SOLAR TODAY - April 2010

| sustainable future advances

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Charting The Energy Road Ahead By J. Douglas BalcoMB, Ph.D

J. Douglas Balcomb retired as a research fellow from the National Renewable Energy Laboratory in 2003. He is the recipient of the Ericsson Award, the Department of Energy’s highest honor for contributions to renewable energy. He earned a Ph.D. in nuclear engineering from MIT in 1961 and has served as chairman of the American Solar Energy Society Board. He was instrumental in the quantification of passive solar performance, both by analysis and testing.

The opinions expressed here are solely those of the author.

Many believe the future of humanity looks grim if we stay on our present course. I concur. Consider cli- mate change, rising pollution, depletion of ocean fish stocks, a population grown beyond the Earth’s carrying capacity and nonrenewable resource depletion. I’ve just turned 75 and have had the good fortune to live during times when things were mostly good. Now I worry that my children and grandchildren face an uncertain future.

Far-sighted people have proposed plans for a sustainable future. Here’s mine. I call it The Energy Road Ahead. It’s simple enough to be expressed using just one graph, with one page of explanation.

The graph shows a 50-year transition from our present fossil-based energy economy to a sustainable renewable-based economy. The units used are quads (1015 British thermal units, or Btu) of primary energy. The 2060 end point is based on my intuition of what a good energy mix would be. The graph would seem to describe a major contraction in our standard of living, but this is definitely not the case. Why not? During the transition, end-use efficiency doubles while energy use is halved, resulting in

energy productivity remaining constant. Analysis done at the Rocky Mountain Institute ( rmi.org) shows that we nearly doubled our energy efficiency from 1979 to 1999. RMI believes an additional factor of two is easily within reach, in most cases at reduced cost. Energy use is not a measure of our economic status, but rather what the energy expended is doing for us. For instance, we don’t measure a vehicle’s utility by the fuel it burns, but by the cargo- or passenger-miles it covers per gallon of fuel. Energy cost might actually decrease when measured in units of energy productivity. The result in 2060 will be a society that is sustainable and productive.

Why just look at energy? Because wanton energy use, particularly coal and oil, is at the heart of most of the problems we face. Curtail fossil energy use while switching to renewable energy use, and we then have a chance of getting a grip on the other problems. Why does the graph deal only with the United States? Because we are the biggest problem, we can only solve our own problems, and hopefully, if we set an example, the rest will follow. Throwaway will be replaced by recycling. Materialism will be replaced

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(Based on the U.S. Energy Information Administration’s
factor of 9,884 Btu per kilowatt-hour to convert
from primary energy to electricity)

Balcomb Projects: Installations Required by 2060

Wind: To generate 12. 6 quads (1.274 x 1012 k Wh) would require 121,000 wind turbines, assuming 3-megawatt (MW) units operating at a capacity factor of 40 percent. This is only 14 times the total capacity installed in the United States at the end of 2008.

Solar Thermal: To generate 11. 9 quads (1.204 x 1012 k Wh) would require 1,600 solar farms, assuming 200 MW each, operating at a capacity factor of 43 percent. These would take up about 1,600,000 acres of land, which is about 5 percent of the suitable land area in the seven Southwestern states.

Solar PV: To generate 5. 9 quads (0.597 x 1012 k Wh) would require 63 million 3-k W systems plus 7. 6 million 25-k W systems, assuming a capacity factor of 18 percent. This would cover most of the rooftops in the United States.