Wood is the most widely available and least expensive biomass fuel available. Firewood is normally sold in units called cords. A cord of wood is a neat stack measuring four feet wide by four feet high and eight feet long. The heat content of a cord will vary depending on the species of wood. A cord of mixed softwood will have a heat value of 17 or 18 million BTU and a cord of mixed hardwood will have a heat value of 27 to 29 million BTU. By way of comparison a gallon of No. 2 fuel oil has a heat value of 140,000 BTU per gallon and propane has 93,000 BTU per gallon. Please use our fuel cost comparison tool to calculate the relative fuel costs in your area.
Wood Pellet fuel is manufactured from milled wood particles including waste wood and, less commonly, bark, which are pressed through dies at very high pressure.
Wood Pellets can be purchased in bulk or in 20 or 40 lb bags. The energy content of pellets is more constant than corn because of lower moisture content (4-8%). As a rough approximation, 17.5 lbs of wood pellets provide the same amount of heat as a gallon of heating oil. With these characteristics, wood pellets burn very efficiently. They are also very easy and safe to transport and store. Wood pellets have an average net BTU rating of 8,200 BTU/lb.