Biomass as an alternative to coal

The term biomass generally includes any organic material that is not a fossil fuel. The National Renewable Energy Laboratory (NREL) defines biomass as "any plant-derived organic matter. Biomass available for energy includes herbaceous and woody energy crops, agricultural food and feed crops, agricultural crop wastes and residues, wood wastes and residues, aquatic plants, and other waste materials including some municipal wastes."

Environmental impacts

General

The majority of conversion projects to date are centered on switching to biomass fuel sources. Biomass generally includes any organic material that is not a fossil fuel. The National Renewable Energy Laboratory (NREL) defines biomass as "any plant-derived organic matter. Biomass available for energy on a sustainable basis includes herbaceous and woody energy crops, agricultural food and feed crops, agricultural crop wastes and residues, wood wastes and residues, aquatic plants, and other waste materials including some municipal wastes."

Support for biomass within the environmental community is mixed, and there are no easy generalizations about its environmental pluses and minuses. Ultimately, critics argue that the environmental impacts of biomass are not well enough understood to justify moving forward with large-scale projects, and that in fact there may be disastrous implications for any significant reliance on biomass power generation. The Southern Environmental Law Center says that biomass holds some promise for improving the environment if safeguards and clear definitions of what constitutes a renewable energy source are put in place. Otherwise, the SELC said, "the use of biomass could backfire, turning mature forests into energy plantations, harming our water and wildlife, and increasing global warming emissions."

Increasing biomass production in the Southeastern US is a response to demand from converting coal-fired units in the European Union. Demand for wood pellets in the EU will rise to 20-50 million tons by 2030, up from the current 10 million tons per year, according to some estimates.

Carbon neutrality

Biomass materials are often described as "carbon-neutral," because they release the same amount of carbon when burned as they remove from the atmosphere while growing. In theory, the CO₂ released during the combustion of biomass materials will be recaptured by the growth of these same materials, creating what is described as a "closed-carbon cycle". Fossil fuels, by contrast, emit vast quantities of carbon dioxide that were captured through photosynthesis millions of years ago and would otherwise remain trapped underground.

However, many environmentalists are firmly against the use of biomass to offset coal-generated power. Critics point out that no combustion technologies actually mitigate greenhouse gas emissions, and that the focus of a new energy policy should be on energy conservation and zero-emissions technologies like wind and solar. Further, while biomass technologies may be touted as carbon-neutral, in practice this may not be the case. Studies suggest that in reality, the carbon released by burning would take decades to remove from the atmosphere, because of the length of time necessary to replenish harvested tree and plant material and re-sequester the equivalent amount of CO₂.

In 2009 the state of Massachusetts suspended licenses for new wood-burning power plants and commissioned a study on the environmental impacts of burning wood for electricity. That 2010 study, “Biomass Sustainability and Carbon Policy Study”, conducted by the Manomet Center for Conservation Sciences, found that, per unit, wood releases more climate-damaging gases than coal, emitting more heat-trapping carbon dioxide into the atmosphere per unit of energy than oil, coal, or natural gas. Further, that increase in greenhouse gases can take longer for forests to absorb than previously thought: a generation or more in many cases. If a wood-burning power plant replaces a coal-fired one, it can take about 20 years before any net benefits are realized, and more than 90 years if a wood-burning plant replaces a natural gas plant. Ian Bowles, the Massachusetts Secretary of Energy and Environmental Affairs, told the Boston Globe that the findings have broad implications for clean energy and the environment in Massachusetts and beyond.

Some say the Manomet study's conclusions were not cut and dried. "Over time, using wood for energy can lead to lower atmospheric greenhouse gas levels," said Tom Zeller of the New York Times. "While emissions from burning wood are initially higher than from fossil fuels, regrowing forests sequesters carbon, a process that eventually can yield greenhouse gas levels lower than would have resulted from continued burning of fossil fuels. The key issue, and the focus of the Manomet study, is the timing and magnitude of these effects."

Emissions and health impacts

Supporters identify biomass as an improvement over coal, touting benefits that include significant reductions in the emissions of sulfur dioxide, nitrogen oxides, and mercury.

Biomass releases approximately the same amount of particulate matter as coal and fifty percent more carbon monoxide and carbon dioxide. A Massachusetts study found that 135MW of biomass energy generation would produce 482 tons of nitrogen oxides, 617 tons of carbon monoxide, 165 tons of particulate matter, and 2.2 million tons of CO₂.

According to Biofuels Watch and the American Lung Association of New England, the majority of biomass power plants emit toxic air pollution, depending on air pollution controls at the facility, that cause asthma, heart disease, respiratory failure, and create other medical complications. For the smokestack emissions that matter most to climate change and public health – carbon dioxide, NOx and particulates, per unit of power produced, biomass burning is said to be worse than coal. Additionally these plants emit the most harmful toxins known to man, both dioxin and mercury. Particulate emissions are of grave concern as they are worse than those from coal plants per megawatt of electricity produced. The American Lung Association of New England has stated “Burning biomass could lead to significant increases in emissions of nitrogen oxides, particulate matter and sulfur dioxide and have severe impacts on the health of children, older adults, and people with lung disease.” In 2009 the Association urged Congress to exclude biomass burning from the federal climate legislation.

The Massachusetts Medical Society (representing 22,000 doctors and publisher of the New England Journal of Medicine) is on record opposing biomass energy plants as an "unacceptable risk to the public's health by increasing air pollution."

The American Lung Association says that burning wood in a modern and well-maintained woodchip boiler produces more particulate matter than burning fossil fuel, but less SO2 than oil or propane.

Biodiversity

The cultivation and clearcutting of biomass materials on a large scale also bear major implications for wildlife habitats, biodiversity, water supplies, as well as a potential depletion in the terrestrial carbon sink. Ecologists point out that even using waste wood or so-called marginal lands would still disrupt natural habitats. For biomass to be an effective energy source on a large scale, it would have the potential to "decimate biodiversity in an attempt to save the planet," according to ecologist Mike Palmer of Oklahoma State University.

Economics

A study reported in the Journal of Environmental Science and Technology found that co-firing biomass with coal can produce cost-competitive, emission-reduced electricity even without the advent of a cap-and-trade system. Yet several planned conversions of coal to biomass have been suspended or put on hold for economic reasons.

Biomass Conversion Projects

There is a growing trend in the utility industry to convert existing coal-fired power plants to burn what are, by some, considered to be more environmentally-friendly fuel types, such as biomass and natural gas, though whether such conversions are environmentally beneficially remains controversial. This trend is driven by a number of factors, including state-level renewable portfolio standards; federal incentives and looming environmental regulations; consumer demand and environmental awareness; and an economic climate that is making coal less attractive. Although conversion costs can be expensive, utilities already have the facilities sited and water supply and transmission lines established. Converting existing facilities can often cost less than installing the emissions control systems required to keep an antiquated coal plant running.

California

• Mt. Poso Cogeneration Plant was in the process of conversion from coal and tires to 100% biomass in the form of agricultural and residential green waste from nearby areas in 2010 in order to comply with California policy initiatives requiring Investor Owned Utilities to achieve 20% of power needs from renewable energy sources by 2010.
• Port of Stockton District Energy Facilityis scheduled to switch to biomass in 2013.

Colorado

• Valmont Station: Boulder, CO -- Xcel and the City of Boulder are in negotiations to renew Valmont Station's contract with the city. The agreement must be renewed every five years and is slated to expire in August 2010. Many Boulder residents are pushing for the plant to stop burning coal and either shut down entirely or convert to biomass fuels, such as beetle-killed timber, forest slash, and invasive shrubs. On July 14, 2009, the Colorado Air Quality Control Commission held a hearing to solicit public comment on renewing the plant's permit. More than 200 people attended a rally before the meeting to oppose allowing the plant's continued use of coal. About 50 people addressed the Commission, asking its members to deny the permit because the plant emits more than 1 million metric tons of carbon dioxide each year.

Georgia

• University of Georgia Physical Plant Possible Conversion to Biomass. In March 2010 school director Ken Crowe stated that biomass may be in the coal plant's future. "There is a lot of discussion about what we will do with the coal plant over the next 10 years,” Crowe said. “We have had at least one major study that basically asked the question, if we were going to replace it with something that was a more renewable fuel source, what are the most likely alternatives? “I’m totally supportive of moving toward a wood-based fuel if it can be proven to be a reliable source of fuel, a cost-effective source of fuel, and if it can integrate reasonably into our existing system here."

• Mitchell Steam Generating Plant: Albany, Georgia. On March 19, 2009, the Georgia Public Service Commission approved a request from Southern Company subsidiary Georgia Power to convert the coal-fired Mitchell Steam Generating Plant to burn surplus wood waste. When the transition is completed, Mitchell will be the first biomass plant in Southern Company's fleet and "the largest biomass facility in the United States" at 96 MW, according to COO Tom Fanning.

Hawaii

• Hu Honua Station: Big Island, Hawaii -- In August 2008, the Hu Honua Bioenergy facility opened on the Big Island of of Hawaii. The 24 MW plant was previously coal fired, but now burns locally-grown sustainable crops and plant waste that would otherwise be sent to landfills. The plant supplies about 7-10 percent of the island's power, or enough for about 18,000 homes. According to the developers of the plant, the conversion will help Hawaii meet its goal of having 20 percent of its energy production come from renewable resources by 2020.

Illinois

• The Eastern Illinois University Power Plant is a coal-fired plant built in 1925. In 2009 the University submitted permits for a new biomass facility to replace the coal plant, including possible wind turbines. The new plant will be a “biomass gasifier” that will fill University heating and cooling needs by burning nontreated wood chips obtained as lumber industry by-products. The proposal is the largest project in campus history in terms of the dollar amount.
• Pearl Station, Pearl IL -- In 2010, Prairie Power Inc. received a construction permit to install and operate equipment to prepare greater amounts of biomass fuels, and began burning 10% biofuels in the plant. PPI said it is waiting for impending EPA regulations to determine if full biomass conversion is more economic than burning coal.

Indiana

• Jasper 2 Power Plant: Jasper, IN. In July 2009, the Jasper Municipal Electric Utility announced it was considering converting its coal-fired power plant to burn waste wood. The 15MW plant has been shut down for all but a few weeks this year, because it has become too expensive to operate. A conversion project would cost an estimated $11 million, but the city could see a profit of about $1 million each year.
• Liberty Green Renewables -- A 32 MW biomass plant planned for Milltown, IN and proposed in July 2009 by Liberty Green Renewables failed to secure zoning and water permits. The incinerator would have cost about $90 million, and was planned to be running by 2011. The plant was successfully opposed by two Indiana citizen/environmental groups: Citizens Action Coalition of Indiana and Concerned Citizens of Scott County, who worry about the emissions and that that the plant will promote the further cutting down of local trees by forest industries for the wood byproducts. Liberty is also looking into constructing other biomass plants in the state, and wants to build six other biomass plants in five other states.Following the denial of permits, Liberty Green asked the Indiana Utility Regulatory Commission to exempt it from state regulatory law, but the case was dismissed July 16, 2011.

Iowa

• University of Iowa Power Plant Considers Conversion to Biomass -- School administrators announced during a meeting where students voiced their opposition to coal, that the University of Iowa was considering the use of biomass as a transitional fuel to reduce the amount of coal burned at the school. However, they did not know the cost of the time frame for such a conversion.

Louisiana

• Big Cajun II Power Plant: New Roads, LA -- In September 2009, NRG Energy announced it was replacing some coal at Big Cajun II with switchgrass and sorgham. The company said the project could eventually lead to commercial-scale biomass fuel projects as a means of dealing with potential greenhouse gas regulations.

New Hampshire

• Schiller Station: Portsmouth, New Hampshire -- In October 2003, the Public Service Company of New Hampshire (PSCNH) filed a plan to convert Unit 5 of the coal-fired Schiller Station to burn woody biomass. The $75 million dollar project broke ground in December 2004 and went online in December 2006. The unit burns 400,000 to 450,000 tons of wood per year to power approximately 50,000 homes. Using biomass in this unit reduces coal use at the plant by over 30 percent, or about 130,000 tons per year. However, the Schiller Station still burned 421,670 tons of coal in 2008, two years after the plant began operating. Compared to the previously coal-fired Unit 5, emissions estimates for the biomass burner are 70 percent lower for nitrogen oxides, 95 percent lower for sulfur dioxide, and 90 percent lower for mercury. These reduced emissions help the Schiller Station meet the requirements of the New Hampshire Clean Power Act.

North Carolina

• University of North Carolina Cogeneration Facility Possible Conversion to Biomass -- In 2009 students, administrators and professors created a Climate Action Plan which recommended co-firing coal with torrefied biomass. Proposals being evaluated by the University include 100% biomass scenarios.
• Coastal Carolina Clean Power: Kenansville, North Carolina -- In 2008 the old Cogentrix 32MW coal-fired generating plant in Kenansville, NC was converted to run on biomass. This cogeneration plant now uses waste wood to create 25MW of electricity and sends waste heat to an adjacent textile manufacturer.
• Primary Energy Roxboro Power Plant & Southport Plant, North Carolina -- Capital Power Corp., an Alberta, Canada-based company, purchased EPCOR Power in 2008 and began transitioning the plants off of coal with the use of biomass. As of early 2010 Capital Power Corp. had spent $80 million making improvements to both the Primary Energy Roxboro Power Plant and the Southport Plant to co-fire woody biomass and tire-derived fuel along with coal.
• Wood Fuel Developers company announced plans to build an $18.7 million pellet plant in Greensville County. In 2011 the company announced an $8.6 million project to replace a closed particleboard plant in Waverly with its new manufacturing center for wood pellets.
• Enviva, a Richmond VA-based energy company, is building a wood-pellet factory in Ahoskie, N.C. at a former Georgia Pacific lumber facility. Enviva also purchased a port terminal on the Elizabeth River in Chesapeake for $11.7 million to export its wood biomass products.
• Franklin Pellets, a newly formed partnership between Multifuels and CMI, is considering a wood pellet shop at International Paper in Franklin.

Ohio

• R.E. Burger power plant: Shadyside, Ohio -- Once scheduled for biomass conversion, this plant was instead be shut down in 2010. Originally, on April 1, 2009, FirstEnergy announced that it was retrofitting the R.E. Burger power plant in eastern Ohio to produce electricity from woody biomass instead of coal, which would make it one of the largest such facilities in the U.S. The conversion of the 300 MW plant would have cost about $200 million. FirstEnergy had faced an April 2 deadline to either close the plant, install $330 million in pollution controls, or convert to biomass. In November 2010 First Energy decided not to pursue the biomass option for economic reasons.

Ontario

• Ontario shutting 4 plants, considering conversion for remaining 11 plants - In September 2009, Ontario Power Generation announced it will shut down four of its 15 coal-fired power plants in late 2010. The closures include two of eight units at Nanticoke Generating Station, and two of four units at Lambton. The four plants represent about 2,000 megawatts of total generation capacity. The closure of the four units, in addition to the 2005 closure of Lakeview Generating Station in 2005, will reduce the Canadian province's coal capacity by 40 percent. OPG said it would continue to assess converting its remaining 11 units to other types of fuel such as biomass, beginning with the conversion of Atikokan Generating Station by 2012.

Oregon

• Boardman Plant, Eastern Oregon-- On January 14, 2010 it was announced that Portland General Electric will be closing its 601 MW Boardman Plant twenty years ahead of schedule. The plant will close in 2020 instead of 2040. The plant was originally going to invest more than a half billion dollars in pollution controls (scrubbers) by 2017 to comply with EPA and state clean air regulations, then keep it running until 2040. Instead, the company wants regulators to allow it to make a $45 million investment by 2011 to partially clean up its emissions of mercury and oxides of nitrogen, then operate the plant until 2020. The Oregon Sierra Club and Friends of the Columbia Gorge argue, that while a 2020 close date is better than a 2040 closure, it is still more economical for the plant to shut its doors in 2014. On February 1, 2010 it was announced that PGE was considering using biomass to continue operating the plant after it ends its use of coal in the future. PGE is said to be considering if it can replace all of the millions of tons of coal it burns every year at Boardman with plant based material that has been pre-treated through a process called torrefaction. While still in experimental phases, torrefaction produces a substance similar to coal, and is also energy intensive to produce. Critics on the other hand cite that no commercial size torrefaction facilities exist and it is still not clear how much carbon will be used in the process of torrefaction.

Tennessee

• Tennessee Valley Authority Considers Conversion to Biomass- TVA announced in August 2010 that they were going to idle its Shawnee Fossil Plant's Unit 10 and were considering transferring the plant to biomass. Shawnee Fossil Plant is a coal-fired power station located about 10 miles northwest of Paducah, Kentucky, on the Ohio River.

Virginia

• Altavista Power Station, Hopewell Power Station and Southampton Power Station, Virginia -- In April 2011, Dominion Resources announced that its subsidiary Dominion Virginia Power, has decided use biomass instead of coal in three of its power stations: Altavista Power Station, Hopewell Power Station and Southampton Power Station. The plants will mainly use waste wood left from timbering operations as a source of fuel. If approved by the local authority and the regulators will begin production from the converted units in 2013. The units can presently produce 63 megawatts (MW) power each and are only used when demand is at its peak. After conversion, these units will produce 50 MW each.

Wisconsin

• Stoneman Generating Station: Cassville, Wisconsin --In June 2008, DTE Energy announced plans to purchase the E.J. Stoneman Power Plant from Integrys and convert its 50MW of coal capacity to burn wood waste. At the time of the announcement, DTE hoped begin the conversion in 2009. As of November 2009, DTE expected to begin operating the plant in Summer 2010.
• Bay Front Station: Ashland, Wisconsin-- In October 2008, Xcel Energy announced plans to spend over $55 million to convert the last remaining coal-fired unit at its Bay Front Power Plant to biomass. The conversion will enable the facility to use 100 percent biomass in all three boilers. Xcel submitted an application to the Public Service Commission of Wisconsin in February 2009. If approved, construction could begin in 2010 and operation in late 2012. The facility primarily burns waste wood from area forest harvesting operations. The existing biomass incinerators burn about 200,000 tons of waste wood each year. When the project is completed, the plant will use another 185,000 to 250,000 tons per year and will be capable of generating enough electricity for 40,000 homes. According to Xcel, the project will reduce emissions of nitrogen oxides by approximately 50 percent, sulfur dioxides by over 85 percent, and particulate matter by 90 percent.
• Charter Street Heating Plant: Madison, Wisconsin-- In February 2009, Governor Jim Doyle announced that the University of Wisconsin's Charter Street Heating Plant will phase out coal. Under the plan, one of five boilers at the plant will be converted to burn biomass, including cornstalks, switch grass, and wood chips, in an effort to generate 25 percent of the state's energy from renewable resources by the year 2025. Four coal boilers will be converted to burn natural gas. The project, which is estimated to cost $200 million to $300 million, will eliminate the burning of over 100 tons of coal per year.

Resources

External resources

• Coal plant conversion projects
• Biomass power generation
• "Pellet Fuels Institute", Arlington, Va.