This terminology standard provides terms and definitions in the subject area of grid integration of renewable energy sources. The technical issues of grid integration mainly focus on the issues caused by renewable energy generation with variable sources and/or converter based technology, such as wind power and photovoltaic power generation. Some renewable generations such as hydro power and biomass power with a relatively continuously available primary energy source and a rotating generator are conventional sources of generation, and so not covered in this document. The intention of this International Standard is to answer the question "what do the words mean" and not "under what conditions do the terms apply".