PJM Interconnection is a regional transmission organization (RTO) operating the electric grid in all or parts of 13 states and the District of Columbia, including PA, OH and WV. It is the largest competitive wholesale electricity market in the U.S. (second largest in the world), with more than 1,000 companies (1,376 generation sources) as members, serving 65 million customers with 177 gigawatts of generating capacity. It’s yuge! EIA published numbers yesterday quantifying natural gas-fired generation in PJM. The upshot: natural gas has eclipsed coal in electric generation in PJM, and PJM uses more natgas plants in both raw numbers and as a percentage of electricity generated, than any other power grid.