Policy & Grants  ·  Issue 3  ·  Tuesday 16 June 2026

Watts Happening

 

The UK energy newsletter that doesn't work for the industry

The Spark

The April price cap fell. The cost of connecting your home to the national grid went up 65%.

When the cap changed on 1 April, the coverage was broadly positive. Bills down, pressure easing, Ofgem doing its job. What didn't make the headlines was what happened inside the standing charge at exactly the same moment.

The transmission element of your electricity standing charge, the portion that funds the high-voltage national network rather than the local wires, rose by almost 9p a day in Q2. A 65% increase in a single component, in a single quarter, to fund a major capital expansion by the National Energy System Operator. It was in the Ofgem annexes. It was not in the press release.

Ofgem also moved Warm Home Discount costs off standing charges onto unit rates from April. That saved the average dual-fuel customer 4p a day on their standing charge and generated most of the positive coverage. The transmission rise cost more than twice that, running in the opposite direction, on the same bill in the same month. The net movement in standing charges was upward. Most people who felt relieved about April haven't looked at both numbers together.

This Week in Watts

Wales made rooftop solar a legal requirement. England is two years behind. Here's what it means for anything you own, build, or plan to renovate.

From 4 March 2027, virtually every new building in Wales needs an on-site renewable electricity generation system as a functional requirement of building control approval. House, office, warehouse, retail unit. Solar panels aren't named in the statutory text but they are the only practical way to comply for the overwhelming majority of buildings. This isn't a grant scheme or a planning condition that gets negotiated away over pre-application meetings. It is the law, and building control won't sign off without it.

A year later, in March 2028, the requirement extends beyond new builds to existing buildings undergoing works that need building control approval. A full re-roof. A structural renovation. A material change of use. If you are converting a commercial unit to residential after that date, solar comes with it whether it was in your original budget or not.

The figures behind the mandate are clear. The Welsh Government's chosen standard delivers a 93% reduction in carbon emissions over the previous Part L baseline. The cost is an average capital uplift of £5,123 per dwelling, which is 3.3% on top of build cost. That is the compliance price. The other side of that number is a building with lower running costs structurally locked in from day one, which matters increasingly in a market where energy performance is being priced into asset values whether owners are ready for it or not.

Two exemptions exist. If the roof cannot physically accommodate a system capable of generating at least 720 kWh per year, roughly a fifth of a standard 3.5kW residential array, the requirement does not apply. The same is true if the design or surroundings make a viable installation impossible, significant shading being the most common example. Everyone else builds with solar or does not get sign-off.

England, for comparison, enacted its Future Homes Standard on 24 March 2026. New homes must meet it from 2028, with solar and clean heating as a functional requirement. Wales set an earlier deadline, extended the scope to renovations as well as new builds, and did it a year ahead. The gap between what the two nations now require of their built environment is not a rounding error.

For anyone holding land or property with development potential in Wales, the appraisal mathematics changed the day those regulations came into force. Solar is no longer a line item you add to improve the EPC or soften a planning objection. It is a baseline cost of construction. The time to factor it in was before you agreed the land price. The second best time is now.

A mandate that adds £5,123 to build cost adds the same figure to the floor price of every compliant asset that follows.

The Bill Buster

One date. One conversation with your architect. Potentially five figures saved.

If you have planning permission for a development in Wales and construction has not started, the date that matters is 4 March 2027.

Break ground before that date and you build under the current rules, with no mandatory solar requirement. Miss it and the new regulations apply automatically, with an average £5,123 capital uplift per dwelling folded into your compliance obligation from the first brick. On a ten-unit scheme that is £51,230 in costs that were not in your original numbers.

Most planning permissions run for three to five years, though yours will state the expiry date explicitly. A permission granted in late 2022 or early 2023 could be approaching expiry right around the time the mandate kicks in. The question worth asking your architect or planning consultant this week is straightforward. When does my permission expire, and can I demonstrably commence construction before 4 March 2027?

In planning terms, commencement generally means material operations have begun on site, foundations dug and groundworks underway, rather than the build being finished or substantially complete. That is the legal threshold that fixes which set of regulations governs the build. If there is any realistic risk of slipping past March 2027, that conversation needs to happen before Christmas, not after.

→ Pull your planning permission this week and check the expiry date against 4 March 2027

Watts on the Market

Unsold this week  ·  Reader resource

If you have read this far, you already think about energy costs differently to most people. The question most people never actually answer is what staying as you are costs over time.

The Watts Happening Cost of Inaction Calculator runs your current energy setup forward 25 years. Your bill size, your property type, two inflation scenarios. No installer waiting at the end of it. No upsell. Just the number that most energy conversations quietly avoid.

→ Run your 25-year energy cost at wattshappening.energy

Quick Watts

Standing charge pilot
Ofgem launched a lower standing charge tariff pilot in April 2026, running for one year across EDF, E.ON, Octopus, and British Gas. It is aimed at low-usage customers. Full eligibility criteria have not been published. If you are with one of those four suppliers and your consumption sits well below average, it is worth a call to ask whether you qualify.
(Ofgem, April 2026)
Warm Home Discount shift
From April 2026, 80% of Warm Home Discount costs moved from standing charges to unit rates, cutting the average standing charge by 4p a day. The practical effect runs in reverse for low-usage households: your standing charge fell slightly, but your unit rate went up. The shift benefits high-consumption homes more than low-consumption ones.
(House of Commons Library, CBP-10339)
Future Homes Standard
The Future Homes Standard was formally enacted in England on 24 March 2026. New homes must comply from 2028, with solar panels and clean heating as a functional requirement. Wales mandates solar from March 2027 and extends to renovations from March 2028. England's standard covers new builds only.
(GOV.UK, 24 March 2026)
Welsh solar law in force
The Building etc. (Amendment) (Wales) Regulations 2026 are now active under circular WGC 003/2026. The Solar Energy UK summary and the statutory instrument are the primary references for compliance queries.
(Solar Energy UK, March 2026)

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