Microbial fuel cells (MFCs) that make use of the energy given off by soil microbes are amongst the technologies that hold promise for bringing power to developing states, where electricity is often scarce.

The cells also form part of a project that has just won a grant of almost 200,000 dollars in the 'Development Marketplace' competition, for which results were announced at 'Lighting Africa 2008' this May 5-8 conference took place in the Ghanaian capital of Accra. The project, developed by six students at Harvard University in the United States, was one of 16 winners selected from 52 finalists competing to bring innovative lighting products to the 74 percent of Africans without access to electricity.

The Development Marketplace competition was held under the 'Lighting Africa' campaign, launched towards the end of last year by the World Bank Group. Lighting Africa aims to provide 250 million people on the continent with safe, reliable and economical lighting products and energy services that do not make use of fossil fuels, by 2030.

The Harvard students, four of whom come from Africa, have created Lebônê Solutions to deliver low-cost energy using microbial fuel cells. Their grant will be matched by private industry.

South African Hugo Van Vuuren, founder and managing partner of Lebônê, says the cells are very simple to make and can be built locally.

We're all still very excited. This is a potentially big innovation and I have to credit the IFC for backing innovative ideas rather than just pushing the current technology. We can't wait to get started and see if we can bring this technology to Africa. (The IFC, the International Finance Corporation, helps build the private sector in developing nations; it forms part of the World Bank Group.)

A microbial fuel cell taps into the energy that soil microbes generate when they break down organic matter. Literally, this is energy from dirt: no special microbes or conditions are needed other than enough moisture for the bugs to do their work.

Essentially all you do is dig a hole, layer an anode, some soil, sand and a cathode -- and connect the anode and cathode to a circuit board to charge a battery that can power an LED (light emitting diode) light, run a radio or charge a mobile phone.

Harvard biology professor Peter Girguis developed the technology, called Living Power Systems, and is their technology partner.