Coal Plants Turn to Biomass: Does That Make Sense?

As coal gets edged out by natural gas and regulations that require cleaner power plants, the industry is looking for a new lease on life – they figure their plants will be cleaner if they co-fire with biomass.

That biomass mostly comes from wood chips, and many aren’t convinced that’s a good idea.

For now, state regulators typically approve these plants, such as one that Dominion Resources opened last year. The $1.8 billion facility co-fires coal and waste wood, generating 585 megawatts. "The use of low-cost waste coal and biomass will result in the unit having favorable economics, bringing savings to customers," David Christian, CEO of Dominion told Forbes. 

By the end of this year, Dominion will have converted its last three Virginia coal plants to also run on waste wood.

In fact, at least 20 utilities in North America now use wood chips to replace 5-25% of coal or natural gas, says Forbes. Biomass is becoming a key energy source with 7,000 MW installed and co-firing with fossil fuels is an immediate way for utilities to cut carbon dioxide emissions, says the Department of Energy.

And some are building plants that run solely on biomass, like Southern Company’s 100 MW plant in Austin, Texas. It takes twice the biomass to produce the energy of coal, leading groups like the Manomet Center for Conservation Sciences to conclude their emissions are even higher.

Then there’s the source of wood chips – are they truly "waste," like debris from superstorm Sandy, or are trees being cut for this purpose?

There’s no climate benefit to using biomass if trees are being cut and in fact that would increase carbon emissions. 

Suggestions that a forest biofuel industry would be greenhouse "neutral" or even reduce greenhouse emissions "are based on erroneous assumptions," say scientists from several countries in the journal Global Change Biology/Bioenergy.

If this industry were to grow significantly, there would be younger forests (young trees absorb much less carbon than older trees), depleted soils, increased risk of erosion, loss of forest biodiversity and function, and increased use of fertilizers – another source of greenhouse emissions.

"Society should fully quantify direct and indirect greenhouse gas emissions associated with energy alternatives, and associated consequences, prior to making policy commitments that have long-term effects on global forests," the scientists write. "There is substantial risk of sacrificing forest integrity and sustainability with no guarantee to mitigate climate change."