Work is starting in Wyoming coal country on a new type of reactor. Its main backer, Bill Gates, says he’s in it for the emissions-free electricity.

© Benjamin Rasmussen for The New York Times

The damage was unusual, experts say, because turbines are built to withstand extreme weather. Iowa is a wind powerhouse, with thousands of turbines.

© Charlie Neibergall/Associated Press

The Federal Energy Regulatory Commission approved the biggest changes in more than a decade to the way U.S. power lines are planned and funded.

© Renaud Philippe for The New York Times

Electrical utilities said they weathered earlier conditions as persistent geomagnetic storms were expected to cause another light show in evening skies.

© NASA/Solar Dynamics Observatory

Officials warned of potential blackouts or interference with navigation and communication systems this weekend, as well as auroras as far south as Southern California or Texas.

© NASA/SDO