Recycled energy, also known as waste heat to power (WHP), is the process of capturing heat discarded by an existing process and using that heat to generate electricity. In Colorado, the term recycled energy is more commonly used and qualifies under the states Renewable Electricity Standard (RES) as an eligible resource. Under the Colorado RES, recycled energy systems must have a nameplate capacity of 15 megawatts (MW) or less, convert the otherwise lost energy from the heat from exhaust stacks or pipes to electricity and not combust additional fossil fuel to be eligible. In addition, recycled energy does not include energy produced by systems that use waste heat from a process whose main purpose is the generation of electricity. In the industrial sector, most recycled energy streams are generated by kilns, furnaces, ovens, turbines engines, and other equipment. Waste streams suitable for recycled energy can also be generated at field locations including landfills, compressor stations, and mining sites.
While the potential economic and environmental benefits of CMM generated electricity are recognizable, an uncertain energy market and declining coal production impedes project development. Moreover, legal regulatory, and technical challenges make CMM project business risks and commercial feasibility difficult to assess, particularly at active mines where production can be highly variable.
Colorado's Renewable Energy Standard (RES) has been in effect since 2004, but in 2013, coal mine methane (CMM) and synthetic gas produced by pyrolysis of municipal solid waste (MSW) were added as eligible energy resources as long as the renewable energy projects are greenhouse (GHG) neutral. The purpose of this study was to develop a framework for project developers and the Colorado Public Utilities Commission (PUC) to assess the GHG-neutrality of specific CMM and pyrolysis projects that generate electricity in Colorado. The report and accompanying calculation tools will serve as guidance in the RES certification process. The calculations use GHG accounting principles and equations from internationally-recognized CMM and MSW project protocols. A coal mine methane-to-electricity project may include a combination of methane sources from CMM, ventilation air methane (VAM), and abandoned mine methane (AMM).
Recycled energy or waste heat to power (WHP) is the process of capturing heat discarded by an existing process and using that heat to generate electricity. Colorado's Renewable Electricity Standard (RES) requires systems to have a nameplate capacity of 15 megawatts (MW) or less, convert the otherwise lost energy from the heat from exhaust stacks or pipes to electricity and not combust additional fossil fuel to be eligible.
