Is biomass energy still renewable? Some scientists say no.

Posted on: Jun 28, 2016 - 11:55 AM | General

A crew from Hemmerich's Tree Service feeds low grade trees into a wood chipper to deliver wood chips to ReEnergy Holdings' biomass plant in Lyonsdale, NY. This kind of logging operation is at the heart of a debate over biomass as a renewable energy source.

Once a booming industry, biomass, producing electricity by burning trees or other organic matter, is getting hammered by low electricity prices and growing questions over whether it is renewable after all.

According to U.S. energy data, biomass produces more renewable energy in the United States than solar panels, comprising 1.6 percent of nationwide electricity production compared to 0.6 percent for solar. But the biomass industry is shrinking these days, not growing. A couple months ago, ReEnergy Holdings' biomass plant in Lyonsdale, NY, went offline, in large part due to low electricity prices.

But the company was also concerned about its product's standing as a renewable energy source. According to state data, New York paid biomass producers $52 million in renewable energy incentives since 2004. But now, New York is writing a new renewable energy plan, and nationwide, there’s a growing debate over whether biomass deserves that “green” label. Much of that debate revolves around logging practices for the wood that fires biomass plants.

Biomass gives loggers an extra product

I went to the edge of the massive Tug Hill Plateau forest to learn more about how biomass fuel is harvested. I met Greg Hemmerich, owner of Hemmerich's Tree Service in Lowville. He had three piles of logs in a pasture he was clearing for a dairy farm in Lowville. The first was a small pile of cleanly cut and trimmed tree trunks. Those are for furniture, veneer, and other higher quality products, said Hemmerich. Next to that, the second pile was slightly bigger. Those logs will be split into firewood for homes.
Then we turned to a huge gnarly pile that dwarfed the other two. Snarls of evergreen trees, needles and all, are clumsily piled in a heap. "There’s a lot of balsam, lot of spruce, thorn apple trees," said Hemmerich. "Ninety percent of this lot is low-grade wood." This third pile was destined for the biomass plant. If it weren’t for biomass, Hemmerich said, it wouldn’t be worth clearing this pasture to begin with.

Biomass and "carbon neutrality"

What makes these low grade trees valuable is that they grow back, and this is why biomass is considered renewable. When you cut down and burn a tree, it releases carbon gas, which causes climate change. But if you plant a new tree in the old one’s place, it’ll grow and suck up that carbon. In other words, it’s carbon neutral, said David Murphy, an assistant professor of environmental studies at St. Lawrence University who studies renewable energy. "So it’s not adding any greenhouse gas emissions over the whole life cycle of that species, of that plant.
Based on that idea, 37 states, including New York, and the federal government, have included biomass in their renewable energy plans. Biomass plants get paid a bonus because they help reduce climate change emissions. And that’s been key to the industry’s growth.

But some scientists and environmental groups are now challenging the “renewability” of biomass. John Coequyt, director of Federal and International Climate Campaigns for the Sierra Club, said part of the environmental community is cooling off on biomass. "It’s absolutely true that we’re becoming, as a whole, a lot more skeptical of biomass’ ability to deliver large amounts of electricity in a sustainable fashion."

How do you define sustainable logging?

The debate centers around how you define sustainable logging. According to some green groups, demand for biomass fuel drives a risk of deforestation, especially in the Southeast, where loggers supply a booming wood pellet market in Europe.

But the industry  and many forestry experts insist biomass burns mainly forest and farm leftovers, "everything from orchard prunings and rice hulls to tops and limbs from forestry operations, bark, and sawdust," said Bob Cleaves of the Biomass Power Association. He said biomass plants don’t have economic incentive to burn anything but low-value material. "There’s no question that it would be a very different calculation if you were to take mature trees and you were to cause deforestation or land use changes, but that’s not happening in the power sector today."
But critics tell a very different story. "What’s actually happening is we are cutting down perfectly healthy, productive trees," argued Tim Searchinger, a research scholar at Princeton University. He said sure, if logging scraps are sitting on the forest floor, send them to the biomass plant. But taking an example like Greg Hemmerich's pasture clearing in Lewis County, he said even those low-value trees suck up carbon dioxide, and they shouldn't be cut down. He said we need to reduce the effects of climate change now, but it takes decades to replenish those trees burned in the biomass plant. "That takes a long time. And in the interim, you’ve actually probably increased the amount of carbon in the atmosphere."

Searchinger is among 65 scientists fighting an amendment in the new energy bill in Congress. It calls biomass by definition “carbon neutral.” The scientists say it’s more nuanced than that; the devil’s in the details of each logging operation in the woods.

A recent study [see p.114-120] by New York State argued for similar caution, saying overall carbon emissions of biomass fuels "are highly dependent on site specific factors. Some biomass fuels are more carbon intensive than others," it warned, and concluded that "a robust accounting" of lifetime carbon emissions is necessary. Cleaves of the BPA said that's already happening in New York and elsewhere.

"There's no free lunch" for energy

St. Lawrence University’s David Murphy said, "At the end of the day, one thing we need to remember is that there’s no free lunch." He said our electricity has to come from somewhere, and a lot more of it needs to come from sources that limit the gases that cause climate change. "If we’re doing it from biomass, maybe that’s offsetting natural gas," said Murphy, adding that more heavily managed forests may be a side effect. "But that’s a trade-off that is being made, either way," he said. "So we have to decide either locally, or as a state, or nationally, where we’re going to get our energy resources from, and where we’re going to put the costs. Because the costs exist."

Murphy said that’s why strategic energy plans are so important. New York is in the final stages of drafting its new plan for getting 50 percent of the state’s electricity from renewables by 2030. And so far, biomass is one of those renewables.That’s good news for loggers in the North Country woods and the biomass plants in Lewis and Jefferson counties.

Source: ncpr


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