Shares of Vivint Solar Inc. closed at $16.01 on their first day of trading Wednesday, giving Blackstone Group LP, the world’s largest alternative asset manager, and other investors a more than $1.1 billion unrealized gain on their two-year-old investment in the solar-panel installer.

The company sold 20.6 million shares for $16 apiece Tuesday, pricing them at the low end of the marketed range. Some of the proceeds will be used to repay debt, regulatory filings show.

“We believe that this capital will take us through 2017 with the current growth rates,” Chief Executive Officer Gregory Butterfield said on CNBC. “In three years, we’ll become the second-largest residential solar company” after SolarCity Corp. Vivint Solar will be cash flow positive “around the end of 2017,” Butterfield said.

Vivint Solar was created nearly three years ago under Vivint Inc., a provider of residential-security services and technology that allows customers to control features in their homes remotely. Blackstone and a group of co-investors acquired Vivint’s three main assets in a $1.9 billion leveraged buyout in 2012, investing $714 million of equity.

The Blackstone-led group, which included Summit Partners, injected about $195 million in Vivint Solar, including $78 million this year, according to filings. Their stake was valued at $1.3 billion at the end of trading, nearly seven times what they invested.

The group sold no shares in the IPO, and will hold a 78 percent stake in the company after the offering, filings show. The group owned 97 percent of the company before the sale.

Blackstone spokesman Peter Rose declined to comment on the offering and Blackstone’s profit.

Solar Leases

Based in Lehi, Utah, the company posted revenue of $6.17 million last year, mostly from selling solar operating leases, filings show. The company offers 20-year contracts for electricity powered by solar energy that costs customers as much as 30 percent less than their current utility rates.

Vivint Solar’s IPO follows a surge in installations of rooftop power systems. Developers installed 792 megawatts of photovoltaic panels atop U.S. homes last year, up 60 percent from 2012, according to the Solar Energy Industries Association.

Shares of SolarCity have jumped 58 percent over the past year, as the San Mateo, California-based company continued to add more megawatts of new residential and commercial solar systems.

Vivint’s shares are listed on the New York Stock Exchange under the symbol VSLR. Goldman Sachs, Bank of America Corp. and Credit Suisse Group AG managed the offering.