What happened

What went way down earlier this week (oil prices, that is) are going back up today (also oil prices). Naturally, that's good news for oil stocks -- but it turns out it's pretty good news for alternatives to oil, as well.

In late-day trading, shares of solar stocks SolarEdge (NASDAQ:SEDG) and Vivint Solar (NYSE:VSLR) are up 10.4% and 8.7%, respectively, as of 3:25 p.m. EDT. Likewise, fuel cell stocks are up, too, with FuelCell Energy (NASDAQ:FCEL) notching 8.5% gains, and Bloom Energy (NYSE:BE) rebounding 18.9%.

Four arrows pointing up

Image source: Getty Images.

So what

What's driving these stocks up? Eliminating the obvious choices first, it doesn't appear that there's any obvious stock-specific news behind any of these massive runs. In the cases of solar-inverter maker SolarEdge and solar-panel installer Vivint, there's no news whatsoever to explain why either stock should be worth 10% and 9% more today than they were worth yesterday.

FuelCell Energy issued a press release touting the beginning of commercial operations at its "SureSource 4000 fuel cell project located at Triangle Street in the city of Danbury, Connecticut." But no value was ascribed to the project -- and in any case, that press release is already more than a day old. 

Likewise, Bloom issued a press release describing the "rapid deployment of two fuel cell microgrids" in California -- again with no value ascribed. But again, this is yesterday's news. It certainly doesn't seem like the kind of thing to drive a near-19% gain in stock price for Bloom.

Now what

What does explain why these stocks are soaring?

Well, consider this: The price of WTI crude oil spiked 21% higher in Wednesday trading, and the price of Brent crude is up a healthy 7.5%. In each case, there are reasons for the increase -- the expiration of May-delivery oil futures contracts and bellicose statements from President Trump, issued in the direction of Iran.

Whatever the reasons, oil prices are rising, and whenever that happens, alternatives to oil become (relatively) more economically attractive. Investors' reactions in bidding up shares of alternative energy stocks in the solar and fuel cell sectors, therefore, does have some logic to it.

Personally, I question the logic of bidding up shares of unprofitable Bloom Energy more than profitable SolarEdge -- and bidding up unprofitable Vivint nearly as much. If you ask me, profitable companies are simply better investments than unprofitable ones.

If you're looking to join in on today's rally, of the four alternative energy stocks surging today, I think profitable and fast-growing SolarEdge is probably the best bet.