Wood is plentiful in New England, but as a fuel it is mucking up efforts to address climate change here and around the world.

A recent expose by the news website Climate Central highlights the failure of policymakers to account for wood-burning power plants when considering greenhouse gas emissions. The report focuses on the loophole in European Union climate policy that allows woody biomass to be considered a renewable energy despite emitting more carbon dioxide pound for pound than coal.

Here in southern New England the biomass renewable exemption also exists. In the mandated allocation of renewable energy that flows to everyone’s electric sockets — called the renewable portfolio standard, or RPS — there is plenty of wood-generated electricity and little evidence that the carbon dioxide it’s generating is being neutralized.

Most of the biomass electricity used in southern New England is imported from wood-burning power plants in New Hampshire and Maine. And although the power plants may burn wood sourced from scrap and sustainably managed forests, they still release carbon dioxide that requires decades or longer to neutralize, according to a number of researchers and scientists.

In 2013, the most recent year reported, Massachusetts tallied 8 percent of its renewable energy portfolio from wood-powered biomass. That’s down from a high of nearly 49 percent in 2007. Massachusetts reduced its woody biomass use as some older power plants phased out or ceased production. The state also enacted new regulations in 2012 that only allows biomass power plants to be considered renewable if they follow new standards, such as sourcing wood from byproducts from lumber mills and forestry residue, and if they don’t displace virgin forest. Massachusetts is the only state that mandates that the plants also provide heat.

Rhode Island and Connecticut, however, rely much more on wood-burning plants for their RPS and with less rigorous standards than Massachusetts. In 2013, Rhode Island received 51 percent of its RPS from biomass, also imported from wood-burning power plants in New Hampshire and Maine. Connecticut received 60 percent to 80 percent of its RPS from biomass wood between 2009 and 2011.

“Connecticut’s RPS is dirty, really dirty,” said Mary Booth of the Partnership for Public Integrity (PFPI). “It’s in the worst in New England.”

Booth has been raising awareness about the pollution caused by biomass plants since 2009 and was part of the effort to tighten regulations in Massachusetts three years ago.

Some wood power plants release more pollutants than others, especially those that burn construction and demolition debris. But all release greenhouse gases.

“There’s no getting around the fact that if you are burning biomass you are emitting more carbon than you were before,” Booth said.

To compound the problem, the seven-state Regional Greenhouse Gas Initiative (RGGI), which taxes power plants for carbon emissions, exempts biomass plants from paying for their greenhouse gas emissions. In fact, carbon dioxide emissions emitted from woody biomass plants are deducted from a state’s total annual emission count.

Frank Stevenson, Rhode Island’s RGGI representative, explained the dilemma with wood-fueled power. “It is renewable,” he said. “But the sustainability is the question.”

Carbon-neutral assumption
Conventional wisdom once dictated that wood energy plants were carbon neutral as long as the trees used for fuel were replaced. But a 2010 report done for Massachusetts by the Manomet Center for Conservation Sciences showed that it takes decades, if not a full century, for a well-managed wood source to start offsetting the carbon emitted through burning.

At a time when scientists say heat-trapping emissions must be cut drastically to prevent irreversible global warming, wood power looks more like an impediment than a tool for reducing greenhouse-gas emissions.

Although Massachusetts regulations are more stringent than most states, they still require that carbon dioxide emissions from woody biomass be offset within 20 years.

“If you are concerned about crossing a climate tipping point, which some scientists say could occur in the next decade, then anything that increases greenhouse gases in the atmosphere in the next 10 years is a bad choice for you,” Manomet’s president, John Hagan, wrote in a 2012 article.

The Manomet report was a first of its kind in the United States and launched subsequent studies that reached similar conclusions about woody biomass power. The original study found that wood releases a pulse or high concentration on carbon dioxide when burned. It concluded that forests grown to replace burned wood can takes decades to keep pace with emissions. When fueling power plants, more wood is required to equal the energy delivered from coal, oil and natural gas. Once wood equals that energy, it releases 50 percent more carbon dioxide than coal and 300 percent more than natural gas.

“Very simply, the assumption of carbon neutrality for biomass emissions is no longer credible,” PFPI’s Booth wrote back in 2010.

The Boston-based Conservation Law Foundation (CLF), which crafted Massachusetts woody biomass regulations, is cautious of biomass power, saying that “careful siting, design and fuel sourcing are required to protect forests and other sources of fuel, limit emissions of pollutants, conserve water used for cooling, and ensure that biomass is used efficiently so as not to waste a limited resource.”

When asked if wood power should be allowed to meet state RPS goals, Jerry Elmer, a senior attorney with CLF, said, “That is a very valid concern.”

Nevertheless, many states, and countries, are moving forward with wood-fired biomass power plants. A $150 million project proposed for East Springfield, Mass., recently cleared its final legal challenge. In 2014, the 37.5-megawatt Plainfield Renewable Energy Plant in eastern Connecticut went online. The biomass plant burns sorted construction and demolition debris, wood pallets and forestry byproducts, and releases an estimated 449,207 tons of carbon dioxide annually.

Meanwhile, Europe is using big subsidies to convert coal plants to wood, to meet its RPS goals. There is no accounting done by EU climate leaders for wood’s carbon dioxide output simply because it’s classified as a renewable resource. As demand grows by an estimated 20 percent annually, other CO2 emission contributors are ignored, such as the transportation and manufacturing of wood pellets, the preferred form of wood fuel for biomass power plants outside the United States.

Japan, Korea and Australia also are converting coal plants to wood, or building new wood-fueled biomass plants. There also is concern that China will make a similar large-scale conversion to wood-fired power plants. All of which will stress forested regions and increase carbon emissions.

Some experts believe wood fuel can be done sustainably, mostly by using wood byproducts and natural debris. Groups such as the Rocky Mountain Institute and Union of Concerned Scientists say biomass can account for some 20 percent of domestic energy.

The Environmental Protection Agency (EPA) allows woody biomass in new federal Clean Power Plan, but only plants built after 2012 will be eligible. Each state must set the pollution rules for these new plants, while the EPA can veto those rules.

However, as demand in the United States and abroad for wood fuel grows, there is fear that healthy, hardwood forests will be threatened, much as they are in the southeastern United States. This region feeds more than half of Europe’s new demand for biomass energy with wood pellets.

Manufacturing wood pellets requires energy, as does shipping them overseas. Neither of these ancillary sources of emissions are included in carbon calculations here or abroad.

Because of their high price, wood pellets aren’t burned in the 80 or so U.S. biomass plants. New England has eight pellet manufacturers and so far locally made pellets serve the domestic pellet stove market. Pellet makers in the Southeast are shipping overseas, and Maine is considering an export terminal. The industry also is experiencing rapid growth across the country and putting pressure on local forest habitats.

Some environmentalists believe forests are simply too valuable to be used as fuel, saying they should be left alone to help control atmospheric carbon dioxide levels. Even residue wood should stay in the environment so that carbon dioxide releases slowly and the decomposed wood enhances and protects soil, they say.

“We now know that burning trees to produce electricity actually increases carbon pollution, meaning it has an even worse impact on climate change than coal and other fossil fuels. And it destroys ecosystems that can never be replaced,” according the National Resources Defense Council.

The recent Climate Central article seeks to draw attention to these issues ahead of the global climate summit in Paris that starts Nov. 30.