Massachusetts Institute of Technology, 2007 - $20,000

This E-Team is developing an inexpensive solar generator for powering off-grid communities in the developing world. Unlike standard photovoltaic panels, which only produce electricity, the team's device meets the entire range of commercial and residential energy needs: heating, cooling, and electricity. Using common, inexpensive auto parts and plumbing supplies, the generator works by using sun-tracking parabolic mirrors to focus the sun's rays on a pipe containing liquid anti-freeze. The refrigerant is heated and vaporized through a heat exchanger, driving a turbine-alternator assembly to generate electricity. Wasted heat is captured by a condenser and used to heat water. Altogether, the system costs about $3,000 and produces enough energy to power an off-grid school, health clinic or community center in the developing world.

Update

The team is continuing to pursue the scaling and commercialization of this technology. There are two seprate ongoing efforts: a for-profit venture named Promethean Power (focus in India), and a non-profit named STG International (focus in Southern Africa).

• BBC video coverage of Promethean Power