What happened 

Shares of FuelCell Energy (FCEL -2.57%) fell by as much as 14.3% in trading on Thursday after the company reported its fiscal second-quarter 2021 financial results. Shares floundered from the start of trading and were down 10.3% at 2:45 p.m. EDT. 

So what

For the period that ended April 30, FuelCell Energy's quarterly revenue fell 26% to $14.0 million and its net loss grew by 28% to $18.9 million, or $0.06 per share. Even adjusted EBITDA got worse, as its loss of $3.3 million a year ago grew to a loss of $11.3 million.

Hydrogen molecule in a bubble floating in the air.

Image source: Getty Images.

Analysts were expecting a loss of $0.05 per share on revenue of $19.2 million, so this was a big miss. Management explained away the drop in revenue as primarily the result of a decline in new module exchanges. 

Now what

Falling revenues aren't a good look for a company that operates in what is supposed to be a growing segment of the renewable energy market. But more concerning is that FuelCell Energy's backlog dropped by $20 million, or more than revenue, to $1.32 billion. Business isn't coming in as quickly as investors should be hoping for. As such, this $3.2 billion market cap alternative energy company looks like a highly risky investment.