The process of creating energy in the form of electricity and/or heat from the primary treatment of waste, or the processing of waste into a fuel source, is known as waste-to-energy (WtE) or energy-from-waste (EfW). WtE is an energy recovery method. Most WtE processes produce a combustible fuel commodity, such as methane, methanol, or ethanol, or generate electricity and/or heat directly through combustion. synthetic fuels, for example. Waste-to-energy systems or technologies come in a variety of sizes. The mass-burn method is the most popular, in which unprocessed municipal solid waste is burned in a massive incinerator with a boiler and generator for electricity production. Another sort of technology, which is less popular, processes municipal solid waste to remove the majority of non-combustible elements and produce refuse-derived fuel (RDF).