A Collection of Articles
Edit

Energy

Little Engines That Can

Need power but don’t want to plug into a central electrical utility? Microturbines are flexing their muscles in niche applications.

While it’s probably still true that all politics is local, all power is not. Most businesses still rely on large, central electric-generation utilities for the juice to run their operations. But that’s changing. Faced with soaring prices, a doubling of demand in recent decades, and an aging power grid susceptible to blackouts, an increasing number of small- to medium-size businesses want local control over their power supply. That can mean literally putting it in their back yards.

Among the most economical, cleanest-burning and most fuel-efficient of the new power sources now emerging is the microturbine. Commercially available for only about three years, microturbines are small combustion turbines that consume natural gas or a variety of other fuels to produce 25 to 250 kilowatts of power. About as tall as a good-sized man and two or three times as wide, these compact dynamos-cousins of the engines that power jet airplanes-can be parked right next to a business facility.

Doug Herman runs a research program at the Electric Power Research Institute (a utility-funded R&D consortium) that focuses on “distributed generation”-alternative energy technologies located onsite at customer premises instead of at a centralized power plant. He says companies producing microturbines have concentrated on selling them into niche applications where customers are looking to save money on their electric bills and be assured of reliable, uninterrupted power.

Here’s how a microturbine works. First, the natural gas is first fed to a compressor, which is powered by electricity, says Gordon Savage, vice president for business development at Simmax Energy, a Huntington Beach, CA based energy systems company. About 3 kilowatts of the 80 kilowatts the microturbine generates is used to run the compressor. The compressed gas is then injected into the microturbine. This generates hot air that is then channeled through heat exchangers, Savage explains, which eventually transfer the heat to the hotel’s boilers.

Microturbines are particularly effective for slightly larger settings like manufacturing. According to mechanical engineer Bernard Kolanowski, author of the book Guide to Microturbines, hundreds can be linked to form a formidable power supply. Microturbines can also run on fuels that might otherwise be wasted. For instance, oil and natural gas are often found together when drilling takes place. To prevent an explosion, oil companies will extract and burn off the gas at a wellhead in a process called “flaring.” Microturbines can plug into the flaring pipe and run on the gas while also cutting way down on harmful hydrocarbons produced by flaring.

This is a common practice at offshore and outlying land-based oilrigs and boosting stations that lack access to power grids. The Canadian Natural Resources oil company is running five 30-kilowatt microturbines off of the natural gas flared from its Wabasca, Alberta oil well battery, according to Dan Boonstra, the authorized service provider for western Canada for Capstone Microturbines, a leading microturbine manufacturer. This station boosts natural gas from production wells down a pipeline to various utilities. The microturbines are the sole power source for the facility, which is situated out of reach of Canada’s power grid.

Microturbines are producing power at sites other than oil and gas fields, too. In most cases, the devices are deployed in cogeneration schemes to provide electricity for a facility while exhaust energy is used to heat air or water.

Take, for instance, Alloy Processing in Compton, CA-a metal plating company that anodizes components for aerospace systems. Anodizing makes parts like the bolts in an airplane wing resistant to corrosion over time. The process requires that parts be dipped in a special solution stored in huge tanks and maintained at a temperature of about 95 degrees C all day long. The amount of electricity required for this is considerable: peak electrical demand is 600 to 700 kilowatts, 300 kilowatts of which is dedicated to heating the anodizing tanks. At Alloy Processing, this resulted in monthly electric bills of $60,000 to $65,000 in the summer and $40,000 to $45,000 for the rest of the year, according to general manager and vice president Brian Leibl.

To save on electricity, says David Moard, President of Powerhouse Energy, a California supplier of distributed generation energy technology, Alloy Processing contracted with his company last April to install four linked, 60-kilowatt natural gas-fired microturbines. Now, in addition to supplying power for the entire plant, the microturbines also heat the solution in about half the tanks. According to Moard, Alloy Processing takes the waste heat of the microturbines and uses that to generate hot water, which in turn heats the anodizing solution to the necessary temperature. As a result, says Leibl, the company has cut its electric bill by about 80 percent. The total cost of the system, says Leibl, was about $550,000-one third of which was rebated to Alloy Processing from the state through a program encouraging companies to use alternative means of power. With the savings the company is seeing, Leibl says Alloy Processing is expecting an 18-month payback.

Microturbines can be especially cost-effective for small facilities such as apartment buildings, business parks, and hotels. For example, the Holiday Inn in Pico Rivera, CA has more than 350 rooms and does all its own laundry. This makes for a hefty electric bill each month, says Miguel Modrano, the hotel’s chief engineer. That’s why the Holiday Inn had Simmax Energy install a natural gas-powered 80-kilowatt microturbine. Simmax owns the microturbine-the hotel just pays for the power Simmax produces each month, says Timothy Bristol, general manager of the hotel.

According to Modrano, the microturbine produces about one quarter of the hotel’s electricity and four-fifths of its hot water. As a result, he says, the hotel does not have to run its hot water boilers as hard. What’s more, says Bristol, the heat it buys from Simmex is cheaper than the price for natural gas from a public utility. In total, the microturbine system lops about 35 percent off the hotel’s combined electricity and gas expenses, he says.

Microturbines can use as fuel energy sources that would otherwise be wasted, such as methane emitted from locations like public landfills. When brownouts hit California in 2000, the Los Angeles Department of Water and Power (LADWP) had to rededicate itself to finding alternative means of power. According to LADWP spokesman Randy Howard, LADWP has “one of the largest green power programs in the nation,” with about 43,000 paying customers. “Under the Green Power for a Green LA program, customers can choose to pay an additional 3 cents per kilowatt-hour for renewable energy,” he says. 

Late in 2000, LADWP installed 50 microturbines on the Lopez Canyon landfill. The 30-kilowatt microturbines were linked together to leverage the cumulative power of the devices in one power array. It was, at the time, the largest deployment of microturbines in the world.

Previously, the methane gas generated by the trash in the landfill had been extracted and flared. The flaring, and its attendant pollution, were necessary to prevent a gas buildup and explosion near adjacent populated areas, according to Robert Blue, the LADWP supervisor who oversaw the microturbines’ installation. LADWP tapped into the existing piping, he explains, so the methane could be diverted into gas compressors that feed the microturbines.

Blue says the system-including the microturbines, the gas handling system, additional electrical infrastructure, a new high voltage electric line, and a substation-cost a total of about $4 million. . Indeed, says Howard, “LADWP entered the project knowing the capital cost of development was higher than traditional generation.” He adds that LADWP is required by state law to spend 2.85 percent of its gross revenue every year-about $60 million-on “public benefit programs” such as new and renewable energy technologies. The microturbine installation “fit the definition for public benefit spending by reducing emission from flaring, generating electricity from a renewable fuel, and developing a new technology,” Howard says.

Blue says the solution “eliminates about 10,000 pounds of oxides of nitrogen a year-that is equivalent to the emissions of about 500 cars for the same period-and produces about 1.5 megawatts of electricity.” Howard adds that though the capital costs were substantial, the ongoing savings are also appreciable. “At current prices,” he says, “the cost of fuel from the landfill is one tenth that of natural gas.”

Other uses of microturbines are also emerging. A brick manufacturer in California is using the waste heat from its microturbines to heat its kilns. An injection molding manufacturer in New York is doing the same thing to air condition its plant. And a pasta maker outside Rome, Italy, dries its pasta with the exhaust from microturbines.

The next step for manufacturers, says EPRI’s Herman, is to develop a more standardized approach to installation of multiple microturbines. Look for this, he says, and the evolution of larger microturbines in the next five to 10 years-by which time these potent machines may well spin their way into a critical role in the energy picture.

Uh oh–you've read all five of your free articles for this month.

Insider basic

$29.95/yr US PRICE

Subscribe
What's Included
  • 1 year (6 issues) of MIT Technology Review magazine in print OR digital format
  • Access to the entire online story archive: 1997-present
  • Special discounts to select partners
  • Discounts to our events

You've read of free articles this month.