A biorefinery[1]​ is a facility that integrates biomass conversion processes and equipment to produce fuels, energy and chemicals from biomass. The concept of a biorefinery is analogous to that of the oil refinery, which produces multiple fuels and other products from this raw material.[2]​.

The International Energy Agency has defined biorefining as the sustainable processing of biomass into a variety of biocomposites (food, chemicals, feedstock) and bioenergy (biofuels, electricity or heat).

By producing multiple products, a biorefinery takes advantage of the various components of biomass and their intermediates, thereby maximizing the value of that biomass. A biorefinery could, for example, produce low volumes of high-value chemicals or nutraceuticals or high volumes of low-value liquid fuels, such as biodiesel or bioethanol.[3] At the same time it can generate electricity and heat, through cogeneration, for its own use and perhaps enough to sell the electricity locally. High-value products increase profitability, while high-volume fuels help meet energy needs, and the electricity produced helps lower energy costs and reduce greenhouse gas emissions from traditional power plants.

Although some existing facilities could be called biorefineries, the biorefinery itself still needs to be fully developed. Future biorefineries may play a larger role in the production of chemicals and materials that are traditionally produced from petroleum.

The fully operational Blue Marble Energy company has multiple biorefineries located in Odessa (Texas), Washington (state) "Washington (state)") and Missoula (Montana) "Missoula (Montana)").

Canada's first integrated biorefinery, developed with anaerobic digestion technology by Himark BioGas, is located in Hairy Hill, Alberta. The biorefinery uses organic sources separated from the Edmonton metropolitan region, manure and food processing waste.

Many examples of potential biorefineries have been proposed, starting with feedstocks such as tobacco, straw and waste from bioethanol production.[4]​.

The Chemrec technology for the gasification of black liquor and production of second-generation biofuels such as biomethanol "Methanol (fuel)") or BioDME is integrated by a pulp factory and uses waste products from the production of cellulose pulp from wood as raw materials.[5]​.