What happened 

Shares of First Solar, Inc. (FSLR 0.68%) went up as much as 19.6% today after the solar leader reported first-quarter earnings results. At 1:20 p.m. EDT, the stock was still up 13.2% and holding gains for the day. 

So what

Revenue rose 1.8% to $891.8 million in the quarter and net income plunged from $195.6 million a year ago to $9.1 million, or $0.09 per share. But results easily beat analyst estimates of $667.8 million in revenue and a loss of $0.13 per share. 

First Solar utility scale solar farm.

Image source: First Solar.

What really got investors excited was management's increased 2017 revenue guidance by $50 million, to $2.85 billion to $2.95 billion, and non-GAAP earnings-per-share guidance by a quarter, to $0.25 to $0.75. Higher sales of solar system components and more robust sale prices for projects caused the results to surpass expectations.

Now what

2017 was predicted to be a very bad year for solar companies, which is why First Solar's management is taking this time to upgrade its equipment from Series 4 modules to Series 6. And now demand for both Series 4 modules in the short term and Series 6 modules in the long term may be higher than anyone anticipated. With such negative sentiment for solar stocks coming into 2017, this recovery may be just the beginning.