Q: What is the difference between G98 and G99?

G98 is a "fit and notify" process for small generation up to 16 A per phase (≈3.68 kW single-phase, ≈11 kW three-phase) — you can install and commission, then notify the DNO within 28 days. G99 applies above those limits and requires a full application and DNO approval before energising.

Q: Do I need DNO approval for solar panels?

A single-phase solar PV or battery system up to 3.68 kW (16 A) is a G98 notification — no prior approval, just notify within 28 days. Above that, or where existing generation pushes the total over the limit, a G99 application and DNO approval are needed first.

Q: How long does a G99 application take?

Budget around 45 working days (≈10–12 weeks) for a G99 application, as the DNO may carry out a network study and could require reinforcement. Do not energise the generation equipment until written approval is received.

Q: Does battery storage need a DNO application?

If the battery can export to the grid or run in parallel with the supply, yes — it follows the same G98/G99 thresholds as other generation, based on the inverter's output rating plus any existing generation. A battery that never exports and only charges from the grid is treated as a load.

Question 1

What is the difference between G98 and G99?

Accepted Answer

G98 is a "fit and notify" process for small generation up to 16 A per phase (≈3.68 kW single-phase, ≈11 kW three-phase) — you can install and commission, then notify the DNO within 28 days. G99 applies above those limits and requires a full application and DNO approval before energising.

Question 2

Do I need DNO approval for solar panels?

Accepted Answer

A single-phase solar PV or battery system up to 3.68 kW (16 A) is a G98 notification — no prior approval, just notify within 28 days. Above that, or where existing generation pushes the total over the limit, a G99 application and DNO approval are needed first.

Question 3

How long does a G99 application take?

Accepted Answer

Budget around 45 working days (≈10–12 weeks) for a G99 application, as the DNO may carry out a network study and could require reinforcement. Do not energise the generation equipment until written approval is received.

Question 4

Does battery storage need a DNO application?

Accepted Answer

If the battery can export to the grid or run in parallel with the supply, yes — it follows the same G98/G99 thresholds as other generation, based on the inverter's output rating plus any existing generation. A battery that never exports and only charges from the grid is treated as a load.

DNO Application Checker (G98 / G99)