Cleaner Than Coal? Wood Power Makes a Comeback

Converting from power plants from coal- to wood-fired may not deliver environmental benefits as advertised

In the midst of black spruce and jack pine stands in northwestern Ontario’s Crown forests, a global trend has come home to roost. Atikokan Generating Station ceased burning coal last year to prepare for its new fuel: locally sourced wood pellets.

Canada already sends wood pellets abroad for power generation, but it is now leveraging the resource on a large scale in its own backyard. Atikokan will be the largest commercial power plant in North America to convert from coal to biomass, a trend that has caught on worldwide, especially in Europe.

The retrofit is part of Ontario’s plan to be the first jurisdiction in North America to shut down its coal fleet. In Europe the drive to retrofit coal-fired power plants to biomass comes from the European Union Renewable Energy Directive, which calls for 20 percent of energy to come from renewables, including biomass, by 2020. Much of Europe’s wood pellets are being imported from private forests in the southeastern U.S. as well other parts of North America.

The move away from dirty coal to a renewable resource is seen as a win in terms of carbon emissions by some governments, but not everyone agrees. The definition of sustainably harvested wood pellets varies by power plant and country, and some environmentalists fear that the growing need for biomass will outstrip any benefits from sidelining coal. “If we’re going to have this global trade in wood energy,” says Brian Kittler, project director at the Pinchot Institute for Conservation, “we have to ask, how well do the European and U.S. systems match up?’”

Studies have found that burning wood over fossil fuels produces about 65 to 95 percent less greenhouse gas emissions. Those studies, however, do not take into account the change in forest carbon stocks, according to Thomas Buchholz, a senior scientist at Spatial Informatics Group who studies greenhouse gas emissions related to bioenergy systems. When researchers start adding in the change to the forest carbon stock, the picture changes, which worries environmentalists. Although trees can be replanted, whereas coal is a finite resource in the short term, there is debate as to how much carbon smaller trees take up compared with mature trees. Based on a study Buchholz did for the Southern Environmental Law Center, if Europe imports southeastern U.S. wood instead of burning coal, atmospheric greenhouse gases could up to a 300 percent in the first 50 years, although they would drop below fossil fuel levels eventually.

In the U.K. Drax Power Station is spending $1.1 billion to convert half of its 4,000-megawatt coal-fired facility to wood pellets, much of which will be imported from North America. Although Drax has drafted sustainability guidelines, environmentalists question whether the world’s largest biomass power station will be able to sustain itself on wood pellets made from just logging residue. The European Union has delayed its final decision on wood pellet sourcing criteria several times.

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