Both the Quartz Solar UI and API docs use language that might not be familiar to those new to the energy sector, short-term solar forecasting or the UK power grid. Never heard of a GSP? No problem. This glossary is here to try to get you up to speed.

Please let us know if there are definitions you think should be added!

• Distribution Network Operator (DNO): DNOs operate the electric power distribution system in a particular region of a country and are responsible for delivering electricity to the end user. A DNO is separate from the transmission system operator (TSO), the entity responsible for power delivery to the distribution network in a region. A county might have many DNOs. The UK has 14.
• Electricity System Operator (ESO): ESOs ensure that the current supply of electricity on a country’s power grid meets demand. In the UK, National Grid ESO is responsible for balancing the country’s grid.
• Grid supply point (GSP): In the UK, grid supply points supply the Great Britain electricity transmission network. The Nowcasting App map displays all 316 GSPs using their geospatial boundaries.
• Gigawatt (GW): A gigawatt is equal to 1,000 megawatts and is a unit of power used to describe electrical power production. The UK has a solar generation capacity of around 14 GW.
• Megawatt (MW): A megawatt is a unit of power used to describe electrical power production. At the GSP level, for example, solar power production is measured in MW. This is not to be confused with MWh (megawatt hour), which is a unit of energy equivalent to a steady power of one megawatt running for one hour.
• Normalization: A value is said to be normalized when rendered as a percentage of a total value. In the Quartz Solar UI’s case, this means PV actual values or PV forecasted values can be presented as a percentage of total installed PV generation capacity. A user might find normalized values meaningful when comparing forecasted and actual PV generation between GSPs with different installed PV capacities.
• PV_Live: PV_Live is Sheffield Solar’s API that reports estimate PV data for each GSP and then updated truth values for the following day. These readings are updated throughout the day, reporting the actual or truth values the following day by late morning UTC. In the Quartz Solar UI, PV_Live’s estimate and updated truth values on both the national and GSP level are plotted alongside the Quartz Solar forecast values.
• Transmission system operator (TSO): The TSO uses fixed infrastructure to transport electrical energy on the national or regional level.
• N-hour forecast: In the UI, the forecast comes in 4 steps: 1, 2, 4, and 8 hours. In the API, this can be set to an integer amount in minutes, which will be rounded to the nearest initialization time if not a round hour value, set using the forecast_horizon_minutes parameter on relevant forecast routes. More information on the N-hour forecast can be found on the Features page here.