The solar and wind innovations that got us where we are today — and those waiting in the wings — point to a hopeful future.

April 6, 2015 — Inside a sprawling single-story office building in Bedford, Mass., in a secret room known as the Growth Hall, the future of solar power is cooking at more than 2,500 °F. Behind closed doors and downturned blinds, custom-built ovens with ambitious names like “Fearless” and “Intrepid” are helping to perfect a new technique of making silicon wafers, the workhorse of today’s solar panels. If all goes well, the new method could cut the cost of solar power by more than 20 percent in the next few years.

“This humble wafer will allow solar to be as cheap as coal and will drastically change the way we consume energy,” says Frank van Mierlo, CEO of 1366 Technologies, the company behind the new method of wafer fabrication.

Secret rooms or not, these are exciting times in the world of renewable energy. Thanks to technological advances and a ramp-up in production over the decade, grid parity — the point at which sources of renewable energy such as solar and wind cost the same as electricity derived from burning fossil fuels — is quickly approaching. In some cases it has already been achieved, and additional innovations waiting in the wings hold huge promise for driving costs even lower, ushering in an entirely new era for renewables.