Who runs the network
Your electricity supplier sells you power; the wires and substations belong to a separate company, the distribution network operator. In Liverpool, as across Merseyside, Cheshire and North Wales, that is SP Energy Networks. Solar panels feed into its network whenever they make more than the house is using at that moment, which is why it needs to know they are there.
Most houses have a single-phase supply. Some larger or newer homes have three phases, which raises the amount that can connect on the simple route; your installer will check which you have.
G98: tell, then confirm
Small generators connect under an industry standard called G98. SP Energy Networks says that for a single generator of less than 16 amps per phase, 3.68 kW, you must inform it of the proposal before or at the time of commissioning, which is a legal obligation under the Electricity Safety, Quality and Continuity Regulations 2002 (SP Energy Networks). The installation commissioning confirmation, with the final circuit diagram and test report, then has to reach it within 30 days, and it says it will not normally object to the connection if G98 and the law are followed.
| G98 | G99 | |
|---|---|---|
| Size | Under 16 A per phase (3.68 kW single-phase) | Above that, or several units together |
| Network involvement | Told before or at commissioning | Applied to, and must agree, before connection |
| Paperwork after | Commissioning confirmation within 30 days | As set out in the network's agreement |
| Typical case | A small to medium roof system on its own | A large system, or solar with a battery taking the total over the limit |
A 3 kW system on a south roof in central Liverpool would make about 2,895 kWh a year (our arithmetic from PVGIS) and sits comfortably within G98 on its own.
G99: ask first
Above the G98 limit, or where several generating units add up past it, the connection falls under G99, and the network operator has to assess and agree it before it is switched on. That can take time and occasionally leads to conditions or costs if the local network needs work. Ask any installer quoting a larger system whether it needs G99, who will apply, and how long their recent applications to SP Energy Networks took.
Batteries and export limiting
A home battery has its own inverter, and that counts towards the same limit. So a system that is comfortably within G98 on its own can cross it once a battery is added. Some designs use export limiting: controls that stop the system sending more than an agreed amount to the network at once. The network operator still has to accept the arrangement. The battery page covers sizes and costs, including the 2025/26 median of £890 per kWh for 6 to 11 kWh batteries (DESNZ).
The supplier side
The network connection and the money for exported power are separate matters. To be paid for exports you need a meter that records them, usually a smart meter, and an export tariff from a supplier, which may or may not be the company that sells you electricity; larger suppliers must offer one at a rate above zero (Ofgem). The supplier will ask for your MCS certificate. See export payments.
Papers to keep
- A copy of the G98 notification or the G99 agreement.
- The commissioning confirmation and test report.
- The MCS certificate and electrical installation certificate.
- Warranties for the panels, inverter, any battery and the workmanship.
Ask for them in the contract; the installer checklist lists them. For what the system will cost, see solar costs in Liverpool.