The latest order came from a division of Tyco International Ltd., which had already purchased 116 units. Tyco sold the fuel-cell systems to a single telecommunications customer, which neither firm has identified.

To date, Plug has sold 174 of the $15,000 to $20,000 GenCore units. And orders for 100 units or more are expected in the coming months, Plug's chief executive, Roger Saillant, told analysts and investors in a conference call Wednesday. He declined to be more specific.

But Saillant said he was comfortable with his goal of selling 300 GenCore units this year.

He also said a proposed tax credit for GenCore buyers in the energy bill moving through Congress would drive sales.

"The 300 (unit) milestone does not assume a tax credit, but a tax credit would surely stimulate demand further," he said.

Plug shares (Nasdaq: PLUG) closed Wednesday at $7.09, up 9 cents. Volume was heavy: 1.37 million shares.

The GenCore system is used by telecommunications companies as backup power, especially at sites like cellphone towers. The fuel cells are marketed as replacement technology for lead-acid batteries.

The Latham-based company also announced financial results for the second quarter and first half of 2005.

It lost $10.9 million, or 15 cents a share, in the second quarter, compared with a loss of $11.3 million, or 15 cents a share, in the year-ago quarter. For the half, Plug lost $23.4 million, or 32 cents a share, compared with $23.3 million, or 32 cents a share, in the first six months of 2004.

Revenue for the quarter remained flat: $3.7 million, unchanged from the year-ago quarter. Revenue in the first half was $6.9 million, compared with $7 million last year.