The total solar eclipse in the United States on 21 August will allow millions of people to participate in planetary science (see Nature 545, 386; 2017). They can reflect, too, on solar energy, energy conservation and the reliability of electrical systems based on alternative energy.

Commercial solar-power production during the partial eclipse in California, for example, will drop from around 9 to 3 gigawatts between 9:00 and 10:30 local time, rising back to about 9 GW by noon. The California Independent System Operator is procuring extra resources to compensate.

Alternatively, those enjoying the eclipse could simply cut their electricity usage for the duration. The president of the California Public Utilities Commission, Michael Picker, suggests that such a community effort would send a message to the US Department of Energy in response to Secretary Rick Perry's request for a review of the possible negative effects of alternative energy on the electrical distribution system.