What happened 

Shares of solar energy stock Enphase Energy (ENPH 0.86%) jumped as much as 10.8% today after getting some positive news about its energy storage business. At 12:10 p.m. ET on Monday, shares were up 10.1% and have been climbing all morning. 

So what 

Enphase announced this morning that it is expanding battery storage in Massachusetts through its network of dealers. The company didn't announce any new service, but said installers "have seen an increase in deployments" of Enphase microinverters and batteries as extreme weather and power outages hit the state over the weekend.

Home with large solar installation on the roof.

Image source: Getty Images.

This follows an announcement late last week that Enphase was partnering with Semper Solaris, an installer of solar and battery systems in California, to expand offerings across that state.

It hasn't hurt that the stock market overall is up today, and solar energy stocks in particular are rising sharply. After selling off for months, there's at least a little bit of a bounce back in both growth stocks and solar energy, which shouldn't be overlooked today. 

Now what 

Today is another reminder that volatility is part of investing in the solar energy industry. Stocks like Enphase dropped sharply from mid-November to late last week, and Monday's gain is recovering only a small amount of those losses. But long-term investors need to keep in mind the trajectory of these businesses. 

Enphase is still growing as solar installations grow, and it's expanding product lines into energy storage and monitoring. These should help the company grow both the top and bottom lines over the long term, which is why I continue to be bullish on solar and Enphase Energy stock.