The renewable electricity production tax credit (PTC) is a per kilowatt-hour (kWh) federal tax credit included under Section 45 of the U.S. tax code for electricity generated by qualified energy resources.
Source: United States Environmental Protection Agency

The PTC provides a corporate tax credit of 1.1 cents/kWh for landfill gas, open-loop biomass, municipal solid waste resources, qualified hydropower, and marine and hydrokinetic (150 kW or larger). Electricity from wind, closed-loop biomass, and geothermal resources receive 2.2 cents/kWh. Projects that receive other government grants or subsidies receive a discounted tax credit.