Glossary of Terms Related to Wood Pellets
If you’ve wondered what some of the terms associated with wood pellets mean, this guide offers handy explanations.
Ash content: The amount of ash produced during combustion relative to the amount of fuel fed into the wood pellet stove. Ash content is one indicator of quality for wood pellet fuel. Ash content for wood pellets should be between one and three percent.
Biomass: Any biological material, such as wood or grass, that can be used as fuel. Biomass fuel is burned or converted in systems that produce heat, electricity, or both.
BTU: A BTU, or British Thermal Unit, is a measure of heat content or thermal energy. One BTU is the amount of energy needed to heat one pound of water one degree Fahrenheit, measured at its heaviest point. So, if you placed 16 ounces of water at 59°F into a stovetop pan and turned on the gas burner, it would take one BTU to raise the temperature of the water to 60°F. It takes about 1,200 BTUs to boil one gallon of water. For most people, a BTU is simply a gauge and way to compare the cost and efficiency of various heating and energy-producing technologies.
Clinkers: These are the result of impurities found in wood prior to it being pelletized. They can often be reduced by altering the air-to-fuel ratio on the stove.
Density: A way to measure the potential energy delivered to the stove by pellets, measured in pounds per cubic foot. Low-density fuels can cause a fire to go out without proper air-to-fuel ratios being in place.
Energy content: The total BTUs per unit of fuel. For biomass fuels, energy content can be considered on a dry or wet basis, since the amount of energy per pound of fuel is reduced with increased moisture content.
Fines: The scrap bits and pieces of broken pellets typically found in the bottom of the bag.
Fossil fuels: A group of combustible fuels, such as oil, propane, coal, or natural gas, formed from the decay of plant and animal matter that can be burned to produce energy. Liquid fossil fuels include oil; gaseous fossil fuels include propane; and solid fossil fuels include coal.
Moisture content: The total amount of water in a biomass fuel given as a percentage of the total weight of the fuel. Wood pellets, for example, typically have up to six percent moisture content, while woodchips have 40 percent and heating oil has zero percent.