Imagine windows that not only provide a clear view and illuminate rooms, but also use sunlight to efficiently help power the building they are part of.

MIT engineers report a new approach to harnessing the sun's energy that could allow just that.

The work, to be reported in the July 11 issue of Science, involves the creation of a novel "solar concentrator.

Light is collected over a large area [like a window] and gathered, or concentrated, at the edges

As a result, rather than covering a roof with expensive solar cells (the semiconductor devices that transform sunlight into electricity), the cells only need to be around the edges of a flat glass panel

In addition, the focused light increases the electrical power obtained from each solar cell "by a factor of over 40

Because the system is simple to manufacture, the team believes that it could be implemented within three years—even added onto existing solar-panel systems to increase their efficiency by 50 percent for minimal additional cost.