UK Behind-the-Meter Solar and Storage - July 2026
July fleet market revenue came in down 29% on June, and South Wales's 4-hour battery site led at £6.3k for the month.
- The 4-hour batteries out-earned the 2-hour units 1.2× across the fleet this month (£16k → £19k).
- In the 4-hour battery configuration, bill savings added £172k across the fleet in July, on top of £19k earned in the markets.
- In the half-hourly data, London spot prices ran from £80 to £169/MWh on 30 July; the interval view shows how the batteries traded it.
About the model
These benchmarks are produced in Gridcog by simulating a fleet of identical reference sites against real market outcomes. Each monthly edition re-runs the fleet over the trailing 12 months of actual interval-level prices.
The reference site. Each region hosts the same logistics hub: an actual metered load profile of roughly 5 GWh a year with a peak demand around 1.1 MW, behind a 1.2 MW import / 250 kW export grid connection. The baseline scenario is just this load on a retail supply contract, and every other scenario is reported as value added against it. The solar scenario adds a 1.5 MW south-facing rooftop array (10 degree tilt), with yield derived from satellite-measured irradiance and weather at each site, time-aligned with the market prices; surplus solar is exported under a 5p/kWh Smart Export Guarantee. The storage scenarios then add a 1.2 MW battery in 2-hour (2.4 MWh) and 4-hour (4.8 MWh) configurations: 85% round-trip efficiency, 90% usable depth of discharge, capped at two cycles per day, with grid charging permitted.
Grid and network. The four sites sit in London (UK Power Networks), South Wales (National Grid Electricity Distribution), South Scotland (SP Energy Networks) and the North East (Northern Powergrid), each carrying its distributor's actual published site-specific DUoS tariff for a 1,200 kVA connection, plus regional TNUoS demand and residual charges and Triad peak-demand charges. We have deliberately used a mix of the network tariff classes that could apply to a site of this size (LV and HV, and different site-specific bands), so the fleet shows the range of network charging treatments a real portfolio would face, not just the spread in regional rates. The retail supply contract is fully pass-through: wholesale energy at peak and off-peak rates plus the standard GB policy and system cost stack (RO, CfD, FiT, BSUoS, CCL, Capacity Market, AAHEDC and supplier margin).
Markets and dispatch. The battery accesses wholesale prices behind the meter in the manner enabled by Elexon's P415 modification: it trades across the EPEX day-ahead half-hourly, day-ahead hourly and intraday continuous markets, with grid charging bought at wholesale and both grid-charged discharge and surplus solar sold at wholesale. On top of energy trading the battery stacks Static Firm Frequency Response (low-frequency service) at historical clearing prices and acceptance rates, and earns GB Capacity Market payments. Prices and weather are actuals from the same period, settled at interval level. Dispatch is co-optimised across energy, frequency response and the retail bill on a rolling daily horizon rather than with perfect foresight.
What's not included. No PPAs or hedges: energy is bought and sold at spot and pass-through retail rates. Figures are operating cashflows only, before capex, opex and financing. Balancing Mechanism participation is not modelled.
