Sunday, July 12, 2009

Planning for Post-Carbon Energy

In 2007, I set out to come up with a viable plan for post carbon-energy. I believed at that time that it was going to be necessary to reduce world emissions of CO2 by 80%. I was armed with the knowledge that finding a post carbon source for electrical generation and for transportation could eliminate up to 60% of fossil fuel use. I was not sure how much of that could be wrung out of transportation, but I thought that surface land transportation was promising. Brian Wang of Next Big Future had written advocating the electrification of rail transportation, and the elimination of long distance truck shipping. This would eliminate a great deal of fossil fuel use in trains and trucks for long distance transportation. It also struck me that by 2050, 100% of urban auto transportation could be powered by electricity stored in batteries or capacitors. Intra-urban shipping could be handled by battery and/or capacitor powered trucks, with perhaps a rapid recharge system. Long distance overland passenger travel could be handled by high speed electric trains. But longer distance travel was and still is a problem

Secondly there is the question of water based shipping. There did not appear to be a quick solution. Before the 19th century shipping distance shaping was wind powered. While the notion of returning to wind powered shipping is charming, it poses far too many problems to be practical. In fact the only potential power source would be nuclear. Would a nuclear powered shipping fleet work? I really don't know, but Rod Adams knows a great deal more about it than I do, and I get the impression that Rod thinks it would work. Maybe we can get Rod's comment here.

I did not see an easy solution for air travel. My father worked on the concept of a reactor powered aircraft during the early 1950's, but no one who was involved in the project at that time believed that it was going to be practical for nuclear powered aircraft, let alone civilian air passenger craft. The current air industry is dependent on fossil fuel derivatives for power, and there is no easy substitutes for them. Biofuel advocates say that it will solve the problem, but I had and still have reasons for questioning this claim. Bio fuels substitute carbon-based energy from current biological sources for carbon based energy from ancient fossil sources. The economic viability of this project is questionable. The energy economy of the bio fuel project is questionable. Finally there are long term questions about the effect of bio fuel production on soil. All things being considered he bio fuel approach gives us more questions the answers. The future of air transportation in 2050 is thus open to question, and I cannot foresee an easy technological solution.

So technological routes for replacing fossil fuels exist for surface transportation, and possibility for water based transportation, but air transportation is a problem,

When I looked at electrical generation in 2007, I briefly considered renewables. I formulated a few basic questions like, how would you produce electricity when the sun does not shine and the wind does not blow. Renewables advocates did not offer good answers to these questions. My exploration of the problems of renewable energy since 2007 has continued to yield the same negative conclusions. Renewable energy is unreliable energy. It is expensive to take unreliable renewable energy and transform it into reliable energy. I have explored the costs and will most likely will continue to do so, but in order to provide electricity on demand from renewable sources, we have to be willing to spend more that we currently spend for electricity. This, I felt was not desirable.

Compared to the cost of reliable renewables, nuclear power looked cheap, but still far more expensive than electricity generated from burning coal. There were other problems with nuclear power. It takes a long time to build reactors. Building a conventional reactor is in fact a mammoth construction project that can extend over a period of a decade. It was an open question to me whether enough reactors could be built world wide during the next 40 years to replace all of the carbon energy sources we need to replace.

If reactors could be built in factories, I thought. We could build enough reactors in 40 years to replace 60% to 80% of all CO2 emitting energy sources, but reactors are huge, and could not be transported easily from a factory to a power plant site.

Then I thought of the Molten Salt Reactor project my father had worked on at ORNL from 1950 to 1969. The MSR had a relatively small core, and in fact it was very simple. It could be built in a useful size at factories, transported by truck, rail or barge, and set up virtually anywhere. About that time I first encountered Kirk Sorensen's blog "Energy from Thorium." I though that Kirk was on the right track. And his concept was efficiently flexible to fit with my emerging vision. Kirk favored a thorium fuel cycle approach to which the MSR was admirably suited, and indeed my father had spent a good deal of time researching the chemistry of the thorium fuel cycle. The thorium fuel cycle offered the promise of a sustainable energy source. A source that could easily provide the human inhabitants of the earth all of the energy they needed for the next billion years or so.

The thorium variant of the MSR, which Kirk called the Liquid Fluoride Thorium Reactor (LFTR) was an extraordinarily promising concept. By conventional reactor standards it was very safe. Unlike conventional reactors it produced little or no nuclear waste. Like all reactors, the LFTR presented some proliferation issues, but those issues could be solved to the satisfaction of reasonable people. Finally a factory LFTR could be built at a price that was much lower than the cost of conventional reactors. Finally the LFTR could produce electrical energy more efficiently than conventional reactors. The LFTR was also a much more efficient consumer of nuclear fuel.

Thus the LFTR was potentially a major source of practical post carbon energy, a source which potentially could provide for all of the energy needs demanded by the human population of earth. By late 2007 it had become my intention to tell the LFTR story to anyone who would listen.


jimbo said...


It seems likely that instead of electrifying all transport, we will simply develop sythetic fuels via the Fisher - Tropsch process for example, using nuclear energy as a ready source of hydrogen. Carbon can be obtained by capture of coal fired sources, CO2 exhaust from cement plants or atmospheric capture. See for example, the 'Carnol Process' etc. It is a relatively easy syythesis to convert CO2 +H2 to either methane (natural gas) or methanol. Nasa built a working model methanol converter to use on a Mars mission running off of solar power , using the CO2 atmosphere as a carbon source.

Given abundant nuclear energy, making jet fuel, gasoline etc is not a problem.

David Herr said...


We can get to 0% CO2 emissions from surface, air, and water transport by using heat and electricity from MSRs to pull CO2 out of the atmosphere, and from there run an ordinary refining process to create synthetic fuels that will work in today's engines. This may require, over time, replacing current gas engines with diesel varieties, but the synthetic diesel from atmospheric CO2 will be sulfur free, and modern diesel engines are very clean and much more efficient than gas engines. If one injects small amounts of propane into the combustion chamber of a diesel engine, the pollution goes down even more, and the efficiency goes up. In this fashion, all transportation fuels can become carbon neutral, without requiring massively expensive replacement of current infrastructure. The extra MSRs needed will also provide a market for quickly disposing of "spent" nuclear fuel rods so that we can stop wasting time and money on Yucca mountain. Simply adding MSR modules to existing nuclear sites, and perhaps also existing coal power plant sites and existing oil refinery sites, will maximize the reuse of existing energy infrastructure, while dropping pollution to near zero. An added benefit is that our agricultural lands will be spared from the rapacious biofuels industry.

Alex P. said...

I think the easiest solution for non easily electrficable applications like ships and airplanes is to produce biofuel from "waste" agriculture crops (not necessarily corn) by LFTR heat and electricity. In the ethanol production, about 2/3 of the energy input is heat (more than half alone, indeed) and electricity, easy to produce with high efficiencies and in a cost effective way by LFTRs

Jim said...

Im a noob as far as this nuclear stuff goes, but loving it. I definitely agree from what I have read in the last few months that LFTR is the way to go, I wish we could get Washington to see this.

Your blog talked about powering ships with nuclear energy. When I read about Hyperion Nuclear Thermal Battery, I thought this would be perfect for ships. With a little searching I discovered that a large modern container vessel will normall have $2-3 million dollar fuel bill for a 28 day round trip voyage burning 217 tons per day of the dirtiest(cheapest) fuel oil out there. Hyperion nuclear battery is very proliferation resistant and if buried inside a ship it should be reasonably safe. Am I missing something here?

ref Links:

Leon Neihouse said...

The pebble bed reactor now being developed at MIT can be volume produced in manufacturing facilities such as shipyards and towed to any operating site accessible by water. Shipyard capacity now exists to provide 80% of our power from this single source by 2050.

Leon Neihouse

donb said...

Charles Barton wrote:
The current air (transport) industry is dependent on fossil fuel derivatives for power, and there is no easy substitutes for them. Biofuel advocates say that it will solve the problem, but I had and still have reasons for questioning this claim.... The energy economy of the bio fuel project is questionable.

I read recently (can't recall the source) that for current biofuels process lose 80% of the carbon inputs when producing the fuel. Using nuclear process heat, essentially all the carbon could be used for fuel. The amount of fuel produced would be five times greater than presently from the same amount of biomass. The majority of the energy in the fuel would be from nuclear reactions, so the energy return on investment for the biological process would be quite positive. There are other proposals to extract CO2 from the air to produce liquid hydrocarbon fuels using nuclear energy.

We probably don't need to stop man-made CO2 emissions totally. I remember reading years ago (again, I can't remember the source) that over geologic time scales (neglecting the effects of the industrial revolution), CO2 in the air has been decreasing such that life on land would cease to exist in perhaps 200,000 years. So modern man has come along in the nick of (geologic) time to save land-based life on earth. We have overshot the goal, but we also now have the ability to build the tools to strike the proper balance.

Anonymous said...

I would like to see Charles run a few calculations on the process of using C02 + H2 to make liquid hydrocarbon fuel for our jet transport and other machines where liquid fuels would be very hard to replace. Many seem to suggest solar in particular is able to provide the energy for this route, though it just seems an impossible task for such a low energy density power source. Nuclear is King. Alex

Charles Barton said...

i am of yet unconvinced by by the argument that a synthetic hydrocarbon produced from atmospheric CO2 by the Fisher - Tropsch process is going to solve the problem of powering transportation. My assessment is that electrification would return greater social benefits, especially in terms of health care cost savings. I do allow for a 2050 fossil fuels equal to 20% of current use, but there will be many demands for that allotment.

Alex P. said...

you are perfectly right about the usefulness of electrification of both transportation (trains, electric/plugin vehicles) and space heating (electric heat pumps) and instead the difficulty of producing liquid fuels from CO2 via FT processes

However, there are a lot of applications where the need of liquid fuels is absolutely mandatory (ships, airplanes, some industrial applications, etc..), so the case to produce some liquid "biofuels" from agriculture waste non-food crops, using heat and electricity from LFTRs. I think this is the easiest and quickest way, and in particular, the less energy intensive one, even if the energy come from LFTRs

Charles Barton said...

Long distance air travel is a special case, and would require a carbon based Liquid fuel. Industrial heat can be facilitated by non-stored H2. Burning H2 will give you all the heat you would want for high temperature industrial processes. Burning a carbon based liquid fuels in air produces nitrous oxide and particulates. Before we go down that road we ought to think about it.


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