California became the first state in the nation to require homes built in 2020 and later be solar powered, following a vote by the Building Standards Commission.

The unanimous action on Wednesday finalizes a previous vote by the Energy Commission and fulfills a decade-old goal to make the state reliant on cleaner energy.

“These provisions really are historic and will be a beacon of light for the rest of the country,” said Kent Sasaki, a structural engineer and one of six building standards commissioners. “(It’s) the beginning of substantial improvement in how we produce energy and reduce the consumption of fossil fuels.”

While nobody spoke Wednesday in opposition, the commission received about 300 letters opposing the mandate because of the added cost, the Orange County Register reported.

One commission member worried the mandate would make it harder for California wildfire victims to rebuild. But supporters assured him that won’t be a problem, according to the newspaper.

Homeowners will have two options that eliminate upfront costs of adding solar: leasing the solar panels or signing a power purchase agreement that pays for the electricity without buying the panels, said Drew Bohan, executive director of the energy commission.

Read more: California becomes first state to mandate solar power for new home