Do Restaurant Solar Panels Need a G99 Application? The 3.68 kW Rule

Restaurant solar panels on a hotel almost always need a G99 application to the District Network Operator, because the simplified G98 route stops at 16 A — 3.68 kW — per phase and a commercial kitchen’s array is tens of kilowatts. The grid study that follows is usually the longest single item in the programme, which is why it belongs at the front of the project rather than after the panels have been chosen. This post sets out the threshold from the source documents and what it means for sequencing an F&B solar project; the full cost, funding and process picture is in our guide to restaurant solar panels for hotels.

The threshold, from the engineering recommendation

Two documents define the boundary between the simple and the full connection route.

ENA Engineering Recommendation G98 (Issue 1, Amendment 7) covers micro-generation “up to and including 16A per phase”. SSEN’s connection guidance states the same limit in kilowatts: “Installation of up to 3.68kW per phase at one property”. Anything above 16 A / 3.68 kW per phase falls under G99, the connection procedure for larger generators, under which the DNO assesses the network before the array can be connected.

A worked check shows how low the line sits. A single 4 kW inverter on a 230 V supply draws 4,000 ÷ 230 = 17.39 A — already just over the G98 limit. One domestic-sized inverter is enough to cross it.

What a kitchen-scale array draws

A hotel restaurant array is sized to the kitchen and refrigeration base load, not to a domestic roof. Modelled from typical UK hospitality demand:

Operation (modelled)	Array sized to base load	Approximate current per phase (three-phase supply)
Hotel bar and 40-cover restaurant	25–35 kW	~36–50 A
Full-service 100-cover hotel restaurant	50–70 kW	~72–100 A
Restaurant-led hotel (80 covers + 12 rooms)	110–130 kW	~160–190 A
Banqueting hotel with event kitchen	180–250 kW	~260–360 A

Every row is a multiple of the G98 limit. There is no restaurant solar project of any commercial scale that avoids a G99 application, and any proposal suggesting otherwise is either describing a domestic-sized array or misreading the threshold.

A note on a common error: some published guidance quotes the G98 limit at more than four times its true value, the result of reading the 17.39 A current figure as if it were kilowatts. The limit is 16 A — 3.68 kW — per phase, and a buyer who relies on the inflated figure will plan for a simple connection that the DNO will not grant.

Why the DNO study goes first

Under G99 the DNO studies whether the local network can accept the generation. On a constrained network the answer can include reinforcement or a connection upgrade, with cost and lead time attached. The response runs to months, and on a hotel programme it is normally the single longest item — longer than planning, longer than the install itself.

The practical consequences for an F&B project:

1. Submit the G99 application at desk-feasibility stage, as soon as the array size is known from the half-hourly data. It runs in parallel with design, any planning or listed building consent, and brand engineering approval.
2. Order nothing until the DNO offer is in hand. The offer fixes the export limit and any upgrade cost; equipment specified before it is equipment that may have to change.
3. Design the kitchen circuits around the offer, not the other way round. Where the DNO caps export, the array is sized to self-consumption — which, for a kitchen with 24/7 refrigeration and daytime cooking load, is usually the right size anyway.
4. Know which DNO you are dealing with. The process differs by region: see the site’s guides to UK Power Networks, Northern Powergrid and SP Energy Networks.

The kitchen’s own contribution to the case

The same load that makes a G99 application inevitable is what makes restaurant solar panels pay. Walk-in chillers and blast freezers run continuously at a constant 1.5–4.5 kW per unit; extraction, dishwashing and cooking load peak through breakfast, lunch and dinner service; front-of-house refrigeration runs all day. Modelled self-consumption for an F&B-led hotel is 90–95%, so the array is sized to displace grid electricity at the full retail rate rather than to export. The G99 step is the price of admission to that profile, not an obstacle to it — the wider hospitality solar panel installations guide sets the same step in the context of the whole programme.

Sources

• ENA Engineering Recommendation G98, Issue 1 Amendment 7 — “up to and including 16A per phase”.
• SSEN connection guidance — “Installation of up to 3.68kW per phase at one property”.
• National Grid Electricity Distribution G99 connection procedures — connections above the G98 limit.

Get a fixed-price quote

Free desk feasibility from your half-hourly meter data, with the array sized to the kitchen and refrigeration base load and the G99 application scoped before anything is ordered — get a free hotel solar quote.