(Reuters) - U.S. solar companies First Solar Inc
First Solar, the biggest U.S. solar panel maker, cut its full-year revenue outlook, however, citing unspecified weather-related disruptions in its supply chain.
The company's shares fell 5 percent after the bell, while SunPower shares were up about 1 percent.
Both companies are shifting their focus to building solar power plants as they try to overcome stiff competition in the panel business from low-cost Chinese producers.
"They are two of the more advanced project developers, but the thing that ties them together is just the question of being able to survive the Chinese onslaught," said Stephen Simko, solar industry analyst with Morningstar.
SunPower's revenue from North America rose 36 percent in the third-quarter, helped by solar projects in California and as expanded in the market for residential solar power systems.
Solar panel prices have fallen more than 30 percent this year alone, forcing companies such as First Solar and SunPower to turn their attention to more lucrative businesses.
First Solar's cadmium telluride panels had long been the cheapest in the solar industry, which is dominated by silicon-based panels. But the Tempe, Arizona company's advantage has eroded due to the price cuts on traditional silicon panels.
Chinese panel makers have rapidly ramped up production over the past decade, creating a global glut that sent prices into a tailspin, forcing many European and U.S. solar companies to shut plants and sending some of them into bankruptcy.
Both First Solar and SunPower have taken the ax to costs to improve margins.
SunPower, which is majority owned by France's Total SA
"Total at some point might become impatient and push them to do a further restructuring ... I doubt they are comfortable with losing $100 million every quarter," said Simko.
SunPower forecast adjusted fourth-quarter profit of between zero and 25 cents per share on revenue of $700 million to $900 million.
Analysts, on average, were expecting earnings of 11 cents per share, on revenue of $798.96 million, according to Thomson Reuters I/B/E/S.
SunPower reported an adjusted profit of 3 cents per share, confounding expectations for a loss of 11 cents per share.
First Solar shares closed at $24.73 on Thursday on the Nasdaq. SunPower shares closed at $4.56.
(Reporting by Swetha Gopinath in Bangalore and Nichola Groom; Editing by Sreejiraj Eluvangal and Ted Kerr)