Utility Fired Up About Using Wood at Power Plant

May 30 - Gazette, The; Colorado Springs, Colo.

Train cars loaded with sawdust could become nearly as common on the Front Range as coal cars.

Preliminary results from a renewable energy study show Colorado Springs Utilities' downtown Drake Power Plant would require little or no modification to be stoked with cleanburning wood byproducts.

Although shipping costs remain an issue, supplies appear adequate to generate 40 megawatts of power, about 5 per- cent of Springs Utilities' peak summer demand.

"If it's cost effective and can lower emissions and balance the diversity in our portfolio, that's a good thing," said Drew Rankin, Utilities' energy supply manager.

Viability of burning wood is one of several early findings from a $265,520 study about renewable energy sources.

The Black and Veatch study, to be completed in mid-June, is the first commissioned by Springs Utilities to analyze re- newables' technical and economic factors.

Besides wood, the study looked at biogas, with positive results, and wind energy, which fared poorly.

The study was a byuct of Amendment 37, a measure that mandates utilities use renewable energy for a portion of total retail sales. The law calls for renewable sources to constitute 3 percent by 2007, 6 percent by 2011 and 10 percent by 2015.

Springs Utilities will maintain those thresholds until 2010, based on its own hydroenergy production and purchase of wind power from a Loveland company.

After that, the utility will need more energy from renewable sources.

Rankin said the utility has issued a request for proposals to purchase renewable energy credits from other producers, which is allowed under Amendment 37. The credits are produced by utilities that are exceeding the renewable energy goals.

Still, the study might give the utility other options to construct a portfolio of energy sources that are costtive, reliable and environmentally responsible, Rankin said.

Biomass shows promise after 750 tons of sawdust and wood chips were fed into Drake over the past four months, he said.

"Those results have been positive," he said, adding that larger particles posed a problem and would need to be processed into smaller pieces if wood is used regularly.

Although coal produces 25 percent more heat, wood burns cleaner, Rankin said. Carbon monoxide dropped by more than a quarter when a small amount of biomass was added.

In addition, testing has shown no significant changes in boiler airflow, temperature and other mechanical functions when a 5 percent biomass mix with coal is used.

Utilities is so pleased with the results the department may apply for a permanent permit to burn biomass at Drake. "We will also most likely begin testing at Nixon based on these positive results," said Utilities spokeswoman Rachel Beck.

Shipping wood fuel by rail, the most logical method, could be too expensive, Rankin said.

The city also needs to secure reliable sources to supply a steady supply -- up to 500 to 600 tons per day of sawdust, limbs, shipping crates or other wood waste to generate 40 megawatts of power.

Black and Veatch identified 403 potential sources for biomass, among them several local firms, such as Rocky Top Resources, which supplied the materials for the Drake test, and WELCO, International Wood Works and Lumber Specialties. Similar companies operate in Pueblo, Florence, Bailey, Trinidad and Montrose.

The city also is in touch with a furniture maker in Utah that generates 60 tons of sawdust per day.

Besides generating power, using biomass accomplishes another goal as well.

"These wood products are landfilled or they (producers) have trouble getting rid of them," Rankin said. "This is a possible beneficial use."

Although wood wouldn't constitute a large portion of total production, even a small amount could prove worthwhile. For example, the city's hydroelectric facility in Manitou Springs, which recently observed its 100th anniversary, produces only 5.6 megawatts.

"While that seems pretty small to the total, it's all additive," he said. "All that energy we produced for the first 100 years was a low-cost supply for our customers.

As for biogas, Rankin predicted the utility might begin this year or next capturing, treating and reinjecting the substance into the natural gas system from the city's solid handling disposal facility 20 miles south of Colorado Springs. The facility essentially composts sludge from water and wastewater treatment processes.

"Instead of just flaring that off into the atmosphere, we're examining how we can make better use of that biogas for our customers," he said.

But tests didn't bode well for wind energy, Rankin said.

After collecting a year's weather data at Clear Springs Ranch 20 miles south of Colorado Springs, analysis shows turbines would operate at 18 percent capacity, far less than the industry norm of 38 percent. Wind power would cost about $100 per megawatt, compared with a Lamar wind farm's rate of $55 per megawatt, making it more attractive for Springs Utilities to buy wind power elsewhere.

"It is discouraging," Rankin said. However, he said utility officials haven't bagged the idea and are mulling wind turbines for the city's water treatment plant at the Air Force Academy, where gusts are more constant.

CONTACT THE WRITER: 636-0238 or pam.zubeck@gazette.com