SunPower (SPWR -1.02%) is known around the solar industry as the manufacturer of the most efficient and some of the most expensive panels in the industry. But it's also one of the largest utility-scale project builders in the world and has an emerging business in residential solar. That's where that high efficiency can overcome high costs and create a lower cost of energy than competitors. 

Some may be surprised to find out that SunPower's 44 MW of residential solar installed last quarter is behind only SolarCity (SCTY.DL) in the U.S. If we look globally, the 128 MW it installed makes it the No. 1 residential solar company in the world. 

SunPower is also winning against First Solar (FSLR -1.46%), which has long had some of the lowest costs in the industry. Over the past year, SunPower's margins have been rising and it's running factories at capacity while First Solar's margins are down and it's making just 83% of the panels it could. 

In the video below, solar analyst Travis Hoium covers how SunPower is winning in solar and what the next big steps are for the company.