Sustainable Energy


President-elect Barack Obama, July 17, 2008

"For decades, Al Gore has challenged the skeptics in Washington on climate change and awakened the conscience of a nation to the urgency of this threat. I strongly agree with Vice President Gore that we cannot drill our way to energy independence,
… but must fast-track investments in renewable sources of energy like solar power, wind power and advanced biofuels, and those are the investments I will make as President."

Like President Obama, I heartily agree with Vice President Gore that we must reduce carbon combustion to the maximum extent possible. But I do not believe that "solar power, wind power, and … biofuels" (advanced or otherwise) can possibly accomplish a significant reduction in carbon dioxide emissions. On the other hand, this essay advocates a known and effective alternative. Nuclear power is the least damaging, most compact way of generating energy, and there is a well known way to make it safe, renewable, and sustainable. It depends upon a resource base that was generated by stars inordinately larger than our little Sun, long before our aboriginal dust cloud condensed into our Solar System.

I doubt that we can do without cement based on calcium oxide, which is part of the silicate component of Portland cement. Calcium oxide is obtained from calcium carbonate (chalk or limestone) by driving off the carbon dioxide.

We probably cannot avoid using carbon to extract metals from their ores.
So we cannot entirely shut down the coal mines, but we should entirely replace the coal burning power stations. A typical coal burning power plant has a capacity of about a gigawatt, that's a thousand megawatts. It consumes millions of tons of carbon, and emits more than three times that mass of CO2, and also hundreds of tons of sulfur oxides and nitrogen oxides, which are acidic, toxic, and carcinogenic.
I doubt that solar, wind, or biofuels can replace many of those.
It is a matter of simple arithmetic — you have to appreciate the difference between tons and millions of tons, or between megawatts and gigawatts. It is also a matter of the difference between kilowatts and kilowatt-hours, which is the difference between power and energy. I do occasionally require several kilowatts of power for my home consumption, but my average rate of energy consumption is less than 24 kilowatt-hours a day. A photovoltaic rooftop that can deliver as much electric energy as I use in a day, will certainly not be able to meet my night-time power demand. Even if I store energy enough in a rechargeable battery, I will need enough more to deal with the fact that even a good battery returns about 75% of the energy needed to charge it.

I do not see how we can make N times more efficient use of biofuels than the eighteenth century did, N being the ratio of the world's present population to what it was then, times the additional demands per person that modern democratic, civilized life requires.
(Peasants, serfs, and slaves were also biofueled. Life was cheap.) "Carbon sequestration" wasn't mentioned above, but it's nonsense too.
There is evidence that wind and biofuels are of near zero or even negative value.

An honestly scientific or engineering statement of the capability of an electric power project would say what its actual (maximum) power capacity was, and its expected annual energy output; — in megawatts, and megawatt-hours. But far too many of the "eco-friendly" projects websites, if they give these figures, tart them up with a dubious claim as to the number of average homes they can supply. The trouble with the average consumption of a household is that when the commercials come on during a popular program, the people en masse get up and switch on coffee makers, or open the refrigerators. There is a sudden peak in demand. In Britain, it's electric kettles.

Your installed power generating capacity absolutely must respond to these sudden demands. That's the peak capacity requirement, and it's much higher than the average. Peak electric generation, spinning reserve on demand, is therefore of much higher value per kWh than the average.

The least valuable energy per kWh is the kind that, like the wind, is either there or not there, regardless of demand. Ask your favorite weatherman to predict what the windspeed will be, tomorrow, hour by hour, to the nearest five mph. Power varies as the cube of the windspeed, so the level of power output is hopelessly erratic, painfully so to any distribution agent trying to match output with demand. The British Met Office issues gale and storm warnings for fairly large regions of the surrounding seas, for perhaps a whole afternoon or evening, but they don't ever promise a steady 40 mph.

I fear that wind power is far less environmentally benign per megawatt-hour of reliable energy than hydroelectric dams. Wind power definitely kills bats and big birds, it breaks down in "strong gale force" winds, it costs a great deal of carbon dioxide emissions in the construction phase, As for the generators, the most advanced technology uses exceptionally superior permanent magnets, which require as much as two tons per turbine of the rare earth metal, neodymium, the mining of which in China is reported ( Daily MailPHS News Hour) to be disastrously polluting.

I predict that if ever sanity prevails and we replace all the methane and coal powered generation by nuclear, and replace all the gasoline with hydrogen or electricity from reactor-fueled generators, the environmentalists (of whom I am one) will launch a jihad to take down all the wind farms.

Solar power is abundant in the deserts, southern California, and the Australian Outback. But Paul McCready's wonderful solar powered light 'plane had to wait for sunny weather in France in order to fly the classic challenge of crossing the Channel to England. However, in the places where clear sunshine is fairly common, solar power generation has the virtue that it tends to coincide with one of the big demands, namely air conditioning.

I am convinced that the most sustainable, environmentally clean, inconspicuous energy technology is one that makes renewable use of a cosmic fossil fuel, as indeed geothermal power does on a small scale.

It is not wind, sun, water power, and biofuels. They were the basis of every empire almost right up to the founding of the USA in 1776. They were superseded by coal and hydrocarbons since the Industrial Revolution.

The technology of the immediate future is the renewable version of nuclear fission.
Some uranium (and other) isotopes are fissile, others are not. The USA presently receives almost a fifth of its electrical energy from the fissile part of about 25,000 tons of uranium oxide per year. The fissile portion of that is less than one percent. If the rest of the uranium could be made fissile, the resource is vastly more sustainable than the forests that supplied Britain before the Industrial Revolution, or the primeval forest of what is now the industrialized east coast of the USA.

But it is indeed possible now to build a reactor which creates as much fissile fuel as it consumes, or even slightly more. I submit that this makes it a renewable technology. Argonne National Laboratories, funded by the United States Government, created such a reactor more than twenty years ago. It was called the Integral Fast Reactor. It was designed to be able to consume all of its plutonium, without making bomb-grade plutonium available. It converts its spent fuel into short-lived fission products, and more fuel rods. It even makes the energy-expensive uranium "enrichment" process obsolete. In April 1986 it showed that it was immune to the loss of power or coolant problem that had previously crippled the reactor at Three Mile Island, and which later that very month caused the catastrophe at Chernobyl. The project was halted by the Clinton administration in 1994, which I contend was the worst blow to energy independence and clean electricity ever. It was a Fast Reactor, because it did not use a "moderator" to slow down the neutrons. It was an Integral reactor, because its fuel cycle was designed to need no external processing other than the first load of fuel. The reprocessing step was done within the reactor complex. This minimised shipments by road or rail of dangerous or terrorist- attracting substances.

In a nuclear reactor, neutrons from the fission of one nucleus will either split another fissile nucleus, be captured by a non-fissile nucleus, or escape into the shielding. About 0.7 percent of natural uranium is the fissile isotope 235U. Because the fuel rods are mostly the common isotope of uranium, 238U, which is not split by slow neutrons, some of it becomes 239U and almost immediately 239Np, which decays further into 239Pu, which is fairly long-lived and fissile. Uranium to neptunium to plutonium. A fast reactor is designed to make better use of the plutonium than currently commercial designs which slow down the neutrons by collisions with hydrogen atoms in water, or in the case of the obsolete Chernobyl design, carbon atoms in graphite.

It is possible to recycle the unspent uranium and plutonium back into fuel rods, even in a reactor of current design, but eventually the plutonium becomes too contaminated with its 240 isotope to work with thermal neutrons. Isotope 240Pu, by the way, is enough to make plutonium unsuitable for a bomb, and it is fiendishly difficult to separate from 239Pu.

But a fast reactor can work with fuel rods containing 240Pu, and all its neutron-capture descendants, like americium and curium. It simply bombards them into something fissile. There is a whole family of metallic elements beginning with actinium, which are called the actinides. It is the second family of "rare earths" in the Periodic Table. Their chemical similarities are such that it is fairly easy to extract all the actinides chemically from a spent fuel rod. This separates them from the fission products, which are far more radioactive, but far smaller in total amount. It is much easier than any of the processes for making "enriched uranium" from natural uranium. It's chemistry, not nuclear physics. So it costs far less energy.

There is also a technology called a Liquid Fluoride Thorium Reactor, LFTR, which can produce comparable amounts of energy, by nuclear fission, from the element thorium. It is a breeder reactor that uses thermal neutrons. Thorium's only natural isotope 232Th produces 233U after capturing a neutron. Excellent research under the AEC showed that this can be done with the fluorides of 233U and 232Th dissolved in liquid lithium and beryllium fluoride, the neutrons being moderated by graphite. Such a reactor has several attractive qualities, including passive shutdown rather than catastrophic meltdown, but it seems to have been abandoned by the AEC because it did not produce bomb grade material.

Firewood and peat are biofuels, and the forests of England and of eastern North America are gone. They were renewable, but not renewed. The production did not meet the demand. The great forests of Finland survive, because the population is still small.

Horses, oxen, elephants, camels, peasants and slaves are also biofuelled, but they do not characterize a modern lifestyle.
The provision of light by candles of beeswax involves prodigious amounts of bio-energy.
Lamps fuelled by whale oil would not be popular with modern decent folk either.

You grow grain and feed it to the horses, then if you're a gentleman, a caballero, you ride the horse. It is true that there exists biofuelled transportation that is many times more efficient than horseback. It is called a bicycle, and in my own experience is as effective a way of commuting distances up to seven miles as a motor car, for a moderately fit person. The Japanese even used it for their surprise attack on Singapore.

But it is a dangerous way to commute on roads that are infested with automobiles. Discontinuous bicycle lanes that do not physically exclude the automobile are pure nonsense.

Can any biofuel advocate tell us by how much the productivity of an unsubsidized, naturally fertilized cornfield or sugarcane plantation fed to an ethanol production factory for tractors and automobiles can exceed the capabilities of the horses and oxen that would be supported by it in the olden days?
Then again, how or where are you going to find or biosynthesize plants that use photosynthesis more efficiently, even from our point of view, than the aboriginal vegetation?

The Titan Wind Project press release says that:

"The world's largest wind farm, the Titan Wind Project, will be built in South Dakota - the 2,000 turbine, 5,050 MW wind farm will provide enough energy to power 1.5 million homes--more than five times the amount needed to power every home in South Dakota."

This is false. The turbines do not produce anywhere near their peak power in anything less than a near gale, Beaufort Force 7, about 34 mph. A mere strong breeze of 27 mph will drop the output from 5050 MW to a mere 3681 MW. The usual capacity factor is lucky to be 25%. So it's more like an average output of 1261 MW, which is 1,261,000 kilowatts. Now, the average of 1,261,000 kilowatts for a million and a half homes says that an average of 0.841 kW suffices for each home. That seems optimistic, when electricians tend to install a couple of 40 amp circuits for stove and all-house air conditioning, and at least another six at 20 amps. Forty amps at 110 volts is already 4.4 kilowatts, and people in the same region tend to use their cooking stoves or their A/C at the same time.