deep cycle with 1350 amp hours (versus 1250 amp hours for a five 8D battery bank). A set of three to provide 12 volts weighs 945 pounds, but has a ten year warranty. Note: both would allow for approximately 20 minutes of peak power. That would add back about 400 pounds of weight savings but with more stored power and much better longevity. While other voltage options would be better, current DC accessories rated for 12 volts provide an overall cost reduction for the RV.

Hydrogen production and storage is a big consideration. Quantum manufactures composite hydrogen storage tanks. Cost and longevity wise they are not up to snuff today, but may be on the right track for the future. A less expensive alternative is HDPE lined aluminum tanks. HDPE is high density polyethylene or plastic used to line hydrogen storage tanks to reduce leakage. The aluminum, HDPE tanks limit the maximum storage pressure to 3000 PSI. With a RV chassis, there is plenty of center line space for 50 Kg for hydrogen storage even at the lower pressure.

Producing your own hydrogen is not only a cost saver, it is now a requirement since the hydrogen highway is no where near completed. A reverse cycle fuel cell electrolyzer would be trick, but right now we have to settle for a separate electrolyzer for home refueling. There are a variety of manufacturers providing 3 to 5 Kg per day systems for about $2300 US. A solar Photovoltaic array on the roof of the RV costs about $1 a watt using Nanosolar's panels. A 25 foot by 8 foot (approximately 18 meters squared)array would produce approximately 2 kw per hour during daylight hours (10kw per day average). With current fuel prices, these systems pay for themselves in a year or two depending our your RV use habits.

For this system to be self sustaining, energy saving appliances would be needed. Air conditioning is the main power hog. Insulation of RV's is mediocre at best. Insulated window coverings and 1/2" closed cell polyisocyanurate foam sheathing would more than double the R value of the typical RV. This would reduce the typical cooling capacity required from 13,000 BTU to approximately 8,000 BTU. AT 8,000 BTU, approximately 900 watts with a duty cycle of 50%, air conditioning would require 4.5 KW per day in cooling season. A refrigerator/freezer with ice maker is approximately 1KW per day with lighting and electronics averaging less than 1 KW per day. Properly designed, during the worst energy usage season, an extra 3.5 Kw per day would available for hydrogen electrolysis and battery trickle charging. A second AC could be added for peak cooling demand which would eat into our hydrogen budget a bit. Fortunately, that worst energy usage season would also be the highest solar energy production season. We can fine tune these estimates, but they seem quite reasonable at this time.

So how does all this compare cost wise? Two FCV 9SSl totaling $20,000 is the major cost. It is hard to find a real price for a Duramax with transmission. My estimate for brand new out of the crate would be $15,000. Differences between gas and diesel for new RV's range between $15K and $30K. Some of that is due to chassis type,but as and estimate, FC power will cost about $5,000 more diesel and about $10,000 than gas. For another $10,000 you could add an extra fuel cell to impress your friends. I could not get a good price estimate for the HPD-30 in wheel motors. An addition $7,500 should cover two HPD-30's and drive/regenerative braking modules. Fuel cost for most RV's is nearly impossible to figure. The average miles put on a RV is only 20,000 miles with about 12 miles per gallon average. At $3.00 per gallon that is only $5,000 dollars. On the other hand electrical and propane cost is about $120 per month average. Over five years that is another $7,200. For a wilderness camper, the saving would be much more because generator electricity is more expensive.

Maintenance wise, the Ballard fuel cells are rated for 10,000 hours. That is virtually maintenance free. Then the PEM, Proton Exchange Membrane, should be replaced if performance is degraded. If the Fuel cells are installed to allow easy access, replacement could be a simple maintenance program every 4 to 5 years. The electrolysis refuel system would have a similar PEM schedule and filters/water treatment system maintenance schedules.

Depending on your expected use, the FCRV can be a good option now. For example, FEMA responders often take their RV for housing and office space in areas with little chance of reliable on site electric service. The totally self contained FCRV would be well worth the added cost.

I need to better model the average energy per mile driving to allow for regenerative braking and wind loading, but my estimates should not be far from reality, provided the true gross weight of the RV is 50% of the gross chassis rated weight. Ballard Power does make a 75KW FC 900 series for automotive that is not available for this article. While a bus style 150kw FC would seem to be the proper selection for the RV, real world conditions should not require that much continuous power. I will proof and modify this in the future, for now though it may be of interest.

So how slow will this bus be? Acceleration A = T(orque)/M(ass)x R (tire radius)

T = 700 M=3000 and R= 1 for simplicity So acceleration is equal to 0.23 meters per sec. That is slow! We need to get to 100 KPH(62 MPH) in a reasonable time, say 20 seconds, which is an acceleration of 5 meters per second. Back calculation then requires a torque at the large wheels of 5 MPS times 3000 Kg times 1 meter = 15,000 NM So changing the radius of the tire to something more realistic, 0.25 meters, might work but we have to look at the top speed which is limited by the 2000 RPM of the in wheel motor. If we feel we can get away with 120 KPH which is a top speed of 75 MPH, we get a wheel circumference of 1 meter. That gives a radius of 0.16 meters or a tire that is 0.32 meters tall or 12.5". That is a pretty unrealistic tire. So we have to compromise to something realistic, but smaller than we would normally wish to reduce the torque. Let's pick a 20" tire. That has a radius of 10" or 0.254 meters.

Torque required with this wheel radius is 3810 NM. That would mean the Hi-Pa HPD30 is not a good choice. We need 1905 NM per wheel for two wheel or 950 NM per wheel for 4 wheel drive. Unfortunately, it is hard to get in wheel motor information, and most designs are for light passenger vehicles. The HPD series has the higher torque HPD35 and HPD40, but according to the literature, the KW per torque is less attractive than the HPD30. Solution, tandem rear wheels and front wheel drive. That would give us 6 time 350 or 2100 NM total torque. Not as much as we want, but what will it do?

Still shooting for the 5 MPS acceleration we have 2100/(5*.254) equals 1650 kilograms or 3630 pounds of vehicle. That is a little small for a "motorcoach". We only need about 60 seconds of extra acceleration, so what low weight options are there?

Azure Dynamic makes an AC motor for medium weight trucks. This option brings us back to typical mechanical gearing. Also the AC90 manufacturer states that regenerative braking options are there. Weight and input power wise it is an interesting option. The AC90 with controller weigh in at 216.5 Kg (476 pounds) with 97 Kw peak shaft power and 50 Kw continuous power. While the torque is about the same as a pair of HPD30 in wheel motors, we can more easily use mechanical gearing to get the wheel torque required for acceleration. Shame really, because the in wheel design could do the same thing. I have an email out to the HPD30 manufacturer to see if they have addressed that issue.

This change brings me right back to my estimated 50Kw which we have only 40Kw to work with plus battery boost power of up to 40Kw for a limited time. The power curve for the AC90 gives us an operating point at ~4200 rpm where we meet the 40 Kw available from the pair of FC Velocity (SSL). It is a compromise that will work, maintain our energy budget, provide reasonable acceleration and thanks to mechanical gearing, maintain a reasonable cruising speed. If I were King, I would get Azure Dynamics to rework the AC90 for 40Kw continuous power input with 80Kw peak. On the other hand, I might get PML, the manufacturer of the HPD30 to modify their design. One might think that I would get Ballard Power to custom build a 25Kw version of their FC Velocity 9SSL, but with mechanical gearing being required anyway, there is no need, 40Kw can push the "motorcoach" along nicely once we accelerate the load.

So my dream RV of the Future may be built with off the rack components right now. Using a pair of FC Velocity 9SSL or three if I wanted more power, only costs $10,000 per fuel cell. A 150Kw fuel cell for a bus costs upward of $600,000 US. So hydrogen fuel cell vehicles are not as much of a dream as you might think. While I may come back to this post to fine tune the basic design, I will tackle either a zero emission fishing boat or refine my green Tahoe next.

The Political Aspect of a Hydrogen Economy

Before the exciting diversion of Fukushima, which I pronounce oddly, I was building on misunderstandings of other transportation fuel options. Natural gas makes perfectly good sense from a energy security perspective, but squat from a CO2 emission perspective.

Politically, the global warming issue is losing ground mainly because proponents suffer from the same lack of trust they toss around about individual governments. They seem to believe that one global government is a better option than a bunch of individual governments doing their own thing. Conspiracy theories are so 20th century. The realism is that a majority government by third world leaders is no better than a minority government lead by first world capitalists. Bribery, corruption and stupidity are not reduced by increasing the number of players. Gridlock is, so that may be the only advantage of one world government.

Infrastructure cost is for some odd reason, one of the political stumbling blocks for hydrogen. An initial basic hydrogen infrastructure is only about 2 billion. That is a fraction of the subsidies for wind and nuclear power which no one complains about too loudly. That basic infrastructure is enough to start making Fuel Cell Vehicles (FCV) economically viable. If you can't fill up on the road why buy one? The basic infrastructure would initially limit FCV use to the more densely populated ares, but everything has to start somewhere.

America has an advantage in leading the alternate transportation energy front. For whatever reason, the rest of the world covets our neat toys. Other countries bitch about our gas guzzling SUVs, but foreign sales have remained strong. As I have said before, FCV's will be big gas guzzling looking vehicles that happen to be efficient and "green". Damn the bad luck. Shouldn't we all drive Mini Coopers packed to the gills with kids to look like we care about the environment? Maybe doing something instead of appearing to, makes sense?

Anyway, is a road system full of "green" Hummers really that absurd?

More on Hydrogen Fuel Cell Vehicles

I drive a SVU. While I don't need to all that often, I have to tow a boat weighing up to 7 tons every now and again. That is hard to do with a bicycle or Mini Cooper. There are plenty of people that drive big SUV's because they can, not because they need to. Many parents want their kids driving bigger vehicles because they are safer than smaller vehicles. Whether for need, status or piece of mind, big vehicles make up a large portion on the vehicles on American roads. Hydrogen fuel cells are tailor made for these vehicles.

Hydrogen is the lightest element in the universe. That makes it hard to contain. There has been a lot of research to improve our ability to contain hydrogen well enough to make it a viable fuel. Pressurized hydrogen appears to be the best way to contain this fuel. Liquid hydrogen works great, but it has to be kept at a very low temperature which means refrigeration energy or super insulated containers. Under pressure, hydrogen is a lot less expensive to store.

One kilogram of hydrogen is equivalent to one gallon of gas, energy wise. The volume of one kilogram of liquid hydrogen to equal one gallon of gas is 4 time greater than gasoline. The U.S. Department of Energy has funded research and development of high pressure hydrogen storage tanks for vehicles. The carbon fiber tanks lined with high density polyethylene, can store 15 gasoline gallon equivalents in roughly 60 gallons of space at 10,000 PSI (700 bar). At 10,000 psi the energy density is close to that of liquid hydrogen. The weight of the filled hydrogen tank is less than the weight of the filled gasoline tank. At 3000 psi (200 bar)the volume of equivalent energy would be 3.5 times greater. It is the required volume that is the issue.

The reason I used 10,000 psi and 3000 psi has to do with the energy efficiency in delivering the hydrogen. High pressure hydrogen electrolysis produces hydrogen at roughly 3000 psi. No extra work has to be done to compress hydrogen if 3000 psi provides reasonable vehicle range for its tank size. While US natural gas pipelines are currently rated for only 1200 psi, compressing from 1200 psi to 3000 psi is a lot cheaper than to 10,000 psi. Looking into my crystal ball, I think I see nominal 3000 psi hydrogen pipelines in our future.

A compact car would be difficult to put a large hydrogen tank into. A SUV would handle a bigger tank(s) with greater ease. Even a big SUV has limits. 100 gallons of fuel space, about 14 cubic feet, or four - one foot diameter tanks eight feet long, would be a realistic maximum. That tank configuration would be equal to just over seven gallons of gas. Since the Fuel cell is more efficient (40 MPG) than an internal combustion engine (20 MPG), the range of the vehicle with a low pressure hydrogen fill would be about 285 miles. Should you want to make a long road trip you could pay the extra cost for a 10,000 psi full up and get a range 3.5 times greater, or 1000 miles. That is just an example. With only two tanks you would have about a 140 mile low pressure range and a 500 mile high pressure range. The actual low pressure range, since it would generally be for in city driving, would be higher with regenerative breaking.

I approximated a little, but these numbers are in the ballpark. For comparison the Chevy Equinox FCV gets 43 gasoline equivalent miles per gallon and a 200 mile range with about 4.5 kilogram tank. There are other considerations. Current fuel cells have a 50,000 mile life before overhaul. The overhaul is basically replacing the PEM, which is the Proton Exchange Membrane. So instead of ten $50, oil changes you would have one $1000 PEM change every 50,000 miles. I am guessing of course on the costs. PEM using a platinum catalyst are more expensive than non-precious metal catalyst membranes. At around $550 per square meter, the platinum PEM material is much cheaper than many think. So those numbers may not be too far off.

The biggest problem is the hydrogen infrastructure. Compressed natural gas proponents brag about their existing infrastructure. It is there, but you have to look to find it. The four tank system I am talking about may seem like over kill, but until the hydrogen infrastructure catches up, it is good choice for rural users more inclined to have home hydrogen refueling stations. More on that later, but there is a huge difference between 3000 psi and 10,000 psi home fueling systems.

A few links:

This first one shows a insulated liquid hydrogen prototype with a 650 mile range. Remember the 10,000 psi tanks are about the same size since they do not have the thick insulation. With the liquid hydrogen, the fuel boils off in about 6 days, not a good thing.

This one is a low volume home hydrogen fueling station designed in the UK. It is an older design that I list mainly to show the relative cost.

This is a Honda solar home refueling system that product 1/2 gasoline equivalent gallons (0.5 kilograms) per day. Standard home electric versions can produce more in even less space.

This is a US government estimate for a Home Hydrogen Refueling (HHR)appliance. The estimated cost per kilogram is around $4 per kilogram which with the added fuel efficiency of the fuel cell is similar to $2.00 a gallon gasoline.

Note: All estimates based on nominal 60% fuel cell efficiency.

Our Energy Future and Counter Productive Thinking

For every positive view of an energy option there is at least one negative view of that same option. Depending on the last report read, the opinion of the general public sways. Is our energy future about politics?

Pretty much. Warm and fuzzy ideas like corn to ethanol and compact fluorescent light bulbs are embraced while better efforts are ignored by most but the faithful. Hydrogen technologies take a political beating while battery technology makes the headlines. So what is a hydrogen fuel cell fan to do? Just keep the faith and continue the research.

While it is far from a perfect analogy, look at your cell phone. Lithium Ion batteries are the cat's ass of battery technology. When brand new your phone holds a charge that amazes. Within a year that phone is old tech to be discarded in favor of a new high tech phone to wow your friends. That is about the time that that amazing lithium Ion battery starts lasting about half as long as it did when you first got your new old phone. If you happen to fall in love with your old phone because it doesn't butt call your friends, or you haven't bought a SIM reader to back up your stock of phone numbers, you have to start looking for a replacement or spare battery to keep it operating the way it once did.

The cost of a new battery for your cell phone is a minor PITA compared replacing the batteries in your one to two year old electric vehicle (EV). So we should write off electric vehicles because the battery technology sucks? I don't think so, you plan for the obvious.

That is what make Hydrogen so attractive, it has all the options to go with the energy consumption flow. Ballard Power has a niche industry they use to test fuel cells at at profit. Industrial material moving or fork lifts powered by hydrogen fuel cells. Ballard make a fuel cell module that replaces the standard lead acid batteries of electric fork lifts. So the EV affectionado has the fuel cell option to keep his/her pet EV running. EV's are short range vehicles for the most part. Converting an EV to low pressure hydrogen fuel is a near term reality. All the components are available and home generation of lower pressure hydrogen dropping in price. Demand is the key in all matters energy.

Long range alternative fuel technology vehicles require an infrastructure that meets their needs. Compressed Natural Gas (CNG) fans point out that there is already a CGN infrastructure. They are right, but you really have to look around to find it on the interstate. In areas with natural gas piped to homes for cooking and heating, for a fee, CNG owners can install a compressor to refuel their vehicles. Sweet! There is the compact fluorescent equivalent idea for personal transportation. Drop a couple of grand to convert your Internal Combustion Engine to CNG, throw another couple grand at a home compressor and off you go. Oh, but that demand thing pops up again. The existing natural gas pipelines are fine for current demand, normally, but additional demand would require more money thrown at upgrading the infrastructure. So blow off CNG? I don't think so. CNG vehicle run fine on hydrogen or hydrogen enriched natural gas. CNG fuel cells are also an option for the fuel cell gang that would prefer a hydrogen infrastructure but can make do with CNG.

Current hydrogen production is based on converting fossil fuels to hydrogen. So, can the hydrogen because it currently is not as "clean" as you fill in the blank. I don't think so because hydrogen has options, electrolysis and thermoloysis of water to hydrogen.

It is all about the options. Hydrogen is not an alternate energy, it is an option to use alternate energy with existing and future energy conversion technologies. Hydrogen is in our energy future.

A Matter of Semantics – Clean Coal

Clean coal technology is now perceived as a coal combustion cycle that includes carbon capture and sequestering. Clean coal technology is actually any combustion technology that reduces harmful emissions and/or significantly improves combustion efficiency.

A one percent increase in combustion efficiency produces a two percent reduction in carbon dioxide emissions. So if you double the efficiency of a coal fired power plant you halve the carbon dioxide emissions per unit power. That is a cleaner coal technology that does not involve carbon capture and sequestering. It is an imperfect solution as there are still carbon dioxide emissions.

Co-generation or combined cycle heat and power, is a method of increasing the thermal efficiency of power plants fueled by any form of fuel. Co-generation is the use of waste heat from the combustion process, which is over 60 percent of the energy conversion, to provide useful work. Less waste equals greater efficiency.

Waste heat use is common in industrial applications where both heat energy and electrical energy are needed in the processes. In public utility applications, waste heat is most often used as a means of providing steam or hot water for building heating. The overall efficiency of co-generation in public applications is limited by the means of delivering the heat energy to the consumer and the average need of the consumer for the heat energy or demand.

Demand varies with season which places limits on many co-generation designs. Electrical demand can be steady or inverse to heating demand and vice versa. Maximum efficiency in co-generation can only be obtained where the demands remain relatively equal. In new designs, co-generation can take many forms. Gas turbine power plants that use waste heat for low pressure steam turbines for example. This allows for balanced loading. Utilizing existing power plants with useful life requires more creative co-generation options.

Pairing public utility generation of either form of energy with industrial use that can vary as needed to maintain high efficiency, is an option for many co-generation projects. Since these pairings do not always exist, many clean coal applications include hydrogen production that can vary with the demands allowing excess heat or electrical energy to be stored in the form of fuel, hydrogen, that can be consumed as needed.

While hydrogen generation and storage has its own inefficiencies, it greatly increases the efficiency of the overall combustion cycle if the hydrogen can be used in a reasonable time frame. Hydrogen is not easily stored which precludes long term storage as an option. Hydrogen applications would be peak demand use or conversion to synthetic fuels which are more easily stored for longer time periods.
To optimize combustion efficiency, balanced demand for all forms of energy generated or stored would be needed.

Hydrogen enriched natural gas is a relatively simple means of balancing hydrogen demand. Hydrogen is added to natural gas that is piped for use by normal natural gas consumers. This application utilizes the existing natural gas infrastructure. Use of the enriched natural gas reduces the carbon dioxide produced by natural gas consumers depending on the percentage of hydrogen in the enrich product.

As hydrogen production increases, expansion of the gaseous fuel infrastructure would be needed to improve the overall efficiency of the energy co-generation system. Conversion of internal combustion engines from petroleum products to enriched natural gas will increase with the expansion of the gaseous infrastructure if the cost of gasoline equivalent gallons offset the cost of conversion. Fuel cell technology, which has a higher efficiency than internal combustion, would become more attractive as the gaseous infrastructure expands.

Since all forms of public energy generation have to adjust to varying consumer demand, generation forms that are not well suited to demand adjustment would benefit from using hydrogen production during off peak periods should the gaseous infrastructure be cost effectively accessed. Condition dependent energy sources, wind and solar primarily, would benefit despite the lower efficiency of hydrogen production via electrolysis. Nuclear and coal fired power plants would benefit by using sulphur-iodine thermolysis hydrogen production to improve co-generation efficiency in areas where more common co-generation applications do not exist. Wikipedia provides a long list of hydrogen production methods.

In a perfect world, non-fossil fuel based energy options would be abundant and easily matched to our current energy delivery infrastructure and energy lifestyle. Dealing with our past imperfect choices to move into a more environmentally friendly energy future will require compromises to avoid economic chaos. Utilizing existing infrastructure and generation sources in the transition to a sustainable, independent future will require increased thermal efficiency of existing components while alternate energy sources are improved and brought online. Clean coal, meaning high efficiency coal use, is unfortunately a part of the progression to an energy independent future.