With biomass, green and not-so-green lines blur

With biomass, green and not-so-green lines blur

May 30 - The Milwaukee Journal Sentinel

How green can the energy produced by a biomass power plant be if it releases carbon dioxide into the air just like a coal or natural gas-fueled plant?

That's the question being raised about biomass projects, including one proposed by We Energies in Rothschild and another Xcel Energy Corp. is considering in Ashland.

"You can't assume that biomass is carbon-neutral. It depends on how many trees you plant and how fast they grow, and all sorts of variables," said Katie Nekola, energy program director at the conservation group Clean Wisconsin. "It's right to look at it case by case to see exactly what the carbon balance is going to be for any plant."

The issue is dividing renewable energy advocates and conservationists in Washington, D.C., as the U.S. Environmental Protection Agency and Congress wrestle with the thorny issue of regulating emissions of carbon dioxide and other greenhouse gases from power plants and factories.

In announcing its plan this month to begin regulating greenhouse gas emissions in 2011, the EPA ruled that it does not consider biomass to be carbon-neutral. At the same time, the agency left the door open to reversing that decision in the future.

In the U.S. Senate, meanwhile, the Obama administration continues to push for passage of climate legislation that would spur development and deployment of renewable fuels and renewable power. The bill passed in the House of Representatives last year but is considered unlikely to pass in the Senate in the face of opposition from Republicans and some Democrats concerned about the cost of the measure.

A group of scientists last week called on Congress to take into account the effect of bioenergy and biofuels on forests, particularly if those forests are harvested entirely for energy and the trees are not replanted.

"Replacement of fossil fuels with bioenergy does not directly stop carbon dioxide emissions from tailpipes or smokestacks," the scientists said in a letter. "Although fossil fuel emissions are reduced or eliminated, the combustion of biomass replaces fossil emissions with its own emissions."

The scientists warned that failing to properly address the effects of bioenergy could undermine the entire goal of a climate-change regulation plan, which is to bring down emissions linked to global warming.

No consensus reached

The issue was debated between the paper industry and other stakeholders who participated in an advisory group for the Environmental Protection Agency, said Mark Thimke, an environmental lawyer with Foley & Lardner in Milwaukee. The advisory group couldn't come to a consensus, he said, and the EPA will end up launching another public-comment process on the issue before it's finished.

"On the one hand, a tree as it grows absorbs carbon, and when burning it you're releasing carbon, and the net effect is you're essentially carbon neutral," Thimke said.

"The other side of the issue is to take a broader look at the indirect effects, including the life-cycle emissions linked to the harvesting equipment and trucking of the biomass from the forest to the power plant," Thimke said. "So there are a number of groups saying there is a carbon effect that has to be quantified, and you should take that into account in the permitting."

Milwaukee-based We Energies is proposing a $255 million, 50-megawatt power plant at the Domtar Corp. paper mill in Rothschild. Some residents in Rothschild, south of Wausau, have objected to the project because of concerns about air pollution that would be released by a new power plant located not far from a $770 million coal-fired power plant in Weston and south of Rothschild.

The utility said it proposed the biomass project as a way to help it comply with Wisconsin's renewable power mandate because it can generate electricity around the clock, unlike a wind farm. The project would supply steam to Domtar's paper mill and create up to 150 jobs, the utility said.

Critics call for a review

Critics of the project are asking the state Public Service Commission and Department of Natural Resources to do a full environmental review of the project.

A detailed review is not required and was not performed for the proposed Xcel Energy biomass plant in Ashland.

The agencies have not decided whether the review, known as an environmental impact statement, will be done for the We Energies project.

"Stop this biomass project now, please," Rebecca Simms of Rothschild said in a public comment filed with the state. "Biomass should no longer be considered an alternative to fossil fuels and should no longer be considered carbon-neutral, because it is not."

In a filing last week in response to an inquiry by state regulators, We Energies disclosed that carbon dioxide, or CO2, emissions from the Rothschild plant would be about 590,000 tons a year.

The utility says that will be offset by the replanting of trees in the forest that will absorb carbon dioxide.

Trees absorb carbon

Because of the commitment by Domtar and We Energies to use sustainable harvesting practices, "it would be considered net-zero because it's all part of the carbon cycle," said Brian Manthey, a utility spokesman.

"When they go out to harvest trees for papermaking, Domtar's suppliers will cut the branches and tops and leave them lying in the forest. That's what we'll be harvesting to use for the biomass," he said. "It's taking materials that would be decaying in the forest and giving off CO2 anyway."

"The carbon is either being absorbed by the trees, or when you do harvest it and you are using that material, that carbon is what will end up becoming CO2. But as you replace those trees that are being harvested for both biomass and paper, you would have other trees that would be absorbing that same CO2," Manthey said.

Supporters of biomass power plants note that these projects would replace generators that burn fossil fuels.

In the case of the We Energies project, the power plant at Domtar would burn less natural gas.

In Madison, the state of Wisconsin has proposed a $250 million biomass and natural gas plant to replace a coal-fired plant that serves the University of Wisconsin-Madison.

In Ashland, Xcel Energy would replace a coal-fired power plant with a biomass gasifier. The status of that project is uncertain, however, after the utility's cost estimate for the project ballooned by nearly 37% to $79.5 million.

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