1.2.6 Electric generation capacity

Massachusetts’ electric era was launched at the dawn of the 20th with small-scale hydropower in multiple municipalities in the Connecticut River watershed. Petroleum-based generation expanded rapidly in the 1960s and 1970s, and major pumped storage hydropower was built on the Connecticut and Deerfield Rivers (1972-74).

Massachusetts entered the nuclear era with the Yankee Rowe plant (1960) and Pilgrim Nuclear Power Station (1972) that added substantial baseload power generation. Natural gas expanded beginning in the 1990s due to industry restructuring, environmental regulations, and efficient, cost-effective natural gas combined-cycle technology. By 2003, the Mystic Station in Everett had 1.4 GW of natural gas-fired generation capacity. In recent years, Massachusetts has seen rapid growth in utility-scale solar deployment under its SMART and related incentive programs. Simultaneously, utility-scale battery storage has come online, supported by the state’s Energy Storage Initiative and other programs.

1. Electric generation capacity by source: The U.S. Energy Information Administration’s EIA Form 860 database prvides unit-level information on every electric generator in the United States that is connected to the electric grid. Each record corresponds to a single generator at a power plant and includes identifying information such as the plant name, operator, utility ownership, and geographic location (state, county, latitude, and longitude). The dataset also specifies the generator’s status (operating, standby, retired, proposed, or under construction), year of initial operation, and nameplate capacity, which is the maximum rated electrical output under specific conditions.The data include detailed technical and fuel-related attributes that describe how each generator produces electricity. This includes the prime mover type (e.g., steam turbine, combustion turbine, wind turbine, photovoltaic), energy source (coal, natural gas, solar, nuclear, etc.), and information on heat rates, capacity factors, and ownership structure for certain units.

Publication Date: August 2025