Solar energy isn’t just for people who bolt a bunch of panels onto their roofs: The U.S. Energy Information Administration (EIA) says in its latest report that solar power is the fastest-growing source of renewable energy in the United States, and it’s expected to keep growing.

The administration said in October’s short-term energy outlook that the generating capacity of utility-scale solar, rose from 10 gigawatts (GW) in 2014, to 27 GW in 2017. That’s an annual growth rate of 39 percent, which is helping solar catch up to other renewable energy sources.

Yet the EIA is careful to note that this growth rate is partly caused by solar’s low starting point. Other sources of renewable energy, such as wind power, or the burning of liquid biofuels like ethanol, still represent a bigger share of the country’s renewable energy. In fact, solar doesn’t even come close to the generating capacity of most of its competitors:

A graph shows the generating capacity of the United States' renewable energy supply.

This serves as a good reminder that even though solar is ascendant, it’s not the only source of renewable energy. Still, if it continues to grow at this rate, solar might eventually be able to supplant other energy sources as the leader in renewable power.

Those efforts are likely to be buoyed by the Department of Energy’s plans to redesign the electric grid to better handle solar power, and to financially support companies working to develop solar technologies.

They could also be helped by the rise of batteries that can support the existing infrastructure. Tesla is embarking on the latest battery storage project in the world later this year, which could benefit solar because the technologies are often used together to great effect.

EIA’s report shows that solar has a way to go before it can catch up with other renewable energy sources. But it’s clear that as it continues to grow in popularity, and as consumers start to embrace solar panels more than ever before, solar is poised to become the future of clean energy in the United States.

Photos via Energy Information Administration, U.S. Department of Energy