Power generated by photovoltaic systems is clean, renewable and becoming more affordable. So why isn't it in more widespread use in Africa which is bathed in sunshine? Mike Crawley and Susanna Salafia report on what is going wrong.

In rural areas of Zimbabwe, there is plenty of sun but not much electricity. That is about to change. Zimbabwe is on a push to get solar energy systems into its villages.

At the forefront is a new project to supply 250 rural schools and 250 rural clinics throughout the country with photovoltaic systems, which produce electric current from solar energy, burning no fuel and causing no pollution. It is to be paid for by Italy's foreign affairs ministry at a cost of 16 billion lira.

Unfortunately, projects like this are few and far between. Despite solar power's potential to replace some of the traditional fossil fuel energy sources being blamed for global warming, and its ability to provide power in places that have little or no access to a national electricity grid, photovoltaic systems have not taken off on a large scale in Africa.

The World Bank and the UN Development Programme are certainly talking about promoting renewable energy sources. In recent annual reports, the World Bank has trumpeted what it calls its Photovoltaic Market Initiative for disseminating solar energy. The UNDP is also pushing solar energy through its World Solar Programme, which started in 1996 and encompasses more than 300 renewable energy projects in 73 countries.

But experts in the field say the development heavyweights are in reality doing little to encourage solar energy. "Most of the multilateral development banks are lending money for fossil fuels instead of renewables," says Corin Millais, solar campaign co-ordinator for Greenpeace in London.

The big funding bodies tend to invest in large-scale projects, while photovoltaic systems fit the needs of small-scale rural users, says Amal-Lee Amin, a doctoral researcher at the University of Sussex Science Policy Research Unit. "In no way could a person who wants a solar house system get a soft loan from the World Bank because it's just too small," Amin says.

She says rural people's limited access to credit is one of the key issues blocking more widespread use of photovoltaic systems.

As with all of its funding, World Bank loans for solar energy come with conditions that may not be easy to meet, ranging from long-term land leases to privatisation of national electricity systems.

The comfort of familiarity can also prompt funders to stick with the status quo and shiver at the risk of shifting to new technologies. But the international development funding bodies are not the only obstacles facing solar power.

There is strong political pressure on governments - both from users and suppliers - to subsidise traditional fuel sources such as kerosene, giving it a greater price advantage over solar energy.

Although major oil companies like Shell and BP talk of major increases in their renewable energy investments, Millais says their claims need to be measured in comparison to their massive emphasis on non-renewable sources.

Per capita consumption of electricity in the developing world more than doubled between 1980 and 1995. In Zimbabwe, per capita consumption of electricity is 925 kilowatt hours annually, compared with the average in the developed countries of more than 7,500 kilowatt hours.

The government has wanted for years to replace the use of candles and kerosene lamps in rural areas of the country with photovoltaic systems. In addition to the minimal environmental impact, it is easier to install the systems than bring electric current from urban areas.

The spots chosen for the Zimbabwean project have one of the world's highest annual amounts of solar radiation, says J.C. Battaglia, director of Agmin, the Italian procurement agency issuing the bid for installing the systems. He says the systems can operate for up to eight days without sun.

Some success with solar energy has been seen in India, which has an entire government ministry devoted to non-conventional energy sources. There is also the India Renewable Energy Development Agency, which channels World Bank loans to projects, and the government-funded Rural Electrification Corporation. In some parts of India, entrepreneurs are increasingly stepping in to meet the demand for small-scale solar power.

But in South Africa, photovoltaic use has declined in recent years, something that Battaglia says was brought about by central government policies that interfered with the operation of small-scale local suppliers.

The European Union has set a target of generating 12% of electrical power through renewable sources by 2010.

The United States and Japan are currently the world leaders in developing photovoltaic cells, while the European Union runs the Valoren project to test photovoltaic technology. All are looking for export markets, and are gradually turning more attention to the developing world.