Nuclear has not suffered a death knell. It's coming back very forcefully. This article reminds me of the theories of Professor Azar in Gotheburg.

The home DG market is fighting its own battles on numerous fronts, but I believe the major player to be the tough choice between storage and no storage. If one has the storage capacity onsite to accept more electricity on occasion without wasting it or selling it to the grid at the rediculous "avoided" cost, then it pays to purchase and install that extra capacity. Otherwise, that system is just another form of conservation from the grid's point of view. While large subsidies tend to minimalize this issue in some regions, it still remains a key factor.

Various forms of storage exist, each with their own pros and cons, but most today are inefficient and/or inappropriate for the home DG market. If home hydrogen production comes to the table, even at a reduced efficiency, the customer now has two benefits. Not only is it economic to have that additional capacity via the storage factor, but the crossover benefits to the transportation side double it's value. This opens the H2 auto market up to those who have excess home renewable energy capacity. The resident now has the option of using that stored energy in their car or their home as they so choose.

Since onsite H2 production isn't time dependent at all, all peak related energy costs, transmission expenses and central plant peaker generation can be reduced. All that needs to be done is coordinate any grid exchange with the time of day of the biggest benefit.

Projecting how long it takes this issue to come to light will answer your question of when the H2 economy will go into overdrive.

"Control of Tokamak Plasmas" by Alfredo Pironti and Michael Walker in IEEE Control Systems Magazine, Volume 25 Number 5, October 2005.

"Why Fusion?" by K.R. Schultz in IEEE Control Systems Magazine, Volume 26 Number 2, April 2006.

In particular, Dr. Schultz points out that using deuterium and lithium in first generation deuterium-tritium fusion reactors could provide all of humankind's energy needs for a world population of 10 billion people for about 700 years. He further asserts that a second generation fusion concept using the deuterium-deuterium fusion reaction would extend this supply to several millenia.

Pironti, Walker and Schultz, unlike Reynolds, seem to see the need for humankind to rely on a balance of energy sources that gradually change from the current mix of 86% fossil, 8% nuclear and 6% solar to more sustainable mixes as fossil fuels are consumed and new technologies such as fusion emerge.

Hydrogen as fuel, will never compete -never- with electricity by wire. This is for Dennis, you need 1.6 times the amonut of energy (as electricity) to produce a unit of energy as hydrogen. You are technically correct Distributed generation technologies powered by natural gas (with heat recovery technologies, 85% overall efficiencis) is the way to go with Building integrated solar PV in areas where the solar incidence is good enough.

Nulcear energy will have a bright future as far as technological developments of small nuclear -very safe- reactors are demonstrated and deployed.

Ther has been a lot of noise about fuel cells in the last 5 years but little progress. OIl&Gas companies could help accelerate the development of Solid-Oxide fuel cells (SOFC) since the possibility of using hydrocarbons directly into the cell without the need of reforming. SOme automakers are developing stationary fuel cells as a mean to learn on how to produe the transportation version.

You seemed to have "missed the boat." As one of the founders of the PV industry in the U.S. and one of the first marketers of fuel cells, I must say big business has kept both these technologies "under wraps" for years. I found a solution; producing hydrogen "on-site" via gasification in a very successful process utilizing many waste streams. There is a technology out of Switzerland that is ready for the marketplace. The secret is waste, both toxic and non toxic which can be converted into hydrogen to power fuel cells, microturbines, recips and the like. Like killing "2 birds with 1 stone." I will be pleased to share this with all. Contact me at salamays@bgallc.com. The future is bright; you just have to look carefully and keep it away from big business interests, especially the oil industry, which is why PV and FC's are still years away from making a dent into the energy industry.

The next thing to do is to forget the 'massive infrastructure' of central generation. With onsite H2 generation, you now have a use for any excess electricity you generate and can use a DG system that produces baseload power onsite. The difference between a constant output at peak usage levels and the average power used per residence is surprisingly close to the power needed to run the average family's auto. (when using Vincente's 62.5% conversion factor above and the energy content of H2).

Using CSP to make your power provides for all domestic heating needs with built int CHP (Combined Heat and Power). Systems are even being designed to store cold as well as heat. All these new systems derive their energy from a point in the system early enough to eliminate the additional energy conversions you reference. Since each reduces the electrical load, this leaves more for H2 for the cars.

The nice part of this is that if designed correctly, no central utilities are involved except for those wanting redundancy. This not only eliminates your electrical costs and natural gas heating costs, but all the associated taxes too. Gotta love that part. :)

To those who say this isn't possible, consider this. Statements fortelling future PV improvements have not changed much in my 30 years of watching. New nuclear developments (including small safe reactors) aren't much different. Those two have quite a bit of funding behind them while CSP has none except for a few very large scale test plants. Even without the big grants, these Zero Net Energy homes are just hitting the market. Theyare still way too expensive now but the good news is that they have the highest potential for economies of scale to make them economical. I think it's time to start giving CSP the benefit of the doubt and say "when" not "if".

http://www.beyondfossilfuel.com/hydrogen/reynolds.html

"Since 1987, many European countries have abandoned the use of nuclear energy" and since 2001 many have reversed their previous stance and are now looking at the newer designs, with a view towards revitalizing their moribund nuclear industries.

(a) Peak Oil is anybody's guess. Libya and Iran are under explored and under drilled; and hence have not peaked yet. (b) You are very right in your observation that most small firms who made break-through in renewable were acquired directly or indirectly by Big Oil! (c) Everything on this planet is renewable - it depends on which time-scale are we talking about - 10 years, 100 years, 1000 years or a million years. (d) On the nuclear front how come you got it all wrong? More people die every day on road accidents than the combined death toll of all nuclear disasters (including Three-Mile Island, Chernobyl and the Monju) in history. Most countries hesitated to continue with their nuclear program due to the campaign led by educated derelicts who thought “small is beautiful” and “renewable can substitute the fossil fuel, hydroelectric and nuclear energy”. We may be able to run a car with hydrogen; but can we produce either the car or the hydrogen with out conventional fuel/power in the foreseeable future?

I like to reiterate in these columns, that oil and other fossil fuels can be effectively substituted only with NUCLEAR POWER, which is a commercially proven technology that can produce electricity in abundance; and it is already late to accept that as of now ONLY NUCLEAR energy can meet the energy requirements of the world in the near future. We all should work for more global cooperation and standardization in nuclear power generation which could make it cheaper, safer and faster to build. reji@rejikumar.com

Charles: Thank you for confirming my prediction about nuclear fusion power.

Dennis: I believe you are assuming that Solar-Hydrogen Economy will follow the SAME path that Petroleum Economy, i.e. centralized distribution. The S-H Economy will be one of de-centralization where hydrogen is produced at the user site. Remember, the solar energy source is free for generating electricity, i.e. solar-Stirling engines or PV cells. But, the energy needs to stored. Hydrogen is the best solution for storing the energy.

Vicente: See my forthcoming part 2 of this series at "energypulse". On an equivalent energy basis, it is cheaper to move hydrogen 1,000 miles and then burn it to recover the energy than an equivalent amount of electricity (transmission losses). "Cracking" of natural gas to hydrogen is now done at refineries but requires a high temperature over a catalyst. This high temperature can be generated by solar or burning of natural gas with increasing the gas price. No, the best way is for local "point of use" generation via wind or solar power to generate hydrogen, e.g at home or filling stations. . There has been over 100 stationary fuel cell energy generation systems placed worldwide at such locations as airports.

Vicente: Pyrolisis or gasification at high temperatures of waste requires energy input to maintain the high temperature. Then, the hydrogen must be separated from the other gases. No, this is too an energy intensive process. Electrolysis of water is still the best currently available technology particularly if one uses the free energy of the sun to generate electricity.

Todd: Hydrogen is just a storage vehicle for electricity at night. As far as CSP, yes, solar-Stiring engines are more efficient than PV (35% vs. 17%) for conversion of sunlight into electricity. Yes, you are correct, the Solar-Hdrogen economy is one of decentralization, i.e. "on site use". By the way, the DOE's program of generating hydrogen via thermal process at a nuclear reactor is a recipe for disaster. The Chernobyl incident was caused, in part, by a hydrogen explosion.

Dr. Warren Reynolds, the author

Thermochemical H2 production, which is significantly more efficient than electrolysis (50-60% vs. ~30-40% H2 out vs. heat in) will be used to make H2 for large scale (co-located) users, such as refineries or synfuel plants. H2 will be added to carboniferous feedstocks such as heavy sour crude, tar sands, biomass or coal to make light (high H2 ratio) liquid fuels. These will be used in ordinary, hybrid, or plug-in hybrid cars. It is clear that gasous-fueled (e.g., H2 fuel cell) vehicles will never stand a chance against plug-in hybrid and/or pure electric cars. The writing is already on the wall.

Better to use home/solar generated electricicty to just power the home, or perhaps charge a plug-in or electric car. Using power to make H2 and then converting the H2 back to power (using a fuel cell) results in losing almost 2/3 of the initial power, and involves a lot of expensive equipment. Better yet, I think Todd is right, and we should focus first on using solar for residential heat.

Mr. Reynolds doesn't seem to think things like overall process efficiency matter much; after all the energy source (sunlight) is "free". I beg to differ. At least as of now, solar is the most expensive energy source out there.

Peter Platell Sweden

Solar provides heat which is the easiest form of energy to collect and store. Since Stirlings are the most efficient at converting that into shaft/electrical power, they can be used to make domestic electricity with only two energy conversions. The system efficiency of this process can top 40% on the drawing boards today and should top 50% in the near future. However, this efficiency doesn't matter as much since the fuel is free and the 'collector' is the cheapest piece of equipment in the chain.

The lower temperature 'waste' heat from the Stirling is still at a high enough temperature to be used for other domestic needs. This energy comes at a price of no energy conversions, or 90+% efficiency.

Since the average usable solar energy on a given rooftop is much greater than these two needs, we can get our transportation needs met here too. Scaling our system up, we can either raise the quantity of the heat or the quality (temp). Increasing the temp will raise the Stirling's efficiency a little, as well as increase it's fuel supply. This results in an imbalance where more electricity is created than is needed, for only the cost of more collectors. This electricity can either be sent to BEVs or used to make hydrogen. We do take another efficiency hit on making hydrogen, but the numerous benefits outway it if we choose that path. We can now power H2 vehicles, PHEVs, H2 stoves (for the gas stove lovers in the audience) or even backup our original heat storage during critical outages.

Where to store this hydrogen? How about sending it backwards into our existing and no longer needed natural gas pipeline. It is my understanding that they can even mix to a 20% H2 concentration before any appliances need much alteration during the transition period. This pipeline with it's large volume can store vast amounts of hydrogen at pressures as low as a few PSI. This is still higher than the regulators need for domestic use. Pressure imbalances between neighborhoods/towns/states, will automatically force the gas to the more needy areas. Piped hydrogen now becomes the energy form transferred between the bartering regions.

Pressurizing the stored gas for vehicle storage requires a compressor. This is where market forces drive the decision. You want fast home fueling, you buy a big compressor, otherwise it takes all night or you go to a fueling station to fill your vehicle's tank. Using the hydrogen in your vehicle can be done with fuel cells or internal combustion engines, but only external combustion engines have the ability to recouperate the energy used in compressing it to tank pressure. Also, external combustion allows for a continuous burn which can eliminate NOx emissions.

Since all of these processes are local to the site, there are no associated transmission losses, no pollution, no land mining and no expenses for transport. Department stores with large roof areas and low energy needs would be a net energy producer while factories have the opposite situation. There are no toxic materials involved and governmental regulations are at a minimum. The entire system is a one-time capital only purchase that can be integrated into the home loan with maintenance performed by medium skill level local labor. My current cost projections are that the payback would be around 20 years and expected to drop from there. My personal goal for this is to reduce the ever growing portion of our income that we spend on energy.

I'm not a believer in the future of hydrogen for transportation. However, one can make a case that when fossil hydrocarbons become too scarce and expensive to use as fuel, the most efficient solution for producing fuel on a large scale from renewable energy sources is hydrogen. It will never be as efficient as batteries for short range personal transportation, but even as bad as current hydrogen storage is, the system gravimetric energy density for hydrogen + fuel cells + storage is still significantly better than for batteries. And, presumably, a hydrogen-fueled vehicle can be refueled a lot faster than a battery-powered vehicle can be recharged.

There are flaws in that argument, but I'll leave to you and others the fun of picking it apart.

A mature industry (in say 5-10 years) won't have this problem since they will be operating with actual accountability.

"half the cost per kilowatt-hour and one-tenth the weight of lead-acid batteries."

"* The batteries fully charge in minutes as opposed to hours.

* Whereas with lead acid batteries you might get lucky to have 500 to 700 recharge cycles, the EEStor technology has been tested up to a million cycles with no material degradation.

* EEStor's technology could be used in more than low-speed electric vehicles. The company envisions using it for full-speed pure electric vehicles, hybrid-electrics (including plug-ins), military applications, backup power and even large-scale utility storage for intermittent renewable power sources such as wind and solar."

Sources of questionable reliability at eg. http://tyler.blogware.com/blog/_archives/2006/1/19/1715549.html

Paul: I know of no information that shows the European countries have voted to revitalize their nuclear industries. On the contrary, the Euorpean Commission on Sustainable Energy is leading the campaign for 100 European communities to meet 100% of their energy needs via renewable energy. Nuclear power is not a renewable energy since there is a limited supply of uranium.

R. Rejikumar: Thank you for your kind comments. you are right. Peak oil is the geologists assumptions and guesses.

As an ex-nuclear engineer, I know the nuclear problems first hand from their atmospheric release of radioactive gases (tritum, Kr-85, Xe-133) to breeder reactors and the nuclear waste problem. It is not the death toll we are dealing with but the widespread contamination. A Government report shows that the cancer rate has tripled downwind of the Chernobyl incident due to people eating radiation contaminated food and receiving air-borne radiation. Large areas downwind are also uninhabitable due to the radioactifvity.

James H. The decomposition of water to hydrogen and oxygen requires 56.7 kcal/mol. The efficiency of direct thermochemical decomposition of water at high temperatures varies with the temperature. At 2,000 deg.C, it is only 2%, at 6,000 Deg. C, it is 49%. So the helium would have to be quite hot to even begin to reach your quoted "50% efficiency". There is R&D on the photocatalytic decompositin of water at low temperatures but it is of low efficiency. You can decompose water over a platinum catalyst at 200 deg.C but would require large amounts of platinum (>$800/oz) to generate the massive amounts of hydrogen needed. Researchers at UCLA have patented a chemical process recently to decompose water at 900 deg.D

Currently, at refineries, large amounts of hydrogen are generated by reacting natural gas over a catalyst with steam at 1,000 deg. C. it is energy intensive but could be done with solar or by heating with natural gas itself.

Pure electric autos are a dead issue due to the re-charge time vs. hydrogen filling time. Hybrid gas/electrics are just a "stop gap" until the fuel cell vehicles are commercially viable.

The author

Why? Because Hydrogen provides the most efficient method of storing energy for only a narrow niche of applications - namely, those applications needing to store energy 3-7 days (roughly) from when the energy was initially provided. For applications shorter than this, battery or capacitive storage is more cost effective.

For applications longer than 7 days, then conversion to methane via Sabatier reactor makes more sense.

Reasonable people can debate the timeframe; it may be as little as one day on the low end and as long as 14 days on the high end, but hydrogen is definitely "pinned" between some kind of electrochemical storage and synthesized methane. This means that any technical advances in batteries, energy collection, etc. will only narrow this 'tween' area further. Hydrogen fuel applications are on a tiny island that can only sink further.

Conveniently, a methane (or natural gas) pipeline infrastructure is already in place, as is the electric grid.

So, build plug-in hybrid vehicles than run on methane. That is the easiest way (at least for vehicles) to make use of renewable energy sources.

I agree with everything you said except that I'd change the word "methane" to "methanol" (that's the liquid hydrocarbon with the highest H/C ratio, isn't it?). With plug-ins, the hydrocarbon fuel will only be used for ~15% of the miles (or overall energy use). For this purpose, a high H/C liquid hydrocarbon fuel, generated from biomass sources or some other synfuel process, will suffice. The whole gaseous fuel thing, and the associated equipment, difficult procedures, and infrastructure, is not worth it. Let's just use our existing liquid fuel and electric power distribution infrastructures. Liquid-fueled plug-ins can be introduced seamlessly.

I acknowledge that methane would be better than any H2 scheme, due to the existing gas pipeline infrastructure, but still.... Besides, we should be thinking of ways to use less natural gas, not more, givin this continent's diminishing supplies. I suppose there might be ways to make synthetic gas, from coal or biomass sources, but those methods could just as easily be used to make a liquid fuel.

I fail to understand why simply plugging your car in at night is such a problem. It's actually less of a hassle than going to the gas station, as it takes less time and you don't have to go somewhere to do it. The "fuel" cost per mile will also definitely be a small fraction of what hydrogen would be. The only potential problem would be if you forget to charge, or if you're on a long trip. The plug-in (as opposed to pure electric) car solves all such problems, as it simply becomes a normal (~50 MPG) hybrid when the batteries run dry.

There are no issues associated with plug-ins that warrant investing trillions in a new H2 distribution and fueling infrastructure, or going with a (H2/fuel cell) system that has ~1/3 the well-to-wheel efficiency of the electric/plug-in car approach.

Concerning thermochemical H2 production, helium gas output at 900 oC can produce H2 at over 50% efficiency. At 1000 oC, the efficiency approaches 60%. "Hybrid" approaches that combine high temperature heat and electrolysis can attain similar efficiencies at lower peak outlet temperatures. Perhaps you're not accounting for the fact that the process will make use of (abundant) catalysts such as sulfur and iodine.

Using heat to generate power, and then using the power for electrolysis, is much less efficicent (~30-40%). Shipping H2 gas from central generation plants to end users is so expensive and involves so much energy loss, however, that I agree that electrolysis near the point of use will be the method used if H2 were to be used to power fuel cell cars. The point is, though, that it never will be. H2 will be generated, mostly by thermochemical processes, but that H2 will be used as feestock to create very light, "sweet" liquid fuels from heavy-carbon feedstocks.

BTW, as far as the "insumountable" range problem is concerned, have you all checked out this site for a new car company called Tesla Motors? W/o any help from the govt., they have developed, built, and are marketing a pure-electric sports car with a 250 mile range. Its performace (speed, acceleration) is equal to or better than a standard car. And note that this is with today's batteries, a technology that is advancing extremely rapidly. A ~400-mile range, as well as significantly lower cost, is only a few years off. And if this doesn't meet your needs, there are always plug-in hybrids.

www.teslamotors.com

Westerm nuclear plants have never had any measurable effect on public health over their entire ~40-year history. Meanwhile, fossil plants are known to cause ~25,000 premature deaths every single year in the US alone. Even a worst-case meltdown would not have anywhere near that effect. Similarly, the risk from nuclear waste was, is, and always will be negligible compared to the risks from the toxic materials released into the air and dumped into the ground by fossil fuel plants.

There is no comparison. The public health and environmental risks from nuclear are negligible compared to fossil fuels, and roughly similar to those of renewables. Those who doubt this should look at the results of the most exhaustive "external cost" (i.e., public health & environmental cost) study that was performed by the European Commission, whose results are summarized at:

http://www.externe.info/

James, are there any updated studies from ExternE that include CSP or solar thermal electric? Except for minor installation or maintenance accidents, I can't see a single category with any external costs that would apply to CSP.

Oh, and regarding Tesla Motors' electrics, they're really nice, but it'll be a few years yet before I can afford the $100,000 price tag.

Yes, but H/C ratio doesn't tell the whole story. The oxygen atom in methanol means some debatable but nonzero fraction of the hydrogen in methanol has already been burnt. Thus methanol's free energy of combustion is 21.39 MJ/kg. If you want minimum local CO2 emissions per joule of combustion free energy from a room-temperature liquid hydrocarbon, I think that hydrocarbon is propane under its own modest vapour pressure. It yields 47.35 MJ/kg. Not that dense fuels need yield any CO2 at all, of course.

--- G. R. L. Cowan, boron combustion fan
how motoring gains nuclear cachet

Yes, efficiency does matter. See my oil-well-to-wheels efficiency numbers in my Part 2 of this series.

Peter: Yes, hydrogen/internal combustion engine (ICE) technology is already here. Ford has built an engine specifically for hydrogen in 2003. It has leased a number of these hydroge-ICE buses to Florida and other parts of the U.S.

Todd: Thank you for your excellent comments. My Carnot thermodynamic efficiency calculations for the Stirling engine show between 30-40% dependent on the absorbed temperature. There are developments to extract the "waste" heat from the Stirling using semiconductor thermoelectric converters that will bring the overall efficiency to 50%.

The author

Again, reasonable people can debate this either way. Methanol is favorable because it is liquid. Almost everything else is less favorable. It is very bulky (2X the bulk of gasoline w.r.t. energy content), its kind of dirty to use, and it's quite poisonous.

Actually synthesizing methane (or methanol) from renewable sources is quite difficult and expensive, compared to what we are used to be paying for gasoline or natural gas today. (But these are causing GW and are also finite resources, so I guess we are paying at the back end.) One can use biomass, but there isn't enough of that, so let's stick with the hypothetical synthesized methane or methanol.

In either case, you need CO2 feedstock, captured from various possible sources. You need it and you also need to store it, because it's not likely to be captured when energy is available. To me, this tips the scale to methane, because you would need a CO2 storage infrastructure as well. Since this could at least partially double as a methane storage mechanism, but not so well for methanol storage. (And it would be too costly energetically to convert methane to methanol as a second step.)

Again, reasonable people can debate methane vs. methanol. Not nearly so true when debating the merits of hydrogen vs. almost anything else.

Todd: NiMH batteries are quite recycleable. As are Li-ion, for that matter. Yes, methane/methanol does emit CO2, but that is compensated by CO2 that must be captured for input to the production process. The easiest (benign) place to get it would be from biomass processing plants, such as ethanol or even methane from biomass. Both produce lots of CO2 that is simply vented now. (Brazil produces lots of capturable CO2 from all their ethanol production.) You can also just snag it from the air but that tends to be more expensive or time-consuming, or both.

Graham: Yes, you are right. I never much like the H/C ratio thing. The energy is in the BONDS, not the atoms them selves. My internal thinking regards -OH radicals as essentially non-energetic. So methanol (CH3OH) has basically 3 H-C bonds in it. An H-C bond has about 80% of the energy of an H-H bond.

One can make a heirarchy of sorts: H2O, CO2 (no bonds, but CO2 is more energetic than H2O) H-H, CO (1 bond) CH2O (2 bonds in an impossible molecule, because you can't put 2 Hs and 1 O on a single carbon, at least in any stable way. But the ratio CH2O is that of plant matter (glucose, cellulose, etc.) This is biomass. CH3OH (3 bonds, methanol) CH4 (4 bonds, 3.2 times energetic than hydrogen gas on a per molecule basis.) Higher alkanes (Every hydrocarbon larger than methane becomes a bit less energetic on a per mass basis, but becomes easier to handle as they become liquid at higher temps and lower pressures. Only alkanes (single carbon-carbon bonds) store energy as efficiently as possible for the number of carbons used. That's why refineries use so much hydrogen: they hydrolyze alkene and alkyne bonds to create staright alkane products (heptane, octane, decane, etc.)

James: I have read your reference: www.externe.info and it is directed toward fossil fuel and its environmental costs and effects (see Impact Category). Nowhere does it mention the nuclear costs. If one were to include the cost of nuclear waste disposal, our electric rates would be $0.80 per kwhr.

Since it takes energy to separate bonded atoms, bond energies are conventionally considered negative.

--- G. R. L. Cowan, boron combustion fan
how motoring gains nuclear cachet

Jim , I think high temperature storage is a better short term storage than electric batteries but there is of course only steam engine that can make use of such heat.

Len , yes waste disposal is included in our electric bills, and still there are no country that has succeed to find a long term storage solution, Nobody wants to have the waste at their backyard.

I'd suggest putting the effort into Stirling cycle, also external combustion, if external combustion is the goal.

Room-temperature liquid fuel is better than hydrogen, but not, in my opinion, as good as room-temperature solid fuel.

--- G. R. L. Cowan, boron combustion fan
100 watt-hours in a baby's fist

Peter, with a high side temperature of 450C, a Stirling could approach the Carnot efficiency (58%) the closest. Also much safer than bringing back boiler explosion potential. With the energy available from a trough (~200C) as you suggest, thermal storage (via heat of fusion) would best apply for safety, economics and energy density, and would still convert to electricity approaching 40%.

Jim, what cost is there on the infrastructure required (full life cycle) to support biomass as opposed to just plugging in an electrolysis box in one's garage? Remember this has to apply to hundreds of millions of cars in just this country alone.

One problem with alcohol (ethanol) production from biomass is the separation from water that is needed. This takes quite a bit energy. It doesn't have to be high quality energy, but it is needed. Think of the fire under the backwoods still.

If I recall correctly, methanol can be produced directly by heating wood products in an oxygen-free environment. Something like that. I think they call it pyrolysis. You can also make it easily from methane, but that defeats the point, as we are already facing NG shortages.

Methanogenesis uses microbes to produce methane from biomass. Since methane is a gas, there is no problem with separating the water, but you do have to separate it from carbon dioxide. This is less energetically taxing than alcohol/water. This process takes place in many of our landfills, which are often tapped for this purpose.

I think this article (and many of the comments) are emblematic of many of the discussions here. Many recurring themes are played out:

1. The policy wonk advocates hydrogen. Hydrogen is universally dismissed by the techies, who then argue amongst themselves about which (non-hydrogen) fuel is optimal. I'd like to find the organization that keeps churning out the hydrogen advocates, and set them straight. When I went to a hydrogen conference and confronted them directly, they just turned away, mumbling. Hydrogen is a paper tiger that is finally starting to shred.

2. The nuke vs. no-nuke debate. The pro-nukes point out that lots of electricity can be made with no GHGs. The anti-nukes point out that the waste problem is not solved. The pro-nukes say that it is, etc., etc.

3. The tailing problem. This is a little harder to explain. Basically, in addressing our energy problems, one is motivated to provide a complete solution, but the final pieces, or tail end, rarely makes economic sense. So one could end up acting foolish. For example, what fuel should a PHEV burn? ethanol? methanol? methane? If we assume that the electric portion of the PHEV provides 80% of its energy, then the vehicle is running on only 20% of the fuel previously needed. At that point, it doesn't really matter. Gasoline is fine! Going for the 100% green or renewable solution can lead one to somewhat ridiculous places.

4. The grid. The grid acts quite irrational for the small producer. Heck, it acts irrational for energy conservers. (There is an article about this too.) So do you do work on something that caters to the grid as it is, or as it SHOULD be? This can be a stupefying problem.

In a perhaps lame effort to chop this Gordian knot, I'd say to Mr. Reynolds that his focus should not be on hydrogen (wrong, just wrong) but on the independence that solar or other decentralized energy choices can provide. If you ask the typical American if they'd like paying $4 a gallon for gasoline, they'd say "no". But if you ask them if they TRUST the government, TRUST the utilities and nuclear power plants, and TRUST the oil-producing countries to provide us with cheap oil ad infinitum, they'd say "Hell, no!". And then if you asked if they'd be willing to make some changes, not huge ones, but changes to their energy use such that they'd be independent of these entities, they'd say "Hell yeah! Sign me up!"

Carnot efficiency is of course the fist step to considered when discussion different power cycles. The next step is to take into account the physics for a certain working fluid. If you do that for gasoline, diesel, Stirling, Brayton cycle you will end up with some conclusion. The next step, when try to implement the isoterms, isentrop etc. in hardware it will end up with some consideration about mechanical efficiency and specific power (kW/volume,kW/kg) Everyone little familiar with thermodynamics knows that “carnotizing” and fully expansion will give the highest efficiency. However, we also know that all types of power cycles except fuel cell and steam engine has the highest efficiency at high load (despite uncomplete expansion). That can be explained if study the indicated work (or mean effective pressure) normalised to inevitable friction losses. Then you will see that engine concept as (virtual) Carnot engine will have very poor specific power and low efficiency when taking friction losses into account. Stirling engine is some kind of “Carnotizing” and suffer also from low specific power and real efficiency is far away from pure isentropic and isoterms consideration and not including preheating of the working fluid. A diesel engine is pretty alike a steam engine when you considered mean effective pressure normalised to maximum pressure, which explains the relative high part load efficiency for a diesel engine compared to a gasoline engine (gas exchange work also means a lot) The reason why my father started to work on Saab was the high part load efficiency that could be achieved ( 30 % at 100 (250 bar) and +450 C) , We have verified almost everything except the expander proper. It has to operate without oil and run at high-speed , 5000 rpm (compared to old steam engine) . We are now involved in a EU project regarding a small scale Combicycle” where a 25 kW steam engine system act as a bottoming-cycle. In stationary applications weight is not a big issue. Our technology however is aimed for automotive applications and specific power, air cooled condenser etc. means quite different specifications. We are involved in a R&D project at Royal Technical Institute of Stockholm, “High Tech Steam Engines for automotive applications” with the goal to built a 2 kW/kg complete system with an efficiency if 32 % at part load. That means 3 times less fuel consumption compared to an internal combustion with the same peak power operating during normal driving cycle and in the same order of magnitude as fuel-cells ( with lower peak power).

Built such engine is not difficult from efficiency and specific power point of view. However, lifetime with an oil-free high speed reciprocation engine is another issue. New material unfold attractive tribological conditions but without cleaver mechanical designs that balance forces it will be very difficult to obtain an acceptable lifetime. But we are at least confident to have such a solution and there are also other companies in US and Germany that is developing new steam engines. But I am still confused that there is so much interest in fuel cell and so few looking at steam engines. Our solar collectors partner say they can built (small on the roof) parabolic through for 150 US$/kW that is producing 450 C steam. That steam is then stored in a patented Steam buffer (sensible heat in ceramic material) with an energy density of 100 Wh(heat)/kg and 10-100 kW/kg for some hours ( 2-10 hours). Jim I think you are pointing exactly right when you say that focusing on hydrogen leads wrong. The focus should be on harnessing the infinite, diluted, dispersed and stochastic renewable. It takes surfaces, but the surfaces are there, distributed on building envelopes all over the world. For instance producing alcohol takes energy for separating water. But the solar energy is there (some hours). Let us produce the alcohol when the sun is there . Then we have a energy carrier which is easy to store.

The nature of law will force us from large centralised business model requiring high density fuel (fossil and nukes) toward mass produce small-scale technology and business models fitted for different regions. ?

<..> Hydrogen provides the most efficient method of storing energy for only a narrow niche of applications - namely, those applications needing to store energy 3-7 days (roughly) from when the energy was initially provided.

<..> hydrogen is definitely "pinned" between some kind of electrochemical storage and synthesized methane. This means that any technical advances in batteries, energy collection, etc. will only narrow this 'tween' area further. Hydrogen fuel applications are on a tiny island that can only sink further.

- Jim Beyer 10.1.06

I don't think those are likely developments, and of course the competing solutions won't be standing stil. But I wouldn't rule it out entirely.

Roger: I think you may be surprised at the energy-to-mass ratio of the newest supercapacitors. Plus recharge as fast as you can supply the electricity, and no degradation of performance after 1 million cycles. Name is EEStor, very little currently available.

"half the cost per kilowatt-hour and one-tenth the weight of lead-acid batteries."

- Len Gould 9.29.06

As to "recharge as fast as you can supply the electricity", that part I have no trouble believing; it's true of all supercapacitors. And it's exactly the problem: you just can't supply the electricity all that fast. The average home is only wired for about 8 kW, max, with individual circuits around 1.5 kW. There's no way you're ever going to recharge a 15 kWh battery pack in less than a couple of hours--short of paying a bundle for the utility to rewire your home for industrial service. To do it in only minutes means hundreds of kilowatts, and your own dedicated power substation.

There's a solution, however: sets of swappable battery modules.

The efficiency of direct thermochemical decomposition of water at high temperatures varies with the temperature. At 2,000 deg.C, it is only 2%, at 6,000 Deg. C, it is 49%.

- Warren Reynolds, 9.30.06

Go to the bottom of the page I linked. You will see a summary table giving the overall external cost, per kW-hr, for all major energy sources, including coal, gas, nuclear, and the major renewables. The table shows that the total external cost for nuclear is a fraction of a cent/kW-hr, more than a factor of 10 lower than coal or oil, and similar to renewables. This includes all issues such as repository risks, plant accident risks, uranium mining effects, etc... Any "Price Anderson" subsidy is included, in the accident risk part. It all doesn't amount to much.

Concerning waste, all costs are fully paid by a 0.1 cent/kW-hr fee that is already included in the cost of nuclear electricity. Not only are you off by a factor of 800, but you were worong to suggest that it's not included in the current price. Nuclear is the only major energy source that fully pays all costs of permanently isolating all its waste products from the environment. Others freely pollute (causing massive health effects), and they do it for free. If coal had to pay compensation for its pollution effects (as nuclear would in the event of a severe accident - hence the need for insurance), its price would more than double, and all the conventional plants would shut.

Concerning biomass fuel vs. home electrolysis, I would agree with Jim Beyer. We mustn't let the perfect get in the way of the good enough. WIth plug-ins, ~85% of the energy usage is from pure electric power; power that is utilized at a much greater efficiency than any H2-based approach. For the 15%, heck use oil. Cutting oil usage by 85% is nothing to sneeze at. Either that, or generate the liquid fuel from natural gas, biomass, or even coal. Go ahead and apply a CO2 tax. Economics will sort out which one is chosen. This solution is beyond good enough, for the first half of the century anyway.

I would argue that even if oil or coal-based synfuel were used, the overall environmental effect would be less than the H2/electrolysis approach, due to the fact that the H2 approach would require ~3 times as much input electricity. You can't minimize the importance of this. One thing is for certain though, the cost (per mile) of electrolysized H2 will be much higher than the cost of any liquid fuel, even with any "infrastructure costs". Note again, that whereas your H2 has to provide all the miles, this liquid fuel only has to supply 15% (and we KNOW that simply using electricity directly for the other 85% is far cheaper than using electrolysized H2).

Once again, here's an idea. Let's just tax or limit air pollution, CO2 emissions, and energy imports, and then let the market decide (i.e., wait and see what happens). I am perfectly willing to be wrong (I won't get that upset).

Folks who use Kr-85 and Xe-133 for instrument calibration and the like are regulated by state as well as federal agencies. For example, California and 10CFR20 (Appendix B, Table 2) have established effluent concentration limits for Kr-85 and Xe-133. These limits along with as low as reasonably achievable (ALARA) considerations allow a typical California nuclear facility that uses a standard exhaust hood to safely release Kr-85 at 1360 microcuries/day and Xe-133 at 820 microcuries/day. For those who seek, admittedly, less hysterical information on why these levels are safe, National Council on Radiation Protection (NCRP) has published report Nos. 1 through 121 (as of 1995). Reports date back to 1951, over five Kr-85 or Ba-133 half lives ago. Last time I looked, NCRP annual meeting proceedings, memorial lecture transcripts and council commentaries were also available.

How in the world did we get so far from discussing much-needed renewable energy research? Maybe as Doc Glasstone once observed, "The chief terrestial sources of energy, namely, coal, oil, natural gas and water power, are actually stores of energy originally derived from the sun. Consequently, although it is not generally appreciated, nuclear energy is indirectly supplying the world's power requirements."

This really points out how moribund the grid operators really are. They should just pay the darn 10 cents or whatever. Statistically, it won't cost them much, and may encourage more homeowners to generate their own power which will decrease the utility's number of pesky, unprofitable customers and stabilize the grid as well.

The only 2 cent (or less) generation out there is that coming from already-built nuclear plants and hydro dams (and windfarms perhaps). Even coal plant's operating costs are over 2 cents now, with the higher cost of coal. And this doesn't cover the capital costs of these high-construction-cost, low-operating-cost plants. If anyone sold you such power for 2 cents, they wouldn't be getting anything for their initial investment. Thus, I don't think your 2 cent cost figure is really fair. In short, electricity costs more than that. (And I didn't even add in distribution (grid) costs).

But these power cost issues are not even the central point. You're talking about taking this electricity and using it to make H2 for a fuel cell car at ~33% overall (electrolysis + fuel cell) efficiency. My question is, why not use that same electricity (whatever its cost), and just use it directly, to charge an electric or plug-in hybrid car, at an overall efficiency of ~90%. With the 2nd approach, you get 2-3 times as many miles out of the same input electricity. Furthermore, you don't have to buy and operate the expensive home electrolysis equipment. Or gaseous, H2 compression/fueling equipment. Finally, a fuel cell car is much further out technologically and, if anything, will be much more expensive. This is an economic no-brainer, barring some intractable problem with electrics or plug-ins, conerning which I would say......

Nobody has yet given me any convincing arguments about what the downside is of simply recharging your car at night with off-peak electricity. Forgetting to charge and/or long trips are simply not issues for plug-in hybrids. The small amount of liquid fuel that is used can be produced using sustainable methods (i.e., using renewable feedstocks, or feedstocks that have an abundant, long-term domestic supply). It'll be good enough, for a few centuries anyway.

However, there are other considerations regarding the price of purchased electricity via various techniques. If you have a DG system with CHP built in, you pay off that capital expense with both the electricity dollars saved and heating bill savings. Without monthly transmission costs or taxes, you add to this effect. By now you can justify upgrading the system to provide increasingly larger portions of your transportation energy. Hopefully it should be clear now how such a system could in fact, cost less than 2 cents per kwh in the not so distant future.

Your point is correct about using the electricity to charge a PHEV first, but when considering the storage benefits for a home DG system, making onsite H2, even at lower efficiencies, has merit. You don't want to waste any excess electricity made and you sure don't get your money's worth when reselling to the grid. The nice part is that stored H2 can be backup energy for either home or auto.

Ah, now I understand the 2 cent reference. Sorry.

I must say I'm shocked by the stingy utility policy you describe. If we're talking about solar PV systems (which is almost always the case, as of now), they generate power near peak times, when natural gas fired plants make up the incremental capacity. Given this, the avoided fuel cost alone is at least 4 cents (based on ~$6/MBTU), or significantly more than that if gas costs more or if non-CCGT plants are being used for the incremental power (often the case at peak times). And I'm not counting any grid relief that would come from a distributed generation souce at or near the point of demand. This should be worth another couple cents.

This policy varies by state. I think that here in CA, the utility has to pay full retail (not wholesale!!) price for the power sent back (i.e., over 10 cents/kW-hr). The meter literally runs backwards.

I would say again, however, that using it to make H2 would be one of the least useful things to do with such excess power. Not only should one charge a PHEV first, but barring that, the power should be used to help meet peak grid power demand. The fact is that peak-time grid power being generated when such PV systems are at peak output costs a whole lot more than 2 cents to generate. This power is desperately needed to relieve peak demand on the grid, and to displace generation from old, inefficient, gas/oil-burning peaker plants. If utility policies concerning power buy-back to not reflect these realities, or result in the excess distributed power being used in the most rational way, those policies need to be changed.

If instead of solar, your home has a small wind turbine that usually generates power at night, then I dunno. Even then, I'd probably suggest trying to store the power for peak usage, using some method of storage other than hydrogen. My understanding is that in terms of simply trying to store electric power use at a later time, hydrogen ranks dead last in terms of cost and/or efficiency. Use batteries. Use compressed air. Use a flywheel or even a big spring. Use anything but H2! Perhaps I'm wrong....

Regarding H2 generation, I agree that one should first charge a PHEV. No question about that. But if a PHEV only holds 5-10 kw-hr, what do you do after that? The problem with batteries is that you can quickly overwhelm your storage capacity on some days, if your system is sized to provide your nominal power requirements on typical days.

The crux is that H2 (or other products like methanol or methane) are grossly inefficient to synthesize, but ridiculously cheap to store for long periods after doing so, at least with respect to batteries, compressed air, flywheels, or any other non-fuel type of storage. So I don't think you are wrong, per se, but your budget would break if you purchased all the batteries, etc. needed to store your excess power.

--- G. R. L. Cowan, boron combustion fan
how motoring gains nuclear cachet

Well, I don't care much for H2, so let's see what methane would need. (But I will get back to H2 anyway)

16 grams (1 mole) of methane under 150 psi, would require about 2.27 liters. So a 500 gallon steel "pig" (normally used for propane) could hold 1895 liters or 13.356 kilograms of methane. A steel pig like that runs about $1000-$1500 or so and they can last a long time (20+ years).

13.356 kilograms of methane x 15.5 kwhr/kg equals 207 kwhr of energy. Assuming a 25% electric conversion efficiency (www.marathonengine.com) then you'd have about 50 kWhr of storage in a single pig. 1000 kwhr would thus require about 20 pigs or $20,000 to $30,000. A single larger pig (10000 gallons) could probably be bought used for about $10K.

Compare this with a low cost lead-acid battery storage of perhaps 500 watt-hours for $75 bucks. This would cost 1000x1000/500 = 2000 batteries or $150,000 ! And the batteries won't last 20 years, either.

If you used the tanks for hydrogen (and the fittings didn't leak) then you'd have about 3.2 times more tankage needed (64 tanks) but perhaps better efficiency with a fuel cell (40% ??) bringing you back down to 40 tanks (twice the volume). So maybe $40-60K for the H2, which is still much less than batteries.

I purposely used low pressure (150 psi) tanks because the available technology is very cheap. High pressure (3000 -10,000 psi) tanks are much more expensive and the costs would rise considerably.

So is $10-$20K ridiculously cheap? Well, you are talking about several weeks worth of a home's energy use, so I think so. Yeah. And definitely when compared with $150K worth of batteries.