Speaking of smoke: Oregon’s only coal power plant may convert to biomass, but plan has many unknowns

Michael Giberson

The High Country News reports that Portland General Electric is considering shutting down its Boardman, OR, coal-fired power plant, with costs of Clean Air Act compliance cited as the cause.  However, another option under consideration is conversion of the plant to biomass, more specifically converted to use a torrefied Asian cane that would be grown specifically to fuel the plant.

But it’ll take years of study to determine if that would work, plus at least $600 million to convert the plant, install additional pollution controls, and build a torrefaction facility. To reduce transport costs, PGE also would need to grow as much as 100,000 acres’ worth of cane on arable land within 50 miles of the plant. “It’s a giant experiment,” says Jaisen Mody, PGE’s general manager of generation projects, “with a lot of challenges.”

Logistical and financial challenges have long plagued biomass power plants, regardless of fuel source. The industry peaked in the mid-’90s; since then, it’s been hampered by supply difficulties, deregulation and the relatively low cost of fossil fuels. This summer, plans for a $500 million, 107-megawatt hybrid solar thermal and biomass plant in Fresno County, Calif., were scrapped; developers blamed project economics and an inadequate local biomass supply. An $8 million plant built in 2007 to power a Nevada prison with forest waste was shut down in September, after running into wood-supply problems and local clean-air standards more stringent than the federal government’s. Still, “if the world puts a price on carbon,” says Lee Rybeck Lynd, biomass expert and professor of engineering at Dartmouth College, “we’ll see better economics and greater activity in biomass.”

That raises a more fundamental question: Just how green is biomass?

The article continues with a discussion of the “how green is biomass” question. Worth contemplation if you are interested in renewable power.

An assessment of “The Environmental Impact of Biofuels,” to be published in the Annual Review of Ecology, Evolution, and Systematics concluded:

Biofuels are the most land-intensive form of energy production. The land requirements for biofuels have potential negative consequences for biodiversity and GHG emissions by causing, either directly or indirectly, the conversion of natural ecosystems to cropland. Although the magnitudes of these effects are poorly constrained, we can identify strategies to mitigate these effects. Development that follows the mitigation hierarchy can dramatically improve outcomes for biodiversity. The mitigation hierarchy follows these steps for development: (a) avoid sensitive areas, (b) minimize impacts through best practices, (c) restore areas after use, and (d ) fund compensatory offsite mitigation. In the case of conversion to biofuel crops, avoiding sensitive areas is perhaps the most important and complex of these steps. [Citations omitted.]

Since the PG&E proposal would convert existing crop land (given the area, wheat is likely the displaced crop) to biomass plants, it avoids direct conversion of undeveloped lands to agricultural use. On the other hand, unless abandoned or marginal crop land it used then at the margin either some other farm land must be added to replace the lost production or food costs will rise.


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