EPIBuilding a Sustainable Future
Lester R. Brown

Chapter 9. Cutting Carbon Emissions in Half: Converting Sunlight into Electricity

When a team of three scientists at Bell Labs discovered in 1952 that sunlight striking a silicon surface could generate electricity, they gave the world access to a vast new source of energy. No country uses as much energy as is contained in the sunlight that strikes its buildings each day, writes Denis Hayes, former Director of the U.S. government's Solar Energy Research Institute.26

Solar cells were initially used to provide electricity in remote sites in industrial countries, such as in national forests or parks, offshore lighthouses, and summer homes in remote locations. In recent years, a vast new market has opened up in developing-country villages that are not yet linked to an electrical grid. In many such situations, the cost of building a centralized power plant and a grid to deliver relatively small amounts of electricity is prohibitive, which helps explain why 1.7 billion people in developing countries still do not have electricity. As the cost of solar cells has declined, however, it is now often cheaper to provide electricity from solar cell installations than from a centralized source.27

In Andean villages, solar installations are replacing candles as a source of lighting. For villagers who are paying for the installation over 30 months, the monthly payment is roughly the same as the cost of a month's supply of candles. Once the solar cells are paid for, the villagers then have an essentially free source of powerone that can supply electricity for decades. In villages in India, where light now comes from kerosene lamps, kerosene may cost more than solar cells.28

At the end of 2002, more than 1 million homes in villages in the developing world were getting their electricity from solar cells. If families average six members, then 6 million people are getting their residential electricity from solar cells. But this is less than 1 percent of the 1.7 billion who do not yet have electricity. The principal obstacle to the spread of solar cell installations is not the cost per se, but the lack of small-scale credit programs to finance them. As this credit shortfall is overcome, village purchases of solar cells could climb far above the rate of recent years.29

The residential use of solar cells is also expanding in some industrial countries. In Japan, where companies have commercialized a solar roofing material, some 70,000 homes now have solar installations. Consumers in Germany receive low-interest loans and a favorable guaranteed price when feeding excess electricity into the grid. In industrial countries, most installations are designed to reduce the consumer's dependence on grid-supplied electricity, much of it from coal-fired power plants.30

The governments with the strongest incentives for the use of solar cells are also those with the largest solar cell manufacturing industries. In Japan, for example, residential installations totaled roughly 100 megawatts in 2001. The comparable figure for Germany was 75 megawatts. The United States, a far larger country, was third—with 32 megawatts of installations. India was fourth with 18 megawatts. Japan leads the world in solar cell manufacturing, with some 43 percent of the market. The European Union, led by Germany's vigorous program, has moved into second place with 25 percent of output. The United States, with 24 percent, is now third.31

The cost of solar cells has been dropping for several decades, but the falling cost curve lags wind by several years, making solar-generated electricity much more costly than power from wind or coal-fired power plants. Industry experts estimate that with each doubling of cumulative production, the price drops roughly 20 percent.32

Over the last seven years, solar cell sales have expanded an average of 31 percent annually, doubling every 2.6 years. (See Table 9-2.) Since there is little doubt that solar cells will one day be an inexpensive source of electricity as the scale of manufacturing expands, the challenge for governments is to leapfrog into the future by accelerating growth of the industry. Only very modest government incentives are needed to do that. If we can quickly reduce the cost of solar cells, they will join wind as a major player in the world energy economy.33


Table 9-2. Trends in Energy Use by Source, 1995-2002
Energy Source
Annual Rate of Growth
Solar Photovoltaics
Wind Power
Geothermal Power1
Natural Gas
Nuclear Power
1Data available through 2000. 2Data available through 2001.
Sources: See endnote 33.


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26. Denis Hayes, "Sunpower," in Energy Foundation, 2001 Annual Report (San Francisco: February 2002), pp. 10-18.

27. Population without electricity in World Summit on Sustainable Development, Department of Public Information, Press Conference on Global Sustainable Energy Network (Johannesburg: 1 September 2002).

28. "Power to the Poor," The Economist, 10 February 2001, pp. 21-23.

29. Bernie Fischlowitz-Roberts, "Sales of Solar Cells Take Off," Eco-Economy Update (Washington, DC: Earth Policy Institute, 11 June 2002).

30. European Photovoltaic Industry Association and Greenpeace, Solar Generation (Brussels: September 2001).

31. Fischlowitz-Roberts, op. cit. note 29.

32. Robert H. Williams, "Facilitating Widespread Deployment of Wind and Photovoltaic Technologies," in Energy Foundation, op. cit. note 26, pp. 19-30.

33. Paul Maycock, "Annual Survey of PV," Photovoltaic News, March 2003, p. 1. Table 9-2 from the following: wind power from Worldwatch Institute, Signposts 2002, CD-rom (Washington, DC: 2002), updated with AWEA, op. cit. note 13; solar photovoltaics from Maycock, op. cit. this note; geothermal power from Worldwatch Institute, op. cit. this note; oil from DOE, EIA, "World Oil Demand," International Petroleum Monthly, April 2003; natural gas and coal from Janet L. Sawin, "Fossil Fuel Use Up," in Worldwatch Institute, op. cit. note 13, pp. 34-35; nuclear power from Nicholas Lenssen, "Nuclear Power Rises," in ibid, pp. 36-37; hydroelectric power from BP, Statistical Review of World Energy 2002 (London: Group Media & Publishing, June 2002), p. 36.


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