Biomass saves big bucks to heat and power rural schools

Rural entities across Alaska are looking for alternative sources of energy as a solution to unsustainable fuel and power bills. The Gateway School District, headquartered in Tok, appears to have found its answer to both in the woods.

In October 2010, the district installed a wood biomass-fired heating boiler system in Tok School. Before installing the boiler, district Superintendant Todd Poage said the school burned an average of 55,000 gallons of heating oil every year.

Heating oil currently goes for about $4 a gallon in Tok.

“When we just had the boiler section running in 2010 we were saving between $6,000 and $7,000 per month as compared to utilizing heating oil,” he said.

Those savings go right back into everyday operations.

“We started a lot of programs with stimulus funds we got four years ago and with the savings from this biomass project we put in preschools at every school in the district,” Poage said. “We hired a music teacher and were able to keep our music and counseling programs.”

Last fall, the district looked to further its energy savings by adding a low-speed electric steam turbine system to the steam boiler. The school uses about 530,000 kilowatts of electricity per year. The current rate for power in Tok is 52 cents per kilowatt. Poage said the school’s utility bill without the combined heat and power system, or CHP, is roughly $350,000 per year.

Assistant superintendant turned CHP project manager Scott MacManus said the addition of the steam generator to the boiler has been a challenge but he hopes to have the entire system fully operational by the end of November. Currently, CHP system is not running.

“The generator requires more wood so we’ve had problems with chip feeder, and integrating three power sources to all work together is difficult,” MacManus said. “It requires a lot of switches to work in unison.”

The second and third power sources are the school’s backup diesel generator and the traditional power grid.

According to MacManus, plans are for the school to generate an average of 70 kilowatts per hour to cover its consumption. That will allow for power to be sent into the grid when the system is generating more than the school needs and to draw from it at peak demand, such as when the gym lights are turned on.

MacManus estimated the CHP system will save the district more than $300,000 per year when it’s full up and running.

MacManus and Poage both stressed they’re not in the power business and that Alaska Power and Telephone, who supplies the area with power, understands the need for the system.

“This is not a pie-in-the-sky project. It’s about finding a long-term solution to an economic problem,” MacManus said.

Generating electricity will produce far more heat than the school can use and initial excess heat will be let-off to the outdoors. Hopefully, that be the case won’t be for long.

Gateway School District received $140,000 in legislative grants earlier this year to build a greenhouse alongside the Tok School. The greenhouse will be heated with surplus heat from the CHP system and provide fresh produce to the entire district.

“We have the design done and we just have to build it this spring,” Poage said.

The district spends $18,500 on produce every year. It estimates the 2,400 square-foot greenhouse could provide up to 20,000 pounds of produce and nearly eliminate its fresh grocery bill over a nine-month growing season.

A $2.8 million grant is also under review by the Alaska Energy Authority, or AEA, to extend a heat loop from the school to the Tok fire department, senior center, low-income housing and two state buildings, Poage said. The loop will use the remaining heat generated that the school cannot use.

“We can provide them with heat for half the cost they’re currently paying,” Poage said.

AEA has funded construction of biomass heating projects in Delta and Thorne Bay, along with Tok. In partnership with the U.S. Forest Service AEA has funded more than 30 pre-feasibility studies for similar projects since 2011, with another 16 scheduled for next year, according to AEA spokesman Karsten Rodvik.

In Tanana, the city shop, teacher housing and water treatment facilities have already received biomass upgrades thanks to AEA dollars. City Manager Bear Ketzler Jr. said the city’s school project is expected to be up and running before the new year.

“We have a number of properties already operating with biomass, but the is by far going to be the biggest biomass system in the community. For that matter, on the Yukon River,” Ketzler said.

The furnace is designed to cover 80 percent of the school’s heat at peak draw. That equates to a savings of roughly 80 gallons of heating oil on Tanana’s coldest days.

“The school normally burns about 15,000 gallons a year and that’s down from about 25,000 before we did the weatherization project a couple years ago,” Ketzler said. “By burning wood we’ll be saving 10,000 gallons a year, that’s $50,000 to $60,000.”

Most of the wood the city burns in its other buildings is driftwood pulled from the Yukon River. Ketzler estimates buying the extra 80 cords of chipped wood to supply the school’s needs will cost the city around $20,000 per year. Even with the additional cost, the boiler should pay for itself within 6 years at today’s price of $5.50 for a gallon of heating fuel in Tanana.

Promise of a road to Tanana as a part of the governor’s Roads to Resources initiative could provide the city with a long-term supply of biomass fuel. Ketzler said he has been in discussion with the Alaska Department of Transportation and Public Facilities about saving material cleared from the 39-mile long corridor.

“(DOT&PF has) been receptive to the idea – instead of the old traditional way of digging holes and burying all the organics – of looking at how we can save the material that’s three-to-four inches in diameter and stockpile it along the way,” he said.

Officials with the department said they expect construction to begin on the road in early summer 2013. Possible charges to the city for using the wood haven’t been resolved.

Elwood Brehmer can be reached at [email protected].

11/11/2016 - 8:57pm