|Community-Scale Biomass Energy: The Facts|
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When community-scale biomass energy systems are well-designed, well-run, and sustainably supplied, it is a positive, proven, renewable energy option that can be practical and safe, can strengthen our economy and security, and can help ease the urgent strain on our planet’s ecosystem. And, in regions throughout the United States with abundant forest resources, it is available now.
Community-scale biomass energy systems burn biological material—most often wood from low-quality trees—in highly efficient, high-temperature combustion systems to produce heat. Sometimes, these systems also produce a certain amount of electric power (this is called CHP, combined heat and power). But the most efficient use of biomass for energy is to provide space heating and domestic hot water. Community-scale systems typically provide this to single buildings, such as schools and hospitals, or to groups of buildings such as college campuses, industrial parks, or whole towns or cities through “district heating” systems.
Community-scale biomass systems that produce heat or CHP are different from electric power plants, which are generally much larger and mainly produce electricity for broad distribution. Biomass-fueled technology is only about 20-25 percent efficient at producing electric power; at producing heat, it is 70-90 percent efficient. Power plants sometimes (though this is rare) sell the excess heat they generate, where it is economically feasible and if there is an appropriate user nearby; this is only 40-45 percent efficient. Technology is also being developed that can use biomass to produce liquid biofuels. Community-scale thermal applications are the most efficient biomass energy technologies—they do the best job of turning biomass fuel into energy, with the least waste.
Systems of this type have been in use since the early 1980s, and have built a track record of safety and reliability. Today, a growing number of community-scale systems, most fueled with woodchips and some with wood pellets, are delivering heat and hot water to schools, businesses, colleges, hospitals, city centers, and whole communities across the northern United States, Canada, and north and central Europe.
Biomass fuel can be used in a wide range of technologies, from home woodstoves to power plants. Because community-scale thermal systems combine high-efficiency combustion with sophisticated emission controls, this technology meets and exceeds all emission-safety standards, while providing heat energy at relatively stable fuel prices from a local fuel source.
When wood fuel is harvested responsibly from well-managed forests, community-scale biomass energy is a sustainable whole system. It keeps energy dollars circulating in the local and regional economy, by using a renewable fuel that is harvested nearby—and its carbon emissions are re-captured as the forests that supply the fuel continue to grow. In contrast, fossil-fuel systems extract carbon that is buried underground in geological deposits, then add it to the atmosphere over time.
Finally, by developing a reliable, local market for low-quality wood, biomass energy can create a new financial incentive for forestland owners to manage their forests for long-term productive health, lessening the pressure to “high-grade” (cut only the most valuable trees and leave the rest). The revenue stream for biomass fuel can help landowners make ends meet, also relieving the pressure to sell woodland for development.
Benefits of Using Biomass at the Community Scale
Modern Community-Scale Biomass Energy Systems Use Sophisticated Emission Controls
Biomass energy systems emit 1/6 of the sulfur oxides, which contribute to acid rain, than do oil-fired systems. Nitrogen oxide emissions are about the same as oil.
When Their Fuel Is Harvested Responsibly from Sustainably Managed Forests, Biomass Systems Can Be Low-Carbon, or Carbon Neutral Over Time
Good forest management is essential to realizing the carbon benefits of biomass energy. Key factors include: where trees are harvested, how they are harvested, how this plays out over the landscape and over time, and whether management practices support long-term forest health. It is also important that biomass energy systems be well-designed and efficiently run. When these positive factors are in place, converting from oil- or gas-fired energy to biomass can reduce net CO2 emissions by 75-90 percent.
A Well-Managed Biomass Fuel Industry, Coupled with Sustainable Growth in Demand, Creates New Incentives to Protect and Preserve the Working Forest Landscape
Image Captions (from top to bottom)
A typical below-grade woodchip storage bin at a public school.
Woodchips being conveyed from the storage bin to to the boiler room.
The 2010 installation of Middlebury College in Middlebury, Vermont exemplifies a community-scale biomass application.
Woodchips burning inside the combustion chamber of a biomass boiler.
The chipping of low-grade wood from harvesting operations in the forest.