It's cheap and clean but solar power generally needs the sun to shine. At night, a different power source is required — or expensive batteries. Now, Stanford University has developed solar panels with a thermoelectric generator that captures heat after the panels have been in the sun all day. Known as "radiative cooling", the process allows solar installations to keep providing some power at night. It could greatly reduce or even eliminate the need for batteries, which would be very useful in remote areas, where millions of people live without easy access to electricity.
A report in the journal Applied Physics Letters says the system could offer a "continuous renewable power source". The generator required is cheap and can be retrofitted to existing solar installations. And solar panels aren't the only things that produce radiative cooling, which comes from the temperature difference between a surface and the air around it. In theory, all sorts of things might one day generate electricity this way.