Clean Energy and Renewable Portfolio Standards

One of the longest-standing strategies to advance renewable energy, renewable portfolio standards (RPSs) require a specific percentage or megawatt hour (MWh) of electricity sold by utilities in the state to be generated by renewable resources, such as wind, solar, and hydropower.

Several states opt for a clean energy standard (CES), which expands the definition of qualifying resources to zero-carbon energy sources that may not be considered renewable, such as nuclear energy. States can define what “renewable” and “clean” resources are under their RPS and CES, which is often the main distinction between the two policies, and in most cases a CES will include an RPS as part of the requirement. RPS and CES policies usually include a set of incremental milestones that increase the level of renewable or clean energy supplied to in-state consumers each year.

Typically, RPS and CES policies place the obligation of achieving these targets on the utility, and may establish different targets and timelines for municipal utilities, electricity cooperatives, and investor-owned utilities (IOUs). These entities are responsible for the planning processes, requests for proposals, and contracts required to ensure they deliver the requisite level of renewable or clean electricity in their energy supply.