What happened 

Shares of megawatt-scale fuel cell company FuelCell Energy (NASDAQ:FCEL) jumped as much as 22.9% in early trading as the stock's tremendous run continues. At 10:55 a.m. EST, shares are still up 17.2% in volatile trading but holding big gains for the day. 

So what

To be clear, this is another speculatory move from FuelCell Energy traders. There isn't any news moving the stock today, but the company is going to announce earnings before the market opens tomorrow. Traders are obviously making their bets before the market closes today, and they're hoping for a great quarter. 

Fuel cell installation from FuelCell Energy.

Image source: FuelCell Energy.

Analysts expect revenue of $11.5 million and an $0.11 loss per share, so beating those marks will be key. But investors will also want to watch contributions from a deal with ExxonMobil, if a partnership with E.ON Business Solutions is paying off yet, and where backlog stands. Management said in November that project backlog is $2 billion, so look for a bigger update on those projects. 

Now what

FuelCell Energy's stock has been on fire in since early December and is one of the top-performing stocks on the market. But the reality is that the growth has been built on just one quarter of surprisingly good results, which was primarily the result of the recognition of $10.0 million in revenue from the ExxonMobil licensing deal, which was a one-time event. 

This year, the company needs to prove it can grow revenue and generate positive cash flow. That's proven to be a tall task for a company that's reported an operating loss and paid for it by diluting shareholders and issuing debt for more than a decade. 

FCEL Operating Income (TTM) Chart

FCEL Operating Income (TTM) data by YCharts

Given the speculative nature of FuelCell Energy's operations today, this isn't a stock I'm going to jump in on. But the long-term story for investors may be starting to turn around, and tomorrow's earnings report will tell us a lot about how fast operations are progressing.