What happened

Renewable energy stocks sank Thursday morning, and for a variety of reasons.

As of 10:45 a.m. ET, shares of charging network operators Blink Charging (BLNK 2.24%) and ChargePoint (CHPT 3.49%) are down 6.7% and 6.8%, respectively, while hydrogen fuel cell company Plug Power (PLUG 5.69%) continues to give back yesterday's gains, and is in fact down another 7.5% today.

So what

Yesterday, if you recall, Plug Power went on something of a wild ride, first rising several percentage points before ending the day with a loss, as investors first reacted to a positive assessment of the company's prospects from The Wall Street Journal -- then seemingly rejected that assessment entirely. Today, the selling at Plug Power continues despite there being no actual bad news to explain it.

Presumably, the reason is that investors are concerned that Plug Power might not meet analysts' forecasts for achieving profitability by 2025. The good news is that management plans to give a business update on Jan. 25. With any luck, that update will give us a better picture of how close Plug is to reaching its goals.  

The situation with Blink and ChargePoint is more interesting. Yesterday, peer charging network operator Volta announced it will sell itself to oil giant Shell plc for $169 million. The news sent Volta shares surging 22% in a single day -- but for Blink and ChargePoint, the news is ominous.  

As recently as two years ago, around the time of its SPAC IPO, Volta stock was valued 15 times higher than the price Shell is paying today. Indeed, just one year ago, Volta stock was worth 6x more than what Shell is now paying. But now the stock is worth much less -- at most $169 million (what Shell wants to pay), or even less than $150 million (the stock's current market cap).

Now what

If that's the case, though, what does it mean for Blink and ChargePoint?

Consider that Shell's $169 million purchase price values Volta at roughly 3.4 times trailing sales. Yet Blink stock is currently selling for closer to 15x sales at its current $690 million market capitalization, and even ChargePoint stock is valued at 9.5x trailing sales -- nearly a 3x premium to Volta's valuation. (Clearly, none of these three stocks are anywhere near profitable today).

The implication of the price Shell is paying for Volta, as compared to what most investors are paying for similar stocks Blink and ChargePoint, is either that Shell just scored the bargain-basement deal of the century, or that Blink and ChargePoint stocks are wildly overvalued.

Investors today seem to be worried that the latter conclusion is the more accurate one. Thanks to Shell's very public demonstration of what charging stocks are really worth, investors are reworking their math -- and selling their charging stocks before their prices fall even further.