Experts predict that dollar sales of fuel cell technology will eventually reach the hundreds of billions. But after the stock market binge of the late 1990s and the hangover that followed, companies need a plan for economic viability that bridges today's technology with expectations of a reinvented energy marketplace.

"Right now the fuel cell industry is in a state of flux," says Eric Prouty, an energy technology analyst at Boston-based investment bank Adams Harkness & Hill Inc. "Over the last few years, many pure-play (fuel cell) companies went public, but over time we see a lot of consolidation as companies move out of the R&D phase."

To survive, companies are seeking short-term markets for their fuel cell technology or are articulating a strategy to turn their research into marketable products. Devices containing fuel cells, which use chemical and electrical processes to convert hydrogen to electricity, are being developed to generate electricity and as replacements for internal-combustion engines in vehicles.

Gary Mook, president and CEO of Westwood-based power company Acumentrics Corp., says fuel cells make up a disruptive technology that will shake up the energy industry in much the same way personal computers reinvented the mainframe-dominated computer industry in the 1980s.

But in the short term, his company has found a more immediate market for fuel cells: back-up power supplies. Acumentrics' core business is battery-powered, uninterruptible power supplies. It recently launched its broadband powering unit, a product that uses fuel cells to generate and back up electricity in distributed cable power boxes located every few miles.

"The key for the product is that it has to be cost-effective," Mook says, adding that the company is struggling to meet demand. "We worked very hard on the product and manufacturing processes so we could be cost-effective right out of the gate."

The company, founded in 1994, has used the cash flow from its battery and flywheel back-up power businesses to fund research in its solid oxide fuel cell technology, which converts hydrocarbons, such as natural gas, into hydrogen and then electricity. Following the PC industry model, its strategy is to build production volume by building relatively small-scale energy devices and constantly enhancing its technology.

"We see a big fall-out in the sector -- the funding has dried up," Mook says. "Thhe companies that are successful have other businesses they can rely on."

Energy company Nuvera Inc., with headquarters in Cambridge and Milan, Italy, is taking a more traditional, technology-company approach to growth. The company was formed in 2000 by combining the PEM (proton exchange membrane) fuel cell stack from Italian company Gruppo De Nora and the fuel processing technology from Epyx Corp., which was an offshoot of A.D. Little.