Renewable options 4: solar power
Markets surge for sun's energy

Although still tiny by energy industry standards, the world market for solar cells nearly tripled from annual sales of about 70 megawatts in 1994 to more than 200 megawatts in 1999. About half the market is for remote non-residential uses such as highway signals, radios, water pumps and purification systems, where the most common alternative is a high-cost diesel generator. Another 20 per cent goes to small consumer products such as calculators and watches. Unlike most energy technologies, solar cells can be used economically in such small devices.

Individual residential solar systems account for the remaining 30 per cent. Solar cells have long been the most economical power source in remote parts of the developing world. Thousands of rural families in countries such as the Dominican Republic, Brazil, Indonesia, India, Morocco, and Kenya now have solar power. The systems are typically tiny - less than a square metre in size with a generating capacity of 20-100 watts - but life transforming. The clean light allows children to read at night, without the health hazards of kerosene fumes.

The isolated, mountainous areas that electricity lines do not reach are usually the places that phone lines shun as well. Thus, in much of the developing world there is the potential for the revolutions in energy and telecommunications to meet up. In the next decade, a new space race fuelled by 1,700 communications satellites, 10 times the number now in orbit, is set to transform the global telecommunications network. These satellites will be able to bring phone service and internet hook-ups to remote homes powered by PVs.

The 1990s also saw thousands of solar panels hoisted atop homes and office buildings in industrial country cities such as Tokyo, Berlin and Zurich - places that are already well served by an electrical grid.

Solar-panelled housing, Tokyo, Japan
© J. Holmes/Panos Pictures

In 1990, grid-connected homes and buildings accounted for just 2 per cent of the market for PVs. By 1996 their market share grew to 8 per cent, but in 1997 it jumped to 21 per cent. In the United States, it now costs home buyers roughly $20,000 extra to buy a solar powered home, an option that would add some $100 a month to a typical mortgage. The actor Robin Williams has one, but he paid much more, since his home is not a modest one.

Government support is triggering the current boom. Japan has been the leader in recent years, providing generous subsidies to roof top solar systems. Between 1994 and 1998, some 12,000 customers took advantage of the government's cash subsidy for PVs, bringing the total of solar-powered homes in Japan to 25,000, generating 48 megawatts of solar power.

Spurred by the Japanese example and strong public support, both the United States and the European Union announced Million Solar Roofs programmes in 1997. These programmes, which are still being formulated, are partnerships with state and local governments as well as the private sector and are intended to provide tax incentives, low cost financing and other assistance to those who want to use solar power.

In individual European countries, Germany, Switzerland, Norway and the Netherlands all have long standing solar incentives in place, and Italy has recently joined the club. Germany plans to launch the largest effort to date: a five year programme to build 100,000 rooftop systems. Already, the country hosts a number of high-profile solar installations, including a 1 megawatt rooftop power plant, the world's largest, which sits atop the halls of the new Munich Trade Fair Centre.

Solar-powered buildings are becoming easier to build, as PVs are now directly integrated into roofing shingles, tiles, and even window glass - turning ordinary construction materials into nearly invisible power generators. For example, Kawneer, an aluminium building material manufacturer, and Solarex, a maker of PV modules, teamed up to produce the 'PowerWall', which can be used instead of tinted glass or aluminium on building facades as a sun shade that also generates power. And a new pre-designed 'zero-energy house' from Misawa, Japan's largest homebuilder, is fully powered by a solar array that doubles as a roof.

Technological advances have driven down solar cell costs by 80 per cent since 1980, and further declines are expected, which may make solar electricity a potential competitor to fossil fuels. But in areas served by electric lines, solar power still costs 2-5 times that from the grid. Automated manufacturing, larger factories, and more efficient cells are expected to reduce costs in the near future.

Among the large new manufacturing plants announced recently are a 20-megawatt factory that BP Solar are building in Australia and a 25-megawatt plant by Pilkington Solar in Germany. And compared to conventional solar cells, the new 'thin film' cells use less raw material, which makes them cheaper. Moreover, they do not need to be sliced or rigidly encased and can be made into large, flexible sheets ideal for incorporating into building materials.

The latest surge in the PV markets suggest that solar power will play an important role in building a 21st century energy system that serves more people while polluting less. Solar panels are not only bringing light to some of the most inaccessible parts of the world but can also provide clean power in burgeoning cities.

Molly O'Meara is a Research Associate at the World Watch Institute

Sacramento's sun In the United States, solar power has received a boost from a locally-owned electric utility in California. The Sacramento Municipal Utility District (SMUD) launched its PV Pioneers Program in 1993. Each year, the utility buys about 100 solar systems and installs them on area homes, where they feed power into the electrical grid. The utility retains ownership of the solar panels. And homeowners pay an extra $4 each month for the privilege of hosting this clean energy source. Already, the utility has installed 5.7 megawatts' worth of grid-linked solar panels on more than 420 homes and buildings, and above several parking lots. Another 10 megawatts are scheduled between 1998 and 2002. To meet this goal, SMUD initiated the second phase of its solar program, PV Pioneers II, in 1998. Now SMUD sells grid-connected PV systems to interested homeowners, and buys back the electricity produced by their roofs. 'Net metering' makes this transaction possible: the rooftop's output is subtracted from the customer's use of power, so at the end of the month, the customer pays a utility bill that covers the 'net' electricity used. The systems supply 20-80 per cent of a household's power, so customers can expect much lower bills. To help sustain the program, SMUD has signed a long-term contract with a solar manufacturing company to begin producing cells locally. Molly O'Meara

For more details of how you can help, click here.