If you've ever seen a picture of the earth at night, you'll know why Africa is called the dark continent. The power grids of most African nations do not extend much beyond the major cities. When it gets dark, you have to either go to bed, or rely on batteries or the smoky and hazardous flickering of a kerosene lamp.

In total, 2 billion people around the world live without access to electricity and all the benefits that it brings. Even if the funds were available to connect them, the environmental impact of 2 billion extra users would be unacceptable. Is it possible to give people power without costing the earth? SolarAid is a brand new charity created with that precise purpose. Launching tonight at City Hall in London, SolarAid aims to enable the world's poorest people to access the benefits of clean, renewable electricity.

The charity's first project involves light. Kerosene lamps are common in Africa, but are expensive and polluting. Research also shows that people were spending up to 20% of their income on fuel for their lamps, and batteries for their radios and mobile phones. In a subsistence economy, expenditures like these are very costly. SolarAid's solution is to train local entrepreneurs to work with solar technology, turning kerosene lamps into solar lanterns. With a six-inch square of solar glass, three small LEDs, two rechargeable batteries and a little training, you can create a safe and sustainable source of light. Communities are immediately better off - firstly because there is a profit to be made as small micro-solar businesses are created and start selling lamps, and secondly as customers start using the lamps, making the most of free energy and gaining back 20% of their income.

Once people have light, other things follow. Most importantly, they can read. This gives children a chance to do homework, and parents an opportunity to educate themselves and learn new skills. Higher education goes hand in hand with lower birth rates, playing into Africa's population boom. The same simple solar panel that charges the lamps can also power a radio by day - another source of education, and also of news, informing people and drawing the poor into the political process. As SolarAid chairman Jeremy Leggett said tonight "this project impacts every one of the Millennium Goals, either directly or indirectly."

Mayor of London Ken Livingstone also spoke at tonight's launch, reminding the city crowd that "everybody hasn't contributed equally to the mess that we're in", and that keeping the developing world in poverty to maintain ecologically wasteful lifestyles is not an option. He praised SolarAid's innovation in empowering those who would not normally have access to solar technology. "A third of the world has no access to electricity" he said, "and leapfrogging them right through the stages of industrialisation to solar power is absolutely the right thing to do."

For more on SolarAid visit the website or watch the video below. I'll be interviewing SolarAid's director Nick Sireau next week, so if you've got a specific question, leave a comment and I'll try and ask it for you.