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Looking for biomass fuel alternatives Could wood and other biomass fuels become a more significant part of the Alaska energy mix, especially for rural communities? Alan Bailey Petroleum News
Thoughts of a bygone era in the Alaska frontier conjure up images of rustic cabins and roaring log fires. And many a home in the state still enjoys the heat from a wood stove. But in the age of central heating and labor-saving appliances, could the humble pile of split logs find a place as a major energy source for the future?
Not quite. But Alaska’s rich endowment of forest could make a larger contribution to the state’s energy supplies, Peter Crimp, alternative energy and energy efficiency program manager for the Alaska Energy Authority, told the Senate Special Committee on Energy Feb. 5. And, to a lesser extent, it is also possible to obtain energy from other biomass sources such as fish oil and domestic waste, he said.
Plenty of wood
Alaska’s 18,000 to 20,000 square miles of forest could deliver more wood than the current estimated 100,000 cords per year burned for heating in the state, Crimp said. On a sustainable basis, Alaska’s forests could supply wood equivalent to 400 million to 500 million gallons of diesel fuel per year, he said. That’s not nearly enough to support the state’s entire energy demand, but could knock an important dent in the use of other fuels.
But wood cutting can conflict with other land uses, Crimp said. And it is important to ensure that there is enough fuel to feed a wood-burning application, taking into account any aesthetic problems involved in cutting the forest. But clearing forest wood can reduce fire risks, enable economic development and enhance habitat, Crimp said.
And it is possible to use fallen timber rather than live trees.
Greg O’Claray, statewide coordinator for Ketchikan-based Alaska Chip Ltd. described how his company supplies firewood for Southeast Alaska from waste lumber gleaned from the forests. O’Claray said that it would be possible to extend his company’s services to western Alaska, to supply fuel for villages there. Alaska Chip is seeking a freight subsidy for barging the wood north, to maintain price parity with firewood in Southeast.
Steven Seley Jr., president of Pacific Log and Lumber, told the committee that it would be possible to supply wood chips or firewood to Nome, for example, at prices equivalent to $1.87 to $2.37 per gallon for fuel oil, including transportation costs.
Smoke Smoke pollution from burning wood is a big concern — wood smoke has become a problem in Fairbanks in Alaska’s Interior. But smoke results from inefficient burning, Crimp said.
A modern wood burning heating system cuts the smoke and maximizes the energy obtained from the fuel. Commercial high-efficiency firewood burning systems are in use in washeterias in Dot Lake near Tok and in the village of Tanana. Systems of that type typically put out about 1 million British thermal units of heat per hour and cost about $250,000, Crimp said.
More advanced systems use wood chips or wood residue from sawmills, rather than firewood. If not burned, the wood residue would end up in a landfill, Crimp said.
AEA and the Denali Commission funded a wood-chip-fired, clean-burning boiler that heats two schools and the community swimming pool in Craig on Prince of Wales Island, Crimp said. The system was commissioned in 2008, he said.
Wood-fired power plants Wood-fired power plants for generating electricity are more complex than simple heating systems. And, although there used to be large wood-fired power plants in Southeast Alaska, there are no longer any in the state. Perhaps there is scope for the use of small power plants to generate electricity for villages that are surrounded by forest, Crimp wondered.
A demonstration project is needed to prove the village-generation concept, he said. A specific power generation application would need a land management plan to ensure a sufficient wood harvest to supply the system and to avoid conflicts with subsistence and other land uses.
There is also a big question regarding how to operate the lumber harvest — mechanized logging would probably be required. Going out with a chain saw is not necessarily the way to supply fuel for a power system, Crimp said.
And, although a small village could likely enjoy a sustainable fuel supply, larger communities like Dillingham, where wood grows fairly slowly, could find sustainability to be challenging.
“That would be a strong feasibility concern,” Crimp said.
Meantime, AEA has been pursuing simple rural heating applications for wood.
“We’ve found that wood-fired space heating of buildings is the low-hanging fruit,” Crimp said. “We’ve been going after that aggressively, working with communities to develop projects.”
Gwen Holdmann, director of the Alaska Center for Energy and Power, told the committee that heating represents a larger energy load than electricity for rural committees. ACEP is a University of Alaska entity that researches and tests technologies that might lower the cost of energy in the state.
“There aren’t many renewables that can really directly address our need for heat, beyond first converting it to electricity,” Holdmann said.
Wood is expensive to handle and has a very low energy density compared with a liquid fuel such as diesel. As a consequence, wood tends to work best as a fuel if it can be sourced near to where it is used, Holdmann said.
Although there are emerging technologies for converting wood into liquid fuels, those technologies are expensive. When it comes to power generation, biomass such as wood can be burned directly or converted to gas through incomplete combustion. However, a big challenge for gas generation is accommodating woods with different moisture contents and from different types of tree, Holdmann said.
Biomass crops There is also interest in growing biomass crops — fast-growing crops such as willow or alder that can be cultivated for power generation. It would typically require about 500 acres of land to sustainably grow one of these crops to fuel a 500-kilowatt generator, Holdmann said. However, there are questions regarding whether the growth rates assumed for these numbers could be achieved in Alaska, she said.
An investigation of the natural growth rates of plants in Interior Alaska indicates that these rates are well below the breakeven rate required for sustainable power generation, she said.
And biomass crop usage would become a means of stabilizing costs rather than reducing costs. Sweden, at a similar latitude to Alaska, has been engaged in willow farming since the 1970s but, despite refinement of the biomass technologies, viable operation depends on support funding.
“It’s expensive and a lot of this wouldn’t be happening without some kind of a subsidy,” Holdmann said.
However, the University of New York has been partnering with some Alaska entities to research the growing of willow and other short rotation crops in Alaska. The researchers’ concept is some form of cogeneration power plant, combining the use of biomass with the use of coal, Holdmann said.
And the University of Alaska has been investigating the use of fast-growing grasses.
One interesting possibility is the use of what is termed an organic Rankine cycle system for small-scale electricity generation, using heat obtained by burning biomass or municipal waste — in a Rankine cycle a fluid with a low boiling point such as refrigerant is boiled to drive a turbine generator. Chena Hot Springs has pioneered the use of a system of this type to generate electricity from relatively low-temperature geothermal water from the springs.
“The opportunity for Alaska is that this represents a high-value niche market for this kind of emerging technology,” Holdmann said. “We really have the opportunity here to take a global leadership role.”
Fish oil In Southwest Alaska we don’t have a lot of trees but we do have a lot of fish, Yvonne Kopy, borough planner for Bristol Bay Borough, told the committee. Bristol Bay Borough is proposing a feasibility study for a processing facility to produce fish oil and other value-added fish products.
Bristol Bay is home to a huge world-class fishery. But a shift in demand in world fish markets from canned fish to fish fillets has increased fish wastage rates in processing facilities to 50 percent, from the rates of 20 to 30 percent involved in canning fish.
“Bristol Bay last year harvested 29 million sockeye salmon. Translated that means over 170 million pounds of sockeyes were harvested,” Kopy said. “Taking just an average of 30 percent waste, that’s 57 million pounds of waste that’s ground up and flushed back into the river system”
Bristol Bay Borough’s proposed facility would convert that waste into energy, rather than throwing it away. The fish waste would not provide enough energy to fuel a complete power plant, but the borough thinks that a power plant would be viable if fish oil is used in combination with other energy sources such as wood, solar or wind.
“With that cogeneration we do believe that it would be possible to operate a fish waste facility 100 percent on renewable clean energy,” Kopy said.
The borough has partnered with the University of Alaska Center for Economic Development and the Institute of Social and Economic Research to research the concept. And it might be possible to apply this type of system elsewhere in Alaska, Kopy said.
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