07/05/2007 - 07:00

Keep all options on the table

Amory has the impression that I'm not a strong supporter of energy efficiency. In fact, as he
knows, I've worked on energy efficiency since 1969, well before the 1973 oil "crisis." My
colleagues and I developed what is now known as "life cycle analysis," beginning with the study
Margaret Fels and I did of the automobile as a manufactured article (See the December 1993 issue of
the
Bulletin of the Atomic Scientists; available as a PDF from berry@uchicago.edu.) We sought
to identify steps in processes that would be good targets for technological innovation.

This led to investigations of other areas by our group and others. We then moved into more basic
questions--whether and how one could use methods of thermodynamics and optimization to design more
efficient systems and processes. (See our book
Thermodynamic Optimization of Finite-Time Processes.) I applaud the work Amory does to
propagate the distribution and use of energy-efficient technologies and lifestyles. That subject is
in no way the basis of our differing viewpoints.

My point is that no single approach will accomplish the goals of
reducing the impact we have on the environment, improving the living standards of people
throughout the world, and providing the basis of a sustainable human society.

We certainly need to move to energy-efficient technologies, but we also need to provide energy
to people who don't have clean, reliable water supplies, adequate (or even any) electricity or
motor transportation. We need to recognize that India and China are on growth trajectories that
make our energy growth curve look flat. China is planning to build roughly one nuclear plant per
month, while building one coal-based generating station every
week! It's impossible for the efficient technologies that Amory correctly advocates to be
available on a timescale or size scale that could accomplish what the Chinese power plants will
provide.

Yes, China improved its energy efficiency, but this barely lowered the slope of its energy
demands. Efficiency can't bring the total electric power needs or overall energy needs of China or
India to a constant, level line in time.

Another point that we haven't really discussed: alternative sources of energy and carbon
sequestration. Some of these such as combustibles derived from cellulose will probably be
moderately important in our lifetimes. But the public discussion has carefully neglected "little"
problems--for instance, ethanol absorbs water too readily to be shipped by pipeline. So presumably
we would distribute it by trucks, using up the very fuel they carry! This problem has to be
included in the overall assessment of the effectiveness of ethanol as fuel.

As for carbon sequestration, underground storage chambers for carbon dioxide under high
pressures are known to explode. Hydrogen is popular in some circles, but we must recognize that it
is a form of energy storage, not an energy source on our oxygen-rich planet. If we can find ways to
generate hydrogen from energy sources that don't produce greenhouse gases, such as solar
photodriven electrolytic cells or electrolysis at very high temperatures, then perhaps we could
justify hydrogen as a fuel for some purposes.

The relative costs of coal and nuclear power have been studied in several recent, extensive
studies: "Nuclear Power Joint Fact-Finding June 2007" (The Keystone Report); "Projected Costs of
Generating Electricity, 2005 Update," International Energy Agency, OECD; "The Economic Future of
Nuclear Power," University of Chicago (2004); and "The Future of Nuclear Power," MIT (2003). The
Keystone Report indicates that the cost of constructing modern nuclear plants has been about
$2,000-$3,000 per kilowatt-hour (kWh) in countries where such plants have been built recently; the
projection of this study for the United States is $3,600-$4,000 per kWh.

The costs of supplying coal versus nuclear power depend sensitively on whether there is a carbon
tax; some models discussed in these studies indicate that the delivered cost per kWh of nuclear
power could easily be about the same as coal if there were some type of carbon tax. The relative
costs of coal and nuclear power are changing as technology and regulation evolve. A study by the
Secretary of Energy's Nuclear Energy Task Force [
"Moving
Forward with Nuclear Power: Issues and Key Factors" (PDF 388 KB)
] argues that some form of
financial aid and inducement will be needed to stimulate nuclear power in this country

We will need careful cost and cost-benefit analyses that account for externalities, examine
varieties of scenarios, and recognize the ranges of uncertainties in order to choose the proper
path. However, it would be a serious mistake to close off potentially important contributors to our
overall energy program. Therefore, abandoning nuclear power would be as foolish as halting efforts
toward energy efficiency.