By Henry Robertson
There are lots of things you can burn to make electricity: coal, gas, oil, trash, old tires — and our forests.
An Indiana company called Liberty Green Renewables and a Houston financial firm, Macquarie Group, have set up a joint venture called LC Biomass Missouri to build a 32 megawatt wood-burning power plant in Perryville. At a public forum on April 7, Perryville residents were treated to a debate between Jack Farley, a partner in Liberty Green, and Dr. Bill Sammons, a Massachusetts pediatrician who’s on a national crusade against biomass burners. Michael Berg, the Missouri Sierra Club’s online organizer, was there.
Farley promised a clean, sustainable operation with state-of-the-art pollution controls that would create 100 construction jobs, 25 permanent jobs, 40 ancillary jobs, new revenue for the forest products industry, property and sales tax revenues, and power for 23,000 homes. It would burn clean wood from the trimming of trees, invasive species and road clearing; limbs and rotten wood; waste from sawmills; and urban wood waste (pallets, discarded furniture, construction and demolition waste).
Dr. Sammons argued that biomass burning is more polluting than coal and is not carbon-neutral on any meaningful time scale. It produces more CO2 than coal per unit of energy because wood is a less concentrated energy source. Though lower in sulfur than coal, it creates more nitrogen oxides and, worst of all, fine particulates, which can burrow deep into the lungs. Air permits, however strict, still allow plants to pollute. The industry is driven by federal subsidies; a tax credit of $10 per megawatt-hour is available for plants that start construction this year and come on line by the end of 2013.
Biomass is generally regarded as a renewable energy source, one answer to global warming. There’s no one silver bullet solution to climate change. Instead there’s “silver buckshot,” and environmentalists find many kinds of renewable energy to support (and oppose — even wind and solar projects).
What I’m concerned with here is “woody biomass,” but the forms of biomass range from algae to corn stalks to pig poop. We want all the solutions we can get, but sometimes I fear we’ve sold our soul by reducing the abundant diversity of nature to a single generic energy resource called biomass.
Is biomass renewable?
An energy source can be renewable because it’s self-renewing like wind and solar or because it is a fuel that we use no faster than it can be replenished, in which case it is carbon-neutral even if burning it releases carbon. The biomass you burn one season grows back the next, absorbing the carbon the first season’s burning released.
Well, that all depends on the rate of harvest. If you feed it a whole tree, a biomass plant can burn in minutes what it will take nature decades or centuries to replace. Forests can be logged sustainably, as Leo Drey has shown with his Pioneer Forest, but you won’t get much electricity that way. And biomass burners only convert 20% of the energy latent in the wood into electricity.
A sustainable fuel supply for a biomass burner would require a large area. One possible alternative is biomass energy plantations of fast-growing willows or poplars. Such plantations will never have the biodiversity or carbon storage capacity of natural forests.
Any way you do it, you’ll have to send trucks to pick up the fuel and deliver it to the plant. The result is more pollution, including CO2, from diesel and gasoline that has to be added to the pollution from the plant itself when the environmental accounting is done. The collection problem also puts a crimp in biomass finances; it just doesn’t pay to gather fuel beyond a radius of 50 miles or so. That’s why biomass power plants are small, rarely more than 50 megawatts compared to hundreds of MW or even several thousand for coal-fired plants.
If they would burn in a year only the tree trimmings or logging debris that grows back in a year, then biomass burners would be carbon-neutral. They’d also be a vanishingly insignificant energy source.
Liberty Green would be competing for wood with “secondary” markets like furniture makers. It has an advantage in the form of the Biomass Crop Assistance Program (BCAP), a federal subsidy for growers and providers of energy crops. Sawmills and lumber yards are getting taxpayer money to supply the likes of Liberty Green. BCAP is driving up the price of lumber nationwide, costing jobs and threatening to drive small forest product companies out of business. Wood chips sell for $28 a ton, says Missouri forest guardian Hank Dorst; with BCAP they can fetch $45 a ton.
Ecology meets economics
Is it worth it? Biomass burning claims to have advantages over old ways of doing business. It creates energy, keeps sawmill waste and urban wood waste out of landfills, and removes forest thinnings that clog up the woods, slowing regeneration and posing a fire hazard.
Dorst estimates the biomass supply available to Liberty Green at one-third sawmill residue, one-third forest residue and one-third urban wood waste. But there’s another game in town, and it might play out differently.
The Missouri Forest Products Association (MFPA) issued a report in January about its “Woody Biomass Technology Demonstration Project.” MFPA plans to build two small (2 MW) pilot plants in Salem and Ava, two of 15 towns that are losing the electricity formerly supplied by Sho-Me Power, a rural electric cooperative.
MFPA sees three feedstocks: small-tree thinning (that’s logging), timber harvest residue (logging debris) and mill residue (sawdust and chips). Urban wood waste doesn’t make the cut, probably because transportation accounts for 60–70% of the delivered price of woody biomass, restricting the supply area to a radius of 25–50 miles.
MFPA envisions this mode of operation: “A biomass harvesting crew of four, operating a feller-buncher, grapple skidder and in-woods chipper…” A feller-buncher is a vehicle that cuts small trees at the base and gathers several of them like a bunch of flowers. A skidder drags trees to a landing to be loaded onto trucks. Roundwood (tree trunks) will be the dominant feedstock, followed by chips hauled out of the woods in chip vans. The “van” pictured in the report looks more like a semi to me.
The report summarizes the results of a survey by MFPA of small logging companies in the region. Most of them are interested in the opportunity, but they’d prefer taking out roundwood instead of chips because in-woods chipping equipment requires a bigger investment.
As for the timber residue the biomass boosters promise to clean up, the MFPA records this telling comment from the survey: “Logging debris from past timber sales is probably not economically recoverable.”
In short, they’ll be cutting trees.
Biomass and Prop C
Liberty Green’s Farley told the Perryville audience that the plant will make renewable energy to comply with Proposition C, the Renewable Energy Standard passed by Missouri’s voters in 2008. Prop C requires the three investor-owned utilities, AmerenUE, Kansas City Power & Light, and Empire District Electric, to use renewable electricity to make up 2% of their sales by next year and 15% by 2021. If Liberty Green’s plant were certified as a renewable energy facility by the Department of Natural Resources, it could sell “renewable energy credits” to the utilities that they could use to comply with Prop C. Each credit represents one megawatt-hour of renewably generated electricity.
Prop C counts “dedicated crops grown for energy production…plant residues” and “clean and untreated wood such as pallets” as renewable energy sources. However, it also says, “Renewable energy facilities shall not cause undue adverse air, water, or land use impacts, including impacts associated with the gathering of generation feedstocks.” That gives DNR the power to deny any facility certification as a renewable energy project, or even to ban an entire technology, if it causes unsustainable logging or excessive pollution.
Greenwashing — the claim that some technology or business practice is “green” even though it isn’t — is a hazard we must constantly be on the alert for. It looks like that’s what we have in the case of biomass combustion for electricity. It isn’t green, renewable or sustainable. At the Perryville debate Farley even conceded Dr. Sammons’s point that it isn’t carbon-neutral. I guess he doesn’t get what sustainability is all about.