The stock advanced nearly 17% shortly after the market opened, then settled back. At last check it was off nearly 10% at $2.26.
The company on Monday said it had launched a 2.8-million-megawatt fuel-cell project at a wastewater-treatment plant in Tulare, a city in central California. The plant will convert biogas into electricity using a chemical reaction rather than combustion.
"Globally, our solution delivers renewable and affordable power on a scale that is meaningful to communities and to the utilities that serve them," said Jason Few, president and CEO of FuelCell, in a statement.
The Danbury, Conn., company's stock price has shot the moon over the past two months, rising tenfold from early November, when it was trading at 27 cents a share.
Since Dec. 26, when FuelCell closed at 82 cents as share, the stock has tripled.
FuelCell's stock-price ride kicked off Nov. 6, when the company reached a two-year, $60 million deal with ExxonMobil (XOM) - Get Report. The effort aimed to further boost the effectiveness of the company's carbonate fuel cell technology in order to deploy it to capture carbon dioxide at industrial plants.
The oil giant noted it was moving ahead with plans for a pilot project to test the enhanced fuel cell technology at one of its facilities.
FuelCell Energy's stock price doubled the day of the announcement, to 54 cents a share.