What: Shares of solar manufacturer First Solar, Inc. (NASDAQ:FSLR) jumped as much as 19% today after the company released second-quarter earnings.

So what: Quarterly sales rose 65% to $896.2 million, and net income jumped from $4.5 million to $94.5 million, or $0.94 per share. Analysts only expected $0.36 per share in earnings, so results easily beat expectations.  

Full-year guidance of $3.5 billion to $3.6 billion in sales and earnings of $3.30 to $3.60 per share were also ahead of expectations. First Solar is finally selling some of its projects to its new yieldco, 8point3 Energy Partners, and that's having an even bigger effect on earnings than Wall Street expected.

Now what: An increase in efficiency has dramatically changed First Solar's competitive position, and the financial results are starting to show that. But having a yieldco to drop assets into has also increased sales and margins for First Solar. This is one of the best-positioned solar companies in the industry, and with the financial performance the company is now putting up, I think this is a great long-term buy for investors.