page_title: Pellet fuel
section_title: Energy output and efficiency
hierarchical_section_title: Pellet fuel / Energy output and efficiency
caption_attribution_description: English: Inside a woood-pellet heater Deutsch: Brenteller (Unterschubfeuerung) im Inneren eines Pellet-Ofens
context_page_description: Pellet fuels are biofuels made from compressed organic matter or biomass. Pellets can be made from any one of five general categories of biomass: industrial waste and co-products, food waste, agricultural residues, energy crops, and virgin lumber. Wood pellets are the most common type of pellet fuel and are generally made from compacted sawdust and related industrial wastes from the milling of lumber, manufacture of wood products and furniture, and construction. Other industrial waste sources include empty fruit bunches, palm kernel shells, coconut shells, and tree tops and branches discarded during logging operations. So-called "black pellets" are made of biomass, refined to resemble hard coal and were developed to be used in existing coal-fired power plants. Pellets are categorized by their heating value, moisture and ash content, and dimensions. They can be used as fuels for power generation, commercial or residential heating, and cooking. Pellets are extremely dense and can be produced with a low moisture content that allows them to be burned with a very high combustion efficiency.
context_section_description: The energy content of wood pellets is approximately 4.7 – 5.2 MWh/tonne (~7450 BTU/lb), 14.4-20.3 MJ/kg.
  High-efficiency wood pellet stoves and boilers have been developed in recent years, typically offering combustion efficiencies of over 85%. The newest generation of wood pellet boilers can work in condensing mode and therefore achieve 12% higher efficiency values. Wood pellet boilers have limited control over the rate and presence of combustion compared to liquid or gaseous-fired systems; however, for this reason they are better suited for hydronic heating systems due to the hydronic system's greater ability to store heat. Pellet burners capable of being retrofitted to oil-burning boilers are also available.
caption: Wood-pellet heater
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