From 1,000 kVA to 70 kVA.
How a review of 24 months of maximum-demand data led to a major reduction in Authorised Supply Capacity for an anonymised UK manufacturing business.
The reserved capacity had moved a long way from the site's actual demand.
This was not a supplier unit-rate exercise. The issue sat in the network charging structure: the site was carrying 1,000 kVA of Authorised Supply Capacity while its recorded demand was materially lower.
We asked the DNO for the underlying data.
Smart Energy requested the previous 24 months of maximum-demand figures, the current authorised capacity, the site's HV/LV status and confirmation that the correct Line Loss Factor tariff was being applied.
The supply was confirmed as HV.
SP Energy Networks returned the demand and capacity history and confirmed that the site was already on the lowest applicable HV LLF/tariff. That meant there was no lower LLF band to pursue.
The ASC rose sharply while the site's demand stayed low.
The DNO data showed 100 kVA of authorised capacity in June and July 2024, 500 kVA from August 2024, then 1,000 kVA from May 2025. The month the ASC moved to 1,000 kVA, recorded maximum demand was just 29 kVA. Across the final 12 months reviewed, monthly maximum demand averaged 29.2 kVA and never exceeded 41 kVA.
A reduction to 70 kVA was requested.
After reviewing the demand pattern and the client's position, Smart Energy asked the DNO to reduce the Authorised Supply Capacity to 70 kVA. The DNO approved and processed the change.
The recent demand profile was nowhere near 1,000 kVA.
The full 24-month record included one higher reading of 84 kVA in November 2024, followed by 60 kVA in December 2024. From January 2025 through May 2026 — 17 consecutive monthly readings — maximum demand never exceeded 41 kVA. Over the final 12 months reviewed, the monthly maximum averaged 29.2 kVA against an ASC of 1,000 kVA.
From enquiry to approval.
The case moved quickly because the request went directly to the network operator with a valid Letter of Authority and a specific set of technical questions.
Smart Energy requested the capacity and demand history.
The request covered 24 months of maximum demand, current ASC, connection level and whether the LLF classification could be improved.
SP Energy Networks returned the data.
The DNO confirmed the HV supply, supplied the demand/capacity history and confirmed the customer was already on the lowest possible applicable HV tariff.
Smart Energy requested 70 kVA.
The reduction request was made directly back to the DNO after reviewing the returned capacity and maximum-demand information.
The reduction was approved and processed.
SP Energy Networks confirmed the new Authorised Supply Capacity at 70 kVA, effective from 1 June 2026, and advised that the supplier would also be informed.
£33,945 a year — with the calculation shown.
The DNO confirmed the physical change in capacity. The financial saving is Smart Energy's annualised calculation using the capacity charge applying to the client's account when the review was completed.
A network cost issue that would not have been solved by simply finding a cheaper supplier.
The case shows why a commercial electricity review can need to go beyond unit rates and standing charges. The site's network capacity had to be checked against real demand before the saving could be identified.
The 70 kVA figure was below the single 84 kVA reading recorded in November 2024, but the subsequent demand profile was materially lower: no monthly maximum exceeded 41 kVA from January 2025 through May 2026. That more recent operating pattern formed part of the review before the 70 kVA request was made and approved.
SP Energy Networks also warned that surrendered capacity may not automatically be available again in future and could require network reinforcement and associated costs. Capacity reductions therefore need to be considered against the site's future operational requirements, not treated as an automatic exercise.
That distinction matters. Procurement is one part of commercial energy management; metering, network charges and site configuration can create costs that supplier-price comparisons alone will never find.
The client's identity, MPAN, contact details and precise site information have been withheld for commercial confidentiality. Technical figures are taken from the completed review and DNO correspondence. The £33,945 figure is an annualised calculation based on the capacity charge applying when the review was completed; it is not a supplier or DNO guarantee of future charges.
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