Until late 1999, a Colorado-based Air Force software testing center had to shut down every time a lightning storm came within 10 miles of the facility. If a storm had ever caused a power outage, the old backup power system couldn\u2019t have provided electricity fast enough to keep systems operational. But the installation of two innovative CleanSource DC units?from Austin, Texas-based Active Power, a manufacturer of alternative backup power products?now lets the facility remain open during the storms that frequent the area. The systems, chosen because of their low price and refrigerator-size footprint, work parallel with more expensive, larger battery installations that are double in size. The units combine uninterruptible power supply (UPS) electronics with a flywheel energy storage system to replace traditional backup batteries. The flywheel, which resembles an 11-inch high, 30-inch diameter hockey puck, spins at 7,200 rpm using just a small amount of current from the power grid. When the grid supply sags or shuts off, the system instantly converts the wheel\u2019s kinetic energy into electricity through a generator. That lets the facility ride through the 15 to 30 seconds it takes for backup generators to take over.In the Air Force\u2019s case, the two systems have already ridden through numerous sags and outages. "There\u2019s no way to relate it to money, because it\u2019s a military mission, but in terms of man-hours...it\u2019ll save us about $6 million [in lost productivity] over three years," says a senior source at the center.Flywheels overcome the limits of batteries traditionally used for bridging outages. A flywheel can provide ride-through power?small bursts ranging from less than a second to several seconds?several million times during its 20-year lifetime; a bank of batteries provides a much more limited number of discharges throughout a life expectancy that rarely exceeds four years.It is also simple to maintain one of Active Power\u2019s systems: Replace the air filter annually and the ball-bearing cartridge once every three years. Battery-based UPS maintenance requires cleaning hundreds of terminals every three to six months and frequently monitoring fluid levels. The flywheel can also operate in temperatures (-4 F to 104 F) that degrade the capacity and life of batteries, and it lets employees escape the hazards of dealing with the toxic chemicals found in batteries.Spurred on by the current system\u2019s success, the Air Force is considering adding newer Cat UPS units, manufactured by Active Power for Peoria, Ill.-based Caterpillar, which integrate a flywheel directly with a generator. "We\u2019re looking down the road, hoping that the military will eventually say, \u2019OK, we don\u2019t need to use batteries,\u2019" says our source. "The batteries have always been the weakest link in a UPS system. Recurring costs of maintenance and replacement of battery cells is what you\u2019ll spend most of your money on." Basking in the Green GlowAnother way to sidestep batteries is to install a distributed generation system, such as a photovoltaic (PV) system tied into the power grid. "The power grid essentially acts as a battery," says Janice Lin, director of business development at PowerLight. Net metering programs allow private power generators?companies and even households?to sell the excess power they generate back to the power companies. (The specifics of such programs vary by state, but PowerLight says it can help companies work through the details.)PowerLight\u2019s PowerGuard rooftop system combines photovoltaics with roofing materials. The panels fit together like pieces in a giant jigsaw puzzle, and the company can quickly install the modules on a flat rooftop. For example, PowerLight claims to have completed installation of a 125kWh system on its own Berkeley, Calif., factory in approximately six hours.Even electricians are getting in on the PV act. In April, PowerLight put a system on the roof of the International Brotherhood of Electrical Workers Local 332\u2019s new San Jose, Calif., headquarters. The facility, which San Jose Mayor Ron Gonzales and the City Council have designated as a "green building" model, will be used to train union members in PV installation.The recent power problems in California have garnered a lot of attention for conservation issues, but some companies got involved in alternative energy long before the rolling blackouts. "Our commitment to installing a PV system at Neutrogena preceded the recent energy crisis in California," says Senaka Nanayakkara, director of facilities at Neutrogena. Neutrogena is participating in the Los Angeles Depart-ment of Water and Power Solar Buy-Down Program, and it is receiving kudos as a model corporate citizen by becoming the first large company in the area to go solar. Installing a PV system at its Los Angeles headquarters will reduce power-production-related air pollution and lighten the load on the power grid. PowerLight designed the system, which covers approximately 24,000 square feet of roof area. When either of the buildings at headquarters requires more power than its 100kWh PV system can generate, it draws power from the grid; any surplus goes into the grid to be used by others, and Neutrogena expects to receive nighttime rebates on its power bill. (For more on power alternatives, see "Think Outside the Grid," May 1, 2001.)PowerLight claims that its systems don\u2019t benefit companies located only in sunny California. The company has also installed systems in Canada, New York, Wisconsin and Germany.Fueling the FuturePV cells require sunlight, and flywheels only hold the fort until a noisy, polluting generator can kick in. But fuel cells may ultimately offer a cleaner, easier solution. Fuel cells vary in type, but the most common produce electricity by breaking hydrogen molecules into protons and electrons. A flow of oxygen draws off the hydrogen protons through a special membrane, allowing the electrons to be harnessed as electrical current. The chemical components then come together to form water.International Fuel Cells, a South Windsor, Conn.-based company that supplies fuel cells used in the space shuttle, produces PC25 commercial systems that provide 200kWh each. Five such fuel cells went to work at the Anchorage Mail Processing Center in Anchorage, Alaska, in 2000?the largest fuel cell installation to date. The system works parallel with the local power grid, but in the event of a grid failure, the fuel cells can continue to operate independently. Some of the 700,000 BTUs of heat that the fuel cells produce as a byproduct end up warming the facility, further reducing overall energy costs. Since the end products of fuel cells are electricity, heat and water, this technology is also considered environmentally friendly?a plus in an environmental hot spot like Alaska.Paying the PriceThe biggest drawback to the Anchorage Mail Processing Center fuel cell system may be the price. The 1,000kWh system cost $5.5 million?undoubtedly more than many companies will pay if they can already get reliable power from the local utility and need the standalone system merely for backup (the post-office system was partially funded by the Department of Defense and the Army Corp. of Engineers). Fuel cell vendors hope that the support of the military and other government agencies?as well as wider commercialization?should help bring fuel cell costs down.In the meantime, power problems will continue to cost everyone. A Sandia National Labs study estimates that power disruptions, from brief sags to long outages, cost the United States $150 billion annually. And while fuel cells may not be cheap, the other technologies discussed in this article fare better in the cost-benefit analysis.Active Power, for instance, can install a 250kWh CleanSource DC system for $45,000, about the same as a battery array of similar capacity; savings arise when you don\u2019t have to replace the batteries a few years down the road. The Cat UPS has an installed price tag of $90,000 per 250kwh, about the same as a battery-based system. The savings begin adding up quickly, since Cat UPS\u2019s 10-year operating cost of about $200,000 compares favorably with $400,000 for the battery system of equal power, according to Joe Pinkerton, president and CEO of Active Power. While not yet as cost-effective as traditional technologies, the cost of PV systems has dropped tenfold throughout the past 25 years, and governments are also providing valuable subsidies for more environmentally friendly technologies, according to a recent Goldman Sachs report. The Los Angeles Department of Water and Power Solar Buy-Down Program, for example, provides incentives of $5 per kilowatt-hour if the system uses locally manufactured products, or $3 per kilowatt-hour if the parts are from elsewhere. Neutrogena\u2019s $1.4 million system qualifies for the higher incentive (up to $1 million total) since Siemens Solar, which has a local facility, provided the modules.And for those who were sitting in Silicon Valley when the first rolling blackout hit California in January, uninterrupted power is likely to seem a bargain at almost any price.