Photos: World's most efficient solar dish?

"This is actually the most efficient solar collector in existence," said Doug Wood, an inventor based in Washington state who patented key parts of the dish's design.

Wood signed the patent rights over to the student team, an independent project started in January that he credits with making his design practical and competitive: "They really have simplified this and made it user-friendly, so anybody can build it."

A key to inexpensive solar-dish design, according to Wood: smaller is better. A smaller dish requires so much less support structure that it ends up costing only a third as much for a given collecting area, MIT said in a statement.

Here, Wood demonstrates the solar dish's power by using it to set fire to a board held at the focal point. Earlier in the week, Ahrens demonstrated the same power on a field at the edge of the MIT campus. Almost instantly after he eased a plank of wood in front of the dish, MIT said, a big puff of smoke and flames erupted.