The PV_Forecast service supplies forecasts of nationally- and regionally-aggregated electricity generation from solar Photovoltaics (PV) connected to the GB transmission network. Sheffield Solar currently run three tiers of PV_Forecast: Nationally-aggregated, regionally-aggregated by DNO License Area (a.k.a PES or GSP Group) and regionally-aggregated by Grid Supply Point (GSP). The Sheffield Solar research group is formed in the Physics & Astronomy department, at the University of Sheffield, as part of the Grantham Centre for Sustainable Futures. It works to bridge the gap between the research lab and how solar photovoltaic (PV) technology is used in the real world and to understand its performance and impact.