Electricity infrastructures are crucial for economic prosperity and underpin fundamental energy services. This article provides global datasets on installed power plant capacities, transmission and distribution grid lengths as well as transformer capacities. A country-level dataset on installed electricity generation capacities during 1980 to 2017, comprising 14 types of power plants and technologies, is obtained by combining data from three different online databases. Transmission grid lengths are derived from georeferenced data available from OpenStreetMap, augmented with data from national and international statistics. Data gaps are filled and historical developments estimated by applying a linear regression model. Statistical data on distribution grids lengths are collected for 31 countries that make up almost 50% of the global electricity consumption. Estimates for distribution grid lengths in the remaining countries are again obtained through linear regression. Data on installed transformer capacities are sparsely available from market intelligence reports and specialist journals. For most countries, they are estimated from typical transformer-to-generator ratios, i.e. based on power plant capacities. Global generation capacity expansion since 1980 was dominated by coal-fired (mainly China and India) and gas-fired plants (mainly industrialized countries and Middle East). Solar and wind power accounted for the second and third largest capacity additions since 2010 (after coal-fired plants). The total length of transmission circuits worldwide is estimated at 4.7 million kilometres, and the length of distribution grids between 88 and 104 million km. China accounts for 41% of the expansion of global transmission grids, and 32% of the expansion of distribution grids since 1980. In 2017, China's electricity grids were approximately as large as the grids of all western industrialized countries combined. The globally installed capacity of transformers is estimated between 36 and 45 Teravolt-Ampere, with transmission and distribution transformers accounting for above 40% each, and generator step-up transformers for the rest. The data provided in this article are used for estimating global material stocks in electricity infrastructures in the related research paper [1] and can be used in energy system models, for econometric analyses or development indices on country level and many more purposes.