Once upon a time, Power-One (Nasdaq: PWER) was a small builder of power inverters for industrial and technical uses, and its largest customer was Cisco Systems (Nasdaq: CSCO). Then the company bought part of an even smaller operation named Magnetek and discovered the joys of building power inverters for use with solar panels. Power-One hasn't looked back since.

In the just-reported third quarter, Power-One's solar inverter division multiplied its year-ago sales by 7.3 times and helped the company triple its revenue overall. Economies of scale are big in manufacturing industries like this one, so last year's $0.03 loss per share exploded into a $0.40 net profit per share. All of this took Wall Street by surprise; Power-One exceeded estimates for the fourth quarter in this report and then proceeded to raise its outlook even further.

Management expects a strong 2011 for solar power in general, particularly in the Chinese and North American markets, with Europe taking a breather. Power-One already has manufacturing facilities in China thanks to that Magnetek purchase and recently opened a couple more in Canada and the U.S. Other facilities are planned for next year in order to keep up with rampant demand.

Power-One has moved from a 5% market share in the solar inverter market last year to an 11% share today. It is now the second-largest supplier of these products to a hungry solar industry, after pink sheets denizen SMA Solar Technology. The company is tight-lipped about whose solar panels match up with its power inverters, but it's a flexible technology that enables Power-One "to work agnostically with any panel manufacturer via thin film or crystalline." That opens the door to China-based crystalline panel leaders LDK Solar (NYSE: LDK) and JA Solar Holdings (Nasdaq: JASO) and thin-film giant First Solar (Nasdaq: FSLR) right next door to Power-One's new factory in Arizona. There should be no problem finding plenty of installation projects for this company's products, given the wide compatibility profile.

Power inverters are typically not the first thing you think about when looking for green energy stocks, but Power-One proves that there's gold in those boring electrical components. The stock started out flying high last Friday thanks to the stellar report, but lost the entire 16% spike and more almost immediately after the opening bell rang. All things considered, the stock has nearly tripled over the last year.

If you see renewed gains ahead, you can give Power-One a thumbs-up rating in CAPS. Me, I'll settle for adding the stock to my watchlist so I can get a better feel for the opportunity before doing anything rash.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. First Solar is a Motley Fool Rule Breakers selection. The Fool has written calls (bull call spread) on Cisco Systems. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.