WHAT ARE PELLETS?
Pellets are clean heat.
Wood pellets, already a staple in Europe’s energy sector, are gaining popularity in the United States—especially where significant energy is used for heat—as people realize both the ecological and economical importance of sustainability. Wood pellets offer a completely sustainable alternative to other fuel sources. They burn clean, and, because of health and air quality control considerations, wood pellets are preferable to coal for electricity generation. Produced without additives and part of the natural carbon cycle, wood pellets are net neutral—generating no increased greenhouse gas emissions—if the pellet source material comes from sustainably managed forests or forestry residuals.
1,000,000 homes in the US currently use wood pellet stoves for heating. Convenient and widely available, residential wood pellets are supplied on a small scale and commonly in bagged form. Increasingly, factories, housing complexes, and office buildings, especially in Europe, are using wood pellets to provide heat on a larger scale. Electric utility coal plants in Europe have begun incorporating wood pellets in their production process because of government mandates for pollution and greenhouse gas emissions regulation. This forward-looking use of combined fuel sources for electricity generation is the future of clean, ecologically sound energy creation in the United States.
Pellets are more efficient wood.
Pellets are compressed wood. The idea that wood makes a great fuel source is ancient, but pellet manufacturers are transforming the process to make wood burn more cleanly and efficiently. Much of the pellet material comes from waste sawdust, shavings, and chips remaining after lumber production; this waste is then compacted into tiny, dense pellets, which burn more efficiently than other forms of wood. Pellets are manufactured with 100% biological materials pressed through small holes in a spherical machine that binds the pellets together. Pellets have a far higher combustion efficiency because the binding process reduces moisture to less than 10%, compared to that of an average log, which is typically 50% moisture by weight. Pellets’ uniform size, shape, and weight—usually 1/2-3/4 inch (1.2-2 cm) in length by 1/4-1/3 inch (6-8 mm) in diameter—make them relatively easy to transport and store, as compared to wood logs or wood chips. Pellet uniformity also allows a machine to measure fuel quantity accurately, in order to feed in a more precise amount of fuel to make heat or electricity output.
Three grades of pellets are commonly available, distinguished by the amount of ash they produce when burned:
- Premium—ash content is less than 1%.
- Standard—ash content is between 1 and 2%.
- Industrial—ash content 3% or greater.
Because ash is a non-combustible mineral residue, it can be disposed of as inert solid waste. However, many people who burn wood pellets use the ash as fertilizer or compost.
Pellets are sustainable forestry.
While any wood could be used to form pellets, it is important to source biomass responsibly. Fortunately, sustainable wood material is plentiful in the United States. In the forest, we find it in two primary forms: understory and forestry residuals. The understory is a forest layer of small trees and plants that, if allowed to accumulate, can prove ruinous during forest fires by connecting the ground to the canopy, magnifying the effects of what could have been a harmless ground fire. Forestry residual debris encompasses all of the stumps, branches, and tops loggers leave behind and is often referred to as slash. When the understory and forestry residuals are left to decay in nature, they often harbor diseases that, if left to spread unimpeded, have the potential to infect whole forests. What’s more, their eventual decay in nature emits more methane than their incineration in pellet burners.
Forests benefit from regular tree management; ridding them of understory and residual waste can keep forests safe. Many trees can be responsibly and sustainably harvested to maintain forest efficiency. Planting, harvesting, and replanting biomass dedicated to energy production are key elements of an integrated biomass energy system. .
Pellets are responsible industrial waste recycling.
Biomass can also be sourced from the wood and paper industries; furniture, paper, and lumber factories inefficiently discard millions of tons of useable wood waste each year.