You can now buy panels that plug into electrical outlets, but there are some important safety issues to consider when picking and installing a system.

© Patrick Junker for The New York Times

You can now buy panels that plug into electrical outlets, but there are some important safety issues to consider when picking and installing a system.

Ten U.S. states have legalized systems that can be plugged into standard wall outlets. The technology typically does not require permits or electricians.

© Poppy Lynch for The New York Times

Ten U.S. states have legalized systems that can be plugged into standard wall outlets. The technology typically does not require permits or electricians.

Researchers at Caltech and Sophia Space, a start-up, have developed a technology using solar power to prevent computer equipment from overheating in orbit.