energy frontiers

Energy frontiers

The world has more than seven billion people and is headed toward nine billion by the middle of the century. Demand for energy is rising relentlessly, but the fossil fuels that meet most of that demand are finite resources. The prospect arises of demand outstripping supply for oil, then for natural gas, and eventually for coal. New energy sources are needed, as well as better uses of the energy sources we already have. The possibility of climate change also motivates the search for new energy, but the threat of running short of conventional energy is the more immediate danger, by far.

So it is worth looking at energy frontiers, and doing so without the advocacy that often clouds the issue. Politicians and activists have turned the search for new energy sources into a dogmatic insistence on wind energy, solar energy and ethanol. Such attitudes contribute little to progress. Such attitudes in fact slow progress by diverting money from research into pork barrel projects and political pacification programs, which is what wind farms and solar farms and ethanol are today. It is not that wind, solar and ethanol cannot become valuable energy sources. Maybe they will, someday. It is just that they are not there yet, and the heavily subsidized and mandate-driven wind farms, solar farms, and ethanol production are not getting us any closer to a needed breakthrough. They contribute nothing to breakthroughs.

I once asked a wise older head at an energy company about hydrogen as an energy source, and he offered a very down-to-earth cautionary point. He said engineers back in the 1950s thought hydrogen might be the fuel of the future. In the ’60s and ’70s hydrogen still looked like the fuel of the future. In the ’80s and ’90s it still looked like the fuel of the future. (I spoke to him in the ’90s.) At some point, he said, you have to start asking whether maybe there are inherent limitations in an energy source that, decade after decade, looks like the fuel of the future rather than the present. Well, that same cautionary note needs to be included in discussions of other energy sources.

The energy frontiers include hydrogen, wind, solar, batteries, nuclear, wave, current, geothermal, water thermal and various forms of biomass (of which corn-based ethanol is only one form, and not a promising one).

Biomass and nuclear strike me as the two energy sources with the greatest potential. And when I mention nuclear, you will soon see that I also am referring, yes, to hydrogen, that fuel of the ever-receding future.

Biomass has the great advantage of being renewable. Grow the crop, feed it into some sort of distillery-type facility, and burn the resulting alcohol fuel. The carbon added to the air will eventually be absorbed out of the air by more growing crops. The problem has been to find a good crop. It needs three characteristics: it should grow prolifically, grow on marginal soils not needed for food crops, and break down easily in a reactor to form an alcohol fuel. Cornstarch is common and is easy to chemically break down into alcohol fuel, but corn is needed as food for both people and animals. Switchgrass is often mentioned as a candidate for cellulosic alcohol fuels, but apparently it cannot be easily broken down into an alcohol. I say “apparently” because I have not kept up on the research, but I vaguely recall that being mentioned as one of the reasons why we see no commercial growing of switchgrass for fuel yet.

What if we were to genetically engineer switchgrass or some other fuel crops? The engineering would need to make the candidate crops cold-tolerant, heat-tolerant and drought-tolerant, so that they could be planted in areas not already occupied by food crops. They would not need all of those qualities in one crop, of course. Different candidates could have different engineered tolerances for various circumstances. Some of those tolerances might best be acquired from other plants. For example, genes allowing for heat tolerance might be extracted from naturally heat-tolerant plants and inserted into a fuel crop.

The fuel crops also would be best if they could grow in poor soils, the biggest challenge. A plant cannot easily be engineered to thrive in nutrient-poor soil. Sandy soil, for example, tends to be composed of grains of quartz or some other tough mineral that does not provide nutrients, and rainwater seeps between the sand grains and washes nutrients away. But with enough creativity, plants might be engineered to reduce their nutrient demands just enough to cope with many poor soils. Think of it this way: no one is going to grow prolific crops in the Sahara Desert, but that does not mean no one can engineer crops for growth just south of the Sahara, in the dry Sahel region. Millions of rural poor people across Africa in the Sahel would love to have a new cash crop that might lift them out of poverty.

Genetic engineering also might increase the presence of soil nutrients while reducing the need of nutrients. Plants that are not fuel plants might be engineered to proliferate in a dry zone, to enrich the soil when they die and decompose.

Finally, the fuel crops need to be engineered so that they more readily break down in a reactor to become an alcohol fuel. It might be that microbes can be engineered to do the work for us. Here is an excerpt from a U.S. Energy Department announcement from Dec. 22, 2011:

“Washington D.C.—Researchers at the U.S. Department of Energy’s Joint BioEnergy Institute announced today a major breakthrough in engineering systems of RNA molecules through computer-assisted design. Scientists will use these new ‘RNA machines’ to adjust genetic expression in the cells of microorganisms. This will enable scientists to develop new strains of Escherichia coli (E. coli) that are better able to digest switchgrass biomass and convert released sugars to form three types of transportation fuels—gasoline, diesel and jet fuels.”

That’s just a step. Drain out the promotional “major breakthrough” phrasing and revise some of the other elements in order to imagine the possibilities: not just E. coli but other microbes, not just switchgrass but other crops, and not just the three named fuels but all hydrocarbon fuels and hydrocarbon chemical feedstocks.

Nuclear energy is useful for generating electricity and may become more useful. Nuclear power stations near seacoasts—preferably not quite as near or as vulnerable as the Fukushima Daiichi station—can use water for cooling. While we are at it, we can use electricity from nuclear power facilities near seacoasts to desalinate water for drinking and irrigation. And then take an additional step. Use those power facilities for electrolysis to separate seawater molecules into oxygen and hydrogen so that the hydrogen can be used as a gaseous fuel in factories, offices, stores, homes, cars and trucks.

Some people might object that it would be more efficient to build vehicles that run on electricity, as some vehicles already do today. But they do not do it well. Battery technology is more than 200 years old, and mature technologies are not easily revolutionized. We can still hope to see breakthroughs in battery technology, but while hoping, we can also diversify our investments in our energy future. Hydrogen from water is one of those possible diversifications. Drinking water from those same power plants, after desalination, would be a simultaneous benefit. Hydrogen also is important for chemical factories, and right now those chemical factories depend on hydrogen stripped from methane, one of those nonrenewable fossil fuels.

Nuclear power plants using thorium rather than uranium are a possible frontier. Thorium (Th-232) is three times more abundant than uranium in the crust of the Earth. Thorium will not produce a sustained nuclear chain reaction on its own, but Uranium 233 can be used to enrich thorium with neutrons, making the thorium more radioactive by converting some of the Th-232 into U-233. That has been tested and proven, but not commercially. A reactor using Th-232 and U-233 together can breed surplus U-233, which could free the system from relying on U-233 from other sources. The “breeder” reactor idea has been around for many decades, but technical challenges, costs and politics all have weighed heavily on the research and development. Currently, India is the nation with the strongest development program for thorium reactors, partly because of the nation’s large domestic supplies of thorium and partly because of the energy needs of a billion citizens.

November 2012