The company is selling 17.9 million shares and will raise $251 million in the offering. The new funding will enable the company to continue to grow its solar sales and compete in an increasingly competitive marketplace.

Founded by entrepreneurs Ed Fenster and Lynn Jurich in San Francisco eight years ago, Sunrun installs and finances solar panels on the rooftops of homes. Like competitors SolarCity and Vivint Solar, Sunrun offers customers no and low money down deals, and customers pay a monthly electricity bill for the solar power over many years.

Sunrun is the rare venture capital-backed energy company that has made it to an IPO. Over the course of its lifetime Sunrun has raised around $265 million in funding from investors including Sequoia Capital, Foundation Capital, Accel Partners and Madrone Partners, a firm affiliated with the Walmart family.

The market for solar rooftops is exploding in the U.S. Last year about a third of all the new electricity generation that came online in the U.S. was from solar. This year 8,100 megawatts of new solar panels are expected to be installed in the U.S. by the end of the year (1,000 megawatts is the equivalent to a large gas, coal or nuclear power plant).

Sunrun has attracted 80,000 solar customers, and at least half of those are in California. Last year the company bought the residential division of REC Solar, as well as distributor AEE Solar and racking manufacturer SnapNrack.

But the solar installation industry is becoming increasingly competitive and consolidated, and is cash-hungry. While Sunrun’s revenues more than tripled to $198.6 million in 2014, up from $54.7 million in 2013, the company posted a loss of $162.6 million in 2014, up from a $68.6 million loss in 2013.

Solar installers are also rushing to sign up new customers because an important federal subsidy — the solar investment tax credit (ITC) that provides a 30% tax credit per installation — will fall to 10% by the end of 2016.