Published 28 May 2026 · 8 min read

Ofgem's 13% Price Cap Rise from 1 July 2026: My Bill, the Maths, and Where Plug-In Solar Fits

Yesterday Ofgem confirmed a 13% rise in the energy price cap. I sat down with my own bill, did the sums in pounds and pence, and looked at how plug-in solar fits, including the other thing happening in July.

Update, 31 May 2026. When this piece was written on 28 May 2026 it described the DESNZ Interim Product Specification as a product spec that does not on its own change BS 1363 or BS 7671. Subsequent research shows the regulatory route was already in place. The UK Government press release of 24 March 2026 (gov.uk) committed to "update the G98 distribution code and wiring regulations BS 7671 to allow UK households to connect <800W plug-in solar panels to domestic mains sockets, without the need for an electrician and with tailored safety standards". BS 7671 A4 (published 15 April 2026) delivered the BS 7671 piece. The G98 piece is in Ofgem consultation Q3-Q4 2026 with effect in 2027. The Interim Product Specification (v2.0, July 2026), with SI 2026 No. 848 in force from 27 August 2026, is what makes the route practically usable. The piece below has not been rewritten beyond this note; the dated BSI 2026 Tracker carries the updated standards picture. Update, 15 September 2026. The G98 piece did not slip to 2027. Ofgem approved the G98 change (DCRP/MP/26/02) on 11 August 2026 and plug-in solar became legal on 27 August 2026 under SI 2026 No. 848. A kit that shows as Compliant on the ENA G98 Type Test Register may now be plugged into an ordinary 13A socket and self-notified to your network operator afterwards, with no electrician. A CPS-registered electrician and a hardwired connection are required only for a kit that is not on the register. one hundred and nine kits from twenty-four manufacturers are Compliant, 20 are on sale, and the cheapest is £336. Where the piece below says an electrician is required, read it as the position in May 2026.
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Adeniyi Adeniji, Founder of Plug Solar Hub
I track UK energy policy, prices and plug-in solar standards so households can make decisions on facts, not headlines. The numbers below are mine, on my own bill. If anything here is wrong, email me and I will correct it.
Published: 28 May 2026 · Last reviewed: 15 September 2026

I opened my last electricity statement and sat with the standing-charge line for longer than I would like to admit. Then on Wednesday 27 May 2026, Ofgem confirmed a 13% rise in the energy price cap for the period 1 July to 30 September 2026. That headline figure travels far. What it actually means in pounds and pence on one bill is a different conversation. This is mine.

By coincidence, the same summer brought another date that matters for anyone watching plug-in solar in the UK. The DESNZ Interim Product Specification was published on 16 July 2026, and the plug-in route became legal on 27 August 2026. The two are not connected. The timing is worth sitting with.

What Ofgem actually announced

The Ofgem release on 27 May 2026 covers the price cap for the period 1 July to 30 September 2026. The cap is the default tariff: the maximum unit rate and standing charge a supplier can bill if you are not on a fixed tariff. Around 40% of accounts (roughly 22 million) are on fixed tariffs and are not affected by this rise.

The numbers worth holding in mind:

+13%
Headline cap rise from 1 July
+5%
Electricity bill rise (typical)
+24%
Gas bill rise (typical)
£1,663
New typical annual bill (updated TDCV)

The driver, in Ofgem's words, is higher wholesale gas prices, linked to the ongoing conflict in the Middle East. The reason electricity is rising by less than gas is the one most under-reported in the news clippings: the share of renewable generation on the system has grown, so the grid leans less on gas to make electricity. The bill split reflects that.

One nuance on the £1,663 figure. Ofgem also published an updated Typical Domestic Consumption Review on 27 May. Households are using around 7% less electricity and 17% less gas than at the last review, so the "typical" basket against which the cap is measured has shrunk. The headline £1,663 a year uses the new TDCV. Under the old TDCV the typical bill from July would read £1,862.

My bill, in pounds and pence

To make this useful, here is exactly what I am paying right now. My tariff today, on the price cap:

  • Standing charge: 54.74p a day
  • Unit rate: 25.07p per kWh
  • April usage: 137.33 kWh

April was a quiet month. The heating was off, the long evenings had started, the dishwasher and the kettle did most of the talking. I am going to use April as a representative month for my own electricity use and work the numbers from there. Your own profile will be different, and that is the point of doing the maths in the open.

What April cost me on electricity

Standing charge, 30 days at 54.74p£16.42
Units, 137.33 kWh at 25.07p£34.43
April electricity total£50.85

If I roll that out across a full year, holding the daily standing charge across 365 days and assuming April is an average month for usage (1,647.96 kWh over the year), my electricity sits at roughly £612.94 a year on the current cap.

What the July rise actually does to that bill

Ofgem will publish the exact new unit rate and standing charge for each region. For the purposes of working out what the rise means for me today, I am applying the headline 5% electricity bill increase evenly across my unit rate and my standing charge. When Ofgem's detailed figures land, the split between the two could shift a little, but the totals tend to land in the same place.

On a flat 5% increase, my rates become:

  • Standing charge: 54.74p → 57.48p a day
  • Unit rate: 25.07p → 26.32p per kWh
Standing charge, 30 days at 57.48p£17.24
Units, 137.33 kWh at 26.32p£36.15
New April-equivalent total£53.39

So the increase, on me, looks like this:

+£2.54
A month, at April usage
+£30.50
A year, if held all year
~£643
My new annual electricity bill
95%
Of my bill is still here, unchanged
The honest reading. £2.54 a month sounds modest. On a winter month with the heating on, that same 5% applies to a much bigger usage, so the cash figure grows. And this rise stacks on top of every prior rise. The price cap is not a one-off event, it is the running cost of a structural exposure: the share of UK electricity that still gets made from gas, and the gas market is volatile.

Why electricity took the smaller hit this time

This is the part of the announcement I want to dwell on, because it carries the strategic message. Gas is rising 24%. Electricity is rising 5%. The gap is not random. Ofgem says, in plain language, that "this reflects the increase in the amount of renewable generation on the system and therefore reduced reliance on gas to generate our electricity."

The grid has been quietly de-risking. The more wind, solar and storage on the system, the less the electricity price has to follow the gas price. The 24% versus 5% split is the financial shape of that change.

That same shape works at household scale. Power you generate yourself on a balcony or wall is shielded from the part of the cap that moves. It does not solve the bill. It moves a fraction of your usage off the bit of the system that gets shaken by gas.

The other July date worth knowing

The DESNZ Interim Product Specification was published on 16 July 2026, and the plug-in route became legal on 27 August 2026. This is the certification side of the picture. For anyone watching the UK plug-in solar market, it was the most concrete milestone of the year.

I want to be precise about what it does and does not do, because it is the single most over-reported part of the topic.

  • What it is. A product specification: the UK benchmark that a plug-in solar kit must meet at the level of the equipment, things like inverter behaviour, anti-islanding, labelling, safety testing.
  • What changes in practice. Manufacturers selling into the UK will have a clear UK specification to test against. Retailers can verify a kit against a UK-recognised standard rather than relying on European VDE marks. Buyers can ask "is this BSI-listed" and get a real answer.
  • What I expected not to change, writing in May 2026. I read the product specification as something that would not, on its own, alter BS 1363 or BS 7671, and I expected a CPS-registered electrician and a hardwired connection to stay compulsory. That is not how it played out. SI 2026 No. 848 and the approved G98 change made the socket route lawful on 27 August 2026 for any kit listed as Compliant on the ENA G98 Type Test Register.
What I would and would not say about timing, in May 2026. I would not say plug-in solar via a 13A socket became "DIY-legal" in July 2026, and it did not. It became legal on 27 August 2026, when SI 2026 No. 848 and the approved G98 change took effect together. For the dated, primary-source view of where each document sits, the BSI 2026 Tracker is the page I keep updated.

What does happen, if BSI publishes as expected, is that the kit you buy in August 2026 can carry a clear UK product specification, and the install your CPS-registered electrician signs off can reference that specification on the certificate. That is a real, useful change. It is not the same as "you can plug it in", but it tightens the supply chain for everyone who buys a kit.

Where plug-in solar fits against a rising bill

Here is the part where I have to be careful not to oversell. Plug-in solar does not cancel a price rise. It chips a piece off the unit-rate side of your bill, on the same days the sun is out, in exchange for an up-front cost.

The yield maths, on a typical UK setup

A typical UK 800W plug-in solar kit on a south-facing balcony or wall generates somewhere between 600 and 700 kWh a year (PVGIS-modelled, varies by city and tilt). The economics depend on self-consumption: how much of that you use directly versus how much exports without payment, because most early UK kits do not yet pay export.

If I take 70% direct self-consumption as a realistic figure (running a fridge, freezer, router and a few daytime loads), the kit offsets between 420 and 490 kWh a year of grid electricity.

At my current unit rate (25.07p)~£105 to £123 a year
At the current cap unit rate (26.11p)~£110 to £128 a year
Across the next 10 years, if rates trend up£1,200+ avoided

The compliant install side, as it stands on 15 September 2026:

  • 800W kit listed as Compliant on the ENA G98 Type Test Register: from £336
  • CPS-registered electrician hardwiring and submitting G98, needed only for a kit that is not on the register: around £250 to £450
  • All-in compliant cost for a register-listed kit: from £432, because you plug it in and self-notify yourself

That puts simple payback at around three and a half years for a south-facing balcony on a register-listed kit, on pure self-consumption, at the current cap rate. The national modelled saving is £124 a year. If unit rates climb further over that window (and the structural argument above says they probably will), the payback shortens.

I am not selling plug-in solar as a silver bullet. I am saying that when the structural cost of electricity rises, anything you generate yourself becomes more valuable. The 5% on the unit rate is not what makes the case. The decade of rates above today's is what makes the case.

What I am doing about it personally

Three things, in order:

  1. Reviewing fixed tariffs. 40% of households are on fixed tariffs and are not affected by this rise. I am comparing what is available in my postcode against the price cap path Ofgem has laid out for July to September.
  2. Switching standard credit to direct debit if I have not already. Ofgem flags this in the release as worth around £143 a year on a typical bill. It is a small piece of admin with a real return.
  3. Sizing an 800W plug-in solar kit for my flat and buying from the register. The waiting is over: the specification was published on 16 July 2026 and the socket route became legal on 27 August 2026. There is no electrician to book for a kit that shows as Compliant on the ENA G98 Type Test Register, so the only check that matters now is that the kit is on it.

I bookmark the BSI 2026 Tracker for the standards picture, the calculator for the savings picture by postcode, and the Complete UK Guide for the long-form view.

Common questions

  • Not necessarily. The 13% headline is the cap rise across electricity and gas combined. On 27 May 2026 Ofgem said electricity is rising by around 5% and gas by around 24%. Your actual cash increase depends on how much electricity and gas you use. For an electricity-only example like mine, the rise is closer to 5% than to 13%.
  • Yes, if the kit shows as Compliant on the ENA G98 Type Test Register. The DESNZ Interim Product Specification v2.0 was published on 16 July 2026, Ofgem approved the G98 change (DCRP/MP/26/02) on 11 August 2026, and SI 2026 No. 848 made plug-in solar legal on 27 August 2026. A register-listed kit goes into an ordinary 13A socket and is self-notified to your network operator afterwards, with no electrician. A kit that is not on the register still needs a CPS-registered electrician and a hardwired connection.
  • A typical UK 800W kit generates around 600 to 700 kWh a year on a south-facing balcony or wall. With around 70% direct self-consumption you offset roughly 420 to 490 kWh. At the current price cap unit rate of 26.11p, rising to 26.32p on 1 October 2026, that is around £110 to £129 a year. The national modelled saving is £124 a year. The figure depends on location, orientation and how much you use during daylight hours. The postcode calculator gives a more specific estimate.
  • No, the waiting is over. The DESNZ Interim Product Specification v2.0 was published on 16 July 2026 and plug-in solar became legal on 27 August 2026. The one thing to check is the ENA G98 Type Test Register: one hundred and nine kits from twenty-four manufacturers show as Compliant, 20 are on sale, and the cheapest is £336. A kit that is not on the register cannot simply be plugged in.

Sources

If a source above moves or is updated, this post will be updated within seven days. Substantive corrections are logged on the changelog. Email me at [email protected] if you spot an error.

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Related reading: BSI 2026 Tracker · BS 7671 and Plug-In Solar · Complete UK Guide · Postcode Calculator · Why I chose plug-in solar as a London renter

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