Forest biomass could power fuel cells
Energy researchers at Humboldt State University, in California’s North Coast redwood country, describe their county as an "energy island."
Its four connection points to the outside electrical grid provide just around 70 megawatts of transmission capacity, well under Humboldt’s peak demand of 170 MW.
One result of that circumstance is that biomass, in the form of timber byproducts, has long been a big part of the county’s energy picture. It’s not always the most efficient way to make power, however — but there’s a project unfolding that’s promising to vastly improve the process.
Traditionally, wood products have been used in to fire steam electric plants. Now the Blue Lake Rancheria Tribe is aiming to use biomass to produce hydrogen, which will then be used in a 175-kilowatt fuel cell system from Ballard Power Systems. According to Ballard:
"The system will convert locally-grown timber by-product feedstock into hydrogen-rich syngas, using pyrolysis gasification technology. This syngas will then be purified, resulting in a high quality hydrogen stream, which will be used to power the ClearGen fuel cell system."
If you’re wondering what this thing called “pyrolosis” is, here’s the nutshell explanation from the U.S. Department of Energy’s Fuel Cell Technologies Office:
"Pyrolysis is the gasification of biomass in the absence of oxygen. In general, biomass does not gasify as easily as coal, and it produces other hydrocarbon compounds in the gas mixture exiting the gasifier; this is especially true when no oxygen is used.
"As a result, typically, an extra step must be taken to reform these hydrocarbons with a catalyst to yield a clean syngas mixture of hydrogen, carbon monoxide, and carbon dioxide. Then, just as in the gasification process for hydrogen production, a shift reaction step (with steam) converts the carbon monoxide to carbon dioxide. The hydrogen produced is then separated and purified."
This might sound like a pretty complicated way to make electricity, but Ballard says there’s a payoff: Going this route could double the efficiency of biomass-to-power generation.
“Using biomass to produce hydrogen is an important enabler for distributed generation applications,” Larry Stapleton, vice president of sales for Ballard said in a statement. “This initial installation will demonstrate a renewable, high efficiency, low emission solution that is cost competitive today in communities relying on diesel generators.”
Participants in the Blue Lake Rancheria Tribe project include the Redwood Coast Energy Authority and the Schatz Energy Research Center, which were collaborators last year on a report [PDF] mapping out energy strategies for Humboldt County in the next 20 years.
Biomass, already a supplier of around a quarter of the county’s electricity, was pegged as an even more significant source. Bio-anything energy is always open to scrutiny because it can often have adverse impacts, but Humboldt at least is saying the right things when it comes to promoting biomass. According to the report :
"Substantial biomass resources go to waste every year (i.e., logging slash and material from thinning and fuel reduction treatments) in remote areas where it is not currently cost-effective to process and transport the biomass for energy or other purposes. The community should support an assessment of resource sustainability and a life cycle analysis of greenhouse gas emissions to confirm the viability of this resource.
"Biomass energy plans that are consistent with forest restoration needs and priorities should be developed, and technologies and processes that can potentially expand the range of sustainable biomass to energy opportunities should be researched and developed."