SolarCity looks to raise $123.5 million by selling notes by Katie Fehrenbacher @FortuneMagazine 11:32 AM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Installing solar panels on rooftops is a cash hungry business. On Wednesday, solar installer and financier SolarCity announced that it plans to sell $123.5 million worth of notes, backed by its solar assets, in a private offering. The debt is supposed to be repaid by February 2022. SolarCity has raised money in this way multiple times over the past two years. The news, which comes just hours before SolarCity plans to announce its second quarter earnings, highlights what a tough market the solar installation and financing business has become. SolarCity is run by brothers Lyndon and Peter Rive, and backed by their cousin Elon Musk, also the CEO of Tesla and SpaceX. The solar installation industry is consolidating and companies are trying to get as large as possible to use big balance sheets to pour money into marketing and sales leads. For example, huge clean energy company SunEdison is buying up solar installer Vivint Solar, while Sunrun, another Silicon Valley-backed solar installer startup, plans to go public. While the market was led by startups a few years ago, in recent years large companies like SunPower and NRG Energy have moved in. The market is maturing as the costs of the solar panels, gear and installation have come down dramatically. Now it’s a race to the bottom to see which companies can sell large volumes of solar deals at low prices. SolarCity is the biggest solar installer in the U.S., so it’s a leader in bringing in new customers. But it’s also piling on a large amount of debt. Sign up for Data Sheet, Fortune’s daily morning newsletter about the business of technology.