Adding Battery Storage to a Solar PPA
Battery storage stacks well with PPA — but the contract drafting and revenue stack split are non-trivial. What the typical 2026 structure looks like.
Why batteries pair with PPAs
A bare solar PPA delivers kWh when the sun shines. Most off-takers consume some at peak times. Battery storage time-shifts surplus from midday to peak demand, increasing self-consumption from 60% to 80%+ — directly improving PPA economics.
How the deal is structured
Two main approaches:
- Bundled PPA + battery: single contract from PPA provider; tariff slightly higher to cover battery capex; provider owns battery for term.
- Separate ownership: off-taker owns battery (cash or asset finance) alongside PPA; provider operates only the solar.
Revenue stack with battery
- Solar PPA self-consumption (main saving)
- SEG export at off-peak (when battery full)
- Peak-shifting (avoid TNUoS / BSUoS peak charges)
- Frequency response services to National Grid (specialist)
- Capacity market revenues (Tier-1+ only)
Sizing the battery
Rule of thumb: 0.5-1 hour of system output. For a 500 kWp solar, that's 250-500 kWh of battery — enough to time-shift surplus into the 4-6pm peak.
Watch-outs
- Fire safety / ESS Class IV classification — insurance premium impact
- Cycle life — typical 6,000-10,000 cycles; 15-year useful life
- Round-trip efficiency 85-90% — accounts for ~£3-5k/yr losses on a 500 kWh battery
- DNO consent — some networks restrict export-side battery use
See what tariff your site qualifies for
A 60-second form gives us enough to match your site to providers and return an indicative tariff range within one working day.
Get an indicative PPA tariffBefore adding storage it is worth being able to model the solar side first, because storage mainly earns its keep by lifting self-consumption.
Batteries also make a private wire scheme more useful, storing a neighbouring generator's output until your site needs it.
Find out what tariff your site would be offered
Adding Battery Storage to a Solar PPA — tell us about your site and we'll return an indicative p/kWh tariff for it. Reply by email within one working day.