9.4 Adding Renewable Energy – Waste to Energy
Instead of hauling off non-recyclable municipal solid waste (MSW) to landfills, there are several options to convert it to energy. NWC can incinerate it on-site. The waste heat can be used to generate steam. One option is to use steam turbines to produce electricity. The exhaust fumes of the incinerator must be controlled so it’s not contributing to local air pollution.
The other option: ‘gasification’ is a unique process that transforms any carbon-based material, such as MSW, into energy without burning it. Instead, gasification converts the materials into a gas by creating a chemical reaction. This reaction combines those carbon-based materials (known as feedstocks) with small amounts of air or oxygen, breaking them down into simple molecules, primarily a mixture of carbon monoxide and hydrogen, and removing pollutants and impurities. What’s left is a clean ‘synthesis gas’ (syngas) that can be converted into electricity and valuable products. With gasification, MSW and other types of wastes are no longer useless, but feedstocks for a gasifier. Instead of paying to dispose of and manage the waste for years in a landfill, using it as a feedstock for gasification reduces disposal costs and landfill space, and converts those wastes to electricity and fuels.