Wood has been burned for energy for millennia and is valued globally as an affordable and highly decentralized energy source. In 2016, wood and wood waste supplied 2% of total annual U.S. energy consumption. However, interest in wood as a renewable energy source has increased due to improvements in conversion technology, forest management challenges and a demand for non-fossil energy sources.

Types of wood-based energy:

Direct Consumption – Wood can be burned in a boiler to heat water and produce steam.  The steam can be used to power machines or heat buildings.  Using steam to rotate turbines generates electricity. Commonly, both heat and electricity are utilized in a process known as co-generation, or combined heat and power (CHP).

Convert Wood to Gas – Gasification uses high heat and pressure, in a low oxygen environment to produce syngas.  Biogas is produced from anaerobic digestion, a process by which microbes break down biomass in the absence of oxygen.  Syngas and biogas are similar to natural gas and can be used in electricity generation.

Convert Wood into Transportation Fuels – Pyrolysis is a thermochemical conversion process that converts biomass into liquid fuel and biochar, along with other co-products.  Cellulosic ethanol can be produced from wood, grasses or crop residues through fermentation, similar to the process that converts corn grain to ethanol.  Methanol, also called methyl alcohol, is generated from anaerobic digestion or through a secondary conversion of syngas.  Oils extracted from wood can be combined with alcohol and a catalyst in a process called alcoholysis to produce diesel fuel.