Illustration Photo: Long Island Solar Farm in USA (credits: Brookhaven National Laboratory / Flickr Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0))

Illustration Photo: Long Island Solar Farm in USA (credits: Brookhaven National Laboratory / Flickr Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0))

Illustration Photo: Nam Theun 2 Hydroelectric Power Plant in Laos (credits: Asian Development Bank / Flickr Creative Commons Attribution-NonCommercial 2.0 Generic (CC BY-NC 2.0))

Illustration Photo: Nam Theun 2 Hydroelectric Power Plant in Laos (credits: Asian Development Bank / Flickr Creative Commons Attribution-NonCommercial 2.0 Generic (CC BY-NC 2.0))

Photo: Researchers at Purdue University created this 2-inch silicon wafer coated with thin films of tantalum and silicon nitride for enhanced solar absorption. The solar absorber was designed for use in “concentrated solar power” plants that might run up to 24 hours a day. (Purdue University image/Zhiguang Zhou)