A concentrator solar cell produced by Boeing-Spectrolab has recently achieved a world-record conversion efficiency of 40.7%, establishing a new milestone in sunlight-to-electricity performance. The US Department of Energy’s National Renewable Energy Laboratory (NREL) verified the milestone.
This breakthrough may lead to systems with an installation cost of only $3 per watt, producing electricity at a cost of 8-10 cents per kilowatt/hour, making solar electricity a more cost-competitive and integral part of the US energy mix.
Attaining a 40% efficient concentrating solar cell means having another technology pathway for producing cost-effective solar electricity. Almost all of today’s solar cell modules do not concentrate sunlight but use only what the sun produces naturally, what researchers call “one sun insolation,” which achieves an efficiency of 12 to 18%. However, by using an optical concentrator, sunlight intensity can be increased, squeezing more electricity out of a single solar cell.
The 40.7% cell was developed using a multi-junction solar cell. This type of cell achieves a higher efficiency by capturing more of the solar spectrum. In a multi-junction cell, individual cells are made of layers, where each layer captures part of the sunlight passing through the cell. This allows the cell to get more energy from the sun’s light.
For the past two decades researchers have tried to break the “40-percent efficient” barrier on solar cell devices. In the early 1980s, DOE began researching multi-junction gallium arsenide-based solar cell devices, multi-layered solar cells which converted about 16% of the sun’s available energy into electricity. In 1994, DOE’s National Renewable Energy laboratory broke the 30% barrier, which attracted interest from the space industry. Most satellites today use these multi-junction cells.
Earlier in November, RoseStreet Labs, LLC and Sumitomo Chemical Co., Ltd. (Sumitomo) formed a joint venture, RSL Energy, Inc., for the development and manufacturing of full-spectrum solar cells. The joint venture will be headquartered in Phoenix, Arizona.
RSL Energy will commercialize next-generation technology utilizing full-spectrum solutions that targets practical efficiencies above 48% in both single junction and multi-junction devices. (Earlier post.)
(A hat-tip to Marty!)