The Operation Performance Monitoring Division of India's Central Electricity Authority (CEA) has published detailed data on the capacity and generation of electricity from traditional power sources (coal, natural gas, diesel, nuclear, and large hydro) in monthly reports that are available online from January 2008. Only recently (from July 2019) have these reports been made public in machine-readable form, although in a format that requires processing before it can be used in analysis. This new dataset is a result of processing all editions of sub-report 16 - in first PDF and thereafter Excel format - over the 156 months from January 2008 through December 2020. Both capacity and generation are collated at state level by generation type. Earlier reports included natural gas stations in 'thermal' totals, while these are now excluded. For this dataset, station-level data has been used to produce a complete series of natural gas generation and capacity, with thermal having a consistent definition over the entire time period of including coal, lignite, and diesel, but excluding natural gas. Further, two aggregations have been made to produce consistent state series over the period. Earlier reports separated Bhakra Beas Management Board (BBMB) stations from Himachal Pradesh, and these have been combined to produce a consistent Himachal Pradesh series. In addition, earlier reports separated Damodar Valley Corporation (DVC) stations, and these have been moved at station level into West Bengal and Jharkhand, to give consistent series for those two states. All reports include generation in the same month of the previous year, and this has been used to add generation in 2007. Capacity is presented in MW (megawatts) while generation is presented in GWh (gigawatt-hours). The dataset does not include wind, solar, biomass, waste, or small hydro, data for which are not available at state level before March 2019.