Carbon Commentary

As of June 2026, Great Britain has about 10 gigawatts of grid battery capacity, capable of delivering about 18 gigawatt hours of power.[1] In addition, four pumped hydro sites offer storage around 24 GWh. That’s enough to meet total national demand for about an hour. The 16 new longer duration storage sites identified last week as ready for approval by the regulator Ofgem have a power output totalling 7.6 GW, or much less than today’s short duration battery park.

Heidelberg does not appear to dispute the newspaper analysis but has yet to admit the failure, presumably because it is in negotiation with several other governments over support for other CCS projects. The company’s various web sites all still continue to claim that Brevik is successfully capturing 400,000 tonnes a year and make no mention of the reasons why performance has fallen significantly short.

In the long list of new technologies that might help reduce carbon emissions ‘plug-in solar’ sits towards the bottom. A small array of PV panels perched on the garage roof, or perhaps fixed to the railings of a balcony or laid on supports in the garden, and then directly connected into an ordinary plug in the wall, is never going to make a major difference to the course of climate change.

The analyst Ben James provides very useful data on the composition of energy costs at www.electricitybills.uk. He calculates how a bill is made up for a household consuming 3,100 kWh a year, showing how much arises from the wholesale cost of electricity and how much from other elements, such as supplier costs, transmission and from the impact of government initiatives.[1] We are locked in debate as to why electricity prices are so high and rising in the UK.

When wind and solar provide more than 55% of GB electricity, imports of power from other countries start to drop sharply. Below this level of renewables generation we usually see over 5 GW of electricity from interconnectors but when the level gets above 75% the volume is typically less than 1GW.

The first winter storm of 2025 has just passed over the UK, providing huge amounts of wind-generated electricity. This wasn’t the first time in recent weeks. From late July to late August 2025 we saw a consistent mixture of high winds and good sun across the UK. At the peak at about 11am on the 11th of September, these renewable sources provided more than 27.5 GW into the GB electricity grid amounting to approximately 70% of total needs.

The journalist Andrew Neil published an article on 27th August about offshore wind in the Daily Mail, a UK newspaper. The article contains a large number of factual inaccuracies. I have commented on these in 15 notes in the text below. These points are are embedded below and to the right of the relevant sentences in the Andrew Neil text (which is now all in a bold font).

We still hear assertions that adding renewables to the grid has increased the UK’s electricity costs. I looked at two sources of data and plotted one against the other to test whether there’s any truth in this. 1,      The ‘next day’ electricity price for each hour in the period from 1st January 2025 to the early days of August 2025.[1] That’s about 220 days, covering the coldest period of the year and the heat of the summer.

If the government achieves its targets for renewable electricity capacity for 2030, will it meet its objective for virtually decarbonising the GB grid? Other calculations are more optimistic but this note suggests that in all probability the answer is no. I looked at the last year (May 2025 to end April 2025) and multiplied the output of solar and wind generators in each half hour period to reflect the proposed increase in capacity and possible improvements in yield per megawatt of capacity.

Abstract This article takes data surrounding last week’s announcement of the first SMR farm in Ontario, Canada to assess whether this new approach to nuclear shows any signs of reducing costs below the level of larger reactors and renewable generators. In brief, the conclusion is that it does not. SMRs A small number of experimental SMRs have been built or are under construction in Russia, China and Argentina.[1] The history of these reactors has been full of delays and huge cost overruns.