Glossary

The jargon, in plain English.

Solar, battery, grid and planning terms explained in a sentence or two. If we use a word you don't know, it should be here.

A

ALCAgricultural Land Classification: A grading of farmland from 1 (excellent) to 5 (very poor). A soil survey confirms the grade on a site. More →
Ancillary services: Services that help the grid stay stable, such as fast frequency response. Batteries can be paid to provide them. More →

BESSBattery energy storage system: A set of batteries, usually in containers, that stores electricity and releases it later. More →
BMV landBest and most versatile: Farmland graded 1, 2 or 3a. Planning policy steers solar towards lower grades where possible. More →
BNGBiodiversity net gain: A legal requirement in England for most new development to leave nature at least 10% better than before. More →

Capacity Market: A government scheme that pays sites to be available to generate, or reduce demand, when the grid is tight. More →
CfDContract for Difference: A government-backed contract that gives a renewable project a fixed price for its power for a set number of years.
Co-location: Putting two technologies on one site, such as solar and batteries, so they can share a grid connection.
Connection offer: The network operator’s formal offer to connect a site to the grid, with a date, a cost and conditions. More →

DNODistribution network operator: The company that runs the local electricity network in your area. In the South West, that is NGED. More →

EIAEnvironmental Impact Assessment: A detailed study of a project’s effects on the environment. Only needed for some larger or sensitive schemes.
EPC (build)Engineering, procurement and construction: The contract to design, buy the kit for and build a project. Not to be confused with an Energy Performance Certificate.
Export limit: A cap on how much power a site can send to the grid, often set when the local network is busy. More →

G98 and G99: The rules for connecting generation to the grid. G98 covers small systems. G99 covers larger ones and needs approval before connection. More →
Gate 2: The stage in the reformed grid queue where projects that meet the readiness tests get a firm place and date. More →
Glint and glare: Reflections from solar panels. An assessment checks they won’t affect drivers, homes, trains or aircraft. More →
Grid supply point: Where the national transmission network feeds the local distribution network. Its capacity affects every site below it.

Half-hourly data: A record of how much electricity a site uses in every half hour. It is the best starting point for sizing solar. More →
Heads of terms: A short summary of the main points of a deal, agreed before the full legal documents are drafted. More →

Inverter: The box that turns the direct current (DC) from solar panels or batteries into the alternating current (AC) the grid uses.

kW, kWp and MW: Units of power. kWp is a solar system’s peak output. 1,000kW is 1MW.
kWh and MWh: Units of energy: power used or made over time. Your bill is priced per kWh.

LPALocal planning authority: The council, or national park authority, that decides planning applications in an area. More →
LVIALandscape and visual impact assessment: A study of how a project will change the landscape and views from homes, roads and footpaths. More →

MCS: A certification scheme for small renewable systems up to 50kW. Larger systems are not covered by it. More →
Microgrid: A local energy system, with its own generation and often storage, that can run with the grid or on its own. More →
MRTPI: Member of the Royal Town Planning Institute: a Chartered Town Planner. More →

NESONational Energy System Operator: The public body that balances the electricity system in Great Britain and runs connections reform.
NGEDNational Grid Electricity Distribution: The DNO for the South West, Wales and the Midlands.
NSIPNationally significant infrastructure project: A very large project decided by the government, not the local planning authority. For solar in England, that means over 100MW. More →

O&MOperations and maintenance: Looking after a site once it is running: monitoring, repairs, cleaning and grass or grazing management.
Option agreement: An agreement giving a developer the right to take a lease later, once grid and planning are in place. More →

Permitted development: Building work allowed without a full planning application, within set limits. Many rooftop systems qualify. More →
PPAPower purchase agreement: A long-term contract to buy power at an agreed price. With a solar PPA, a funder pays for the system. More →
Pre-application advice: Early, informal advice from the local planning authority on a proposal before a full application goes in. More →
Prior approval: A light-touch check by the local planning authority on some permitted development, such as design or glare, before work starts. More →
Private wire: A direct cable from a generator, such as a solar farm, to a nearby user, without going through the public grid. More →

RTBReady-to-build: A site with land rights, a grid connection offer and planning consent, ready to fund and build. More →

Securities: Money, or a guarantee, a developer may have to put up to hold a grid connection while it is built.
SEGSmart Export Guarantee: The scheme that makes larger energy suppliers pay you for electricity you export to the grid. More →
Substation: Where the grid changes voltage and lines meet. Being close to one with spare capacity is key for a solar or battery site.

TIATransmission impact assessment: A check on whether a project affects the national transmission network. Most projects under 5MW no longer need one. More →

VPPVirtual power plant: Many small energy assets, such as batteries and solar, controlled together so they act like one power station. More →

Yield: How much electricity a solar system makes in a year, often given in kWh per kWp. More →

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