Somewhere in your electricity costs is a set of charges you never chose: network charges banded by time of day, capacity charges fixed years ago, and a settlement system that increasingly prices every half hour of your consumption separately. If you run a half-hourly-metered site in the North East — a factory, a cold store, a depot — these lines are already on your bill, itemised or not. Manufacturing businesses averaged around 17–19p per kWh for imported electricity through 2025, but that average hides the point: the expensive hours cost far more than the cheap ones, and the expensive hours are the ones a battery can do something about.
This post is the longer version of one section of our commercial battery storage page: what peak shaving actually is, which charges it attacks, what has changed in the rules, and — because a battery is a real cost with a real working life — when it does not pay.
What peak shaving actually is
A peak-shaving battery watches your site’s demand and discharges when that demand — or its price — spikes, so the grid sees a flatter, cheaper profile than the one your building actually runs. The machines upstairs notice nothing. The meter notices everything. That is the whole trick, and everything else in this post is detail about where the money comes from.
The three charge lines it attacks
Time-banded network charges. Distribution Use of System charges — the cost of the wires themselves — are banded red, amber and green by time of day, and Northern Powergrid’s weekday late-afternoon red band is priced at a large multiple of the overnight green rate. A battery that discharges through the red band, every working day, cuts a cost line most businesses have never separately itemised. The exact band times and rates sit in Northern Powergrid’s charging statement, which is revised annually — we check the current one when we model a site, and so should anyone quoting you.
Capacity charges. A half-hourly-settled site pays for its agreed supply capacity — the kVA ceiling reserved for it — and exceeding that ceiling brings penal excess-capacity charges. A battery that caps your peak keeps a growing site inside its agreed capacity, which is sometimes the whole business case on its own: it can be the difference between adding EV chargers or new machinery this year and paying for a supply upgrade first.
The energy itself. Where your supply contract prices energy by time of day, shifting consumption out of the expensive windows is the third saving — and the one that pairs naturally with solar, since a roof generating at midday and a battery discharging at teatime between them cover most of a working day. What that pairing looks like for a North East roof is the solar page’s territory; the short version is that the two technologies each make the other’s case slightly better.
What has changed — and what the older articles get wrong
Two market shifts frame all of this, and one piece of received wisdom has quietly died.
The shift arriving first: Ofgem is moving every electricity meter in the market to half-hourly settlement under its market-wide programme. Businesses that never chose time-of-day exposure are getting it anyway, meter by meter — which means the profile your site runs will increasingly be the price you pay, and the value of controlling that profile rises accordingly.
The received wisdom that died: “Triad avoidance”. For years, battery articles promised big wins from dodging the three winter peak half-hours that set transmission charges. Ofgem’s Targeted Charging Review moved the residual part of those network charges into fixed banded charges — phased in through April 2022 and April 2023 — precisely so they could no longer be avoided by clever timing. Some of the older guides still online have not caught up. Honest modelling today builds the case on the red band, capacity and energy prices above, not on a charge that is now largely fixed whatever you do.
What the battery has to be, to do this job
Peak shaving is a power job before it is an energy job. The battery’s kilowatt rating decides how much load it can carry at once — it has to hold the site through the red band, not just contribute politely — and its kilowatt-hours decide how long it can keep that up. Get the first number wrong and the peak pokes through anyway; get the second wrong and the battery dies forty minutes before the band ends. Both numbers come out of your half-hourly data, which is why our sizing process starts there rather than at a brochure.
The control system matters as much as the cells. A peak-shaving battery has to know your tariff’s bands, watch site demand in real time, and still leave headroom for whatever else it does — storing solar surplus, holding a reserve for critical loads. We install Fox ESS systems across the commercial range, and run exactly this logic on them; the platform detail lives on our Fox ESS page, with every figure taken from the manufacturer’s datasheets.
When peak shaving does not pay
The honesty section, because a battery that does not earn its place is just capital in a cabinet.
- No time-of-day exposure yet. If your site is not half-hourly settled and your contract is flat-rate, the red-band saving does not exist for you today — though the settlement programme above means “today” has a shelf life.
- A flat or night-heavy profile. Peak shaving pays where demand spikes into expensive windows. A site that already runs flat, or runs mostly overnight on green-band rates, has little peak to shave — and we will say so.
- The battery’s own arithmetic. A commercial battery is working electronics with a working life of roughly 10–12 years, and daily cycling is what it will spend that life doing. The savings above have to clear the cost of the machine doing the work, including its eventual replacement — our modelling includes that, and any competing quote you compare should too.
The data that settles it
Three things tell us whether your site has a peak-shaving case: a recent bill, your half-hourly consumption data, and your agreed supply capacity figure. From those we can model the battery’s discharge against your actual profile and the current charging statement — not an average, not a brochure scenario — and show you the result either way. If the numbers say your site is one of the ones where storage does not earn its place, that is the answer you will get, with the working attached.
Send the bill, get the answer. Get a battery assessment or call 01388 662659 — and if you want the wider case for and against storage first, start with the commercial battery storage page.