Sixth Carbon Budget Does Not Add Up!

By Paul Homewood


When I looked at the CCC’s Sixth Carbon Budget last December, I concentrated on costings.

However, given recent revelations about their wildly optimistic assumptions about wind power, I thought I would take closer look at their Power Sector calculations:



Let’s begin with their 2050 capacity scenarios. I’ll focus on the Balanced Pathway as the central case, though other scenarios demand even greater electrification:



If we work back from 2050, capacities in 2040 are projected to be:

Wind – 65 GW

Solar – 55 GW

Gas CCS – 5 GW

Nuclear – 10 GW

Total – 135 GW

It is planned that all unabated generation, ie gas and coal, ends in 2034.

But when we turn to demand, the CCC estimates 625 TWh pa:


This includes 58 TWh of electrolysis. Excluding this, the actual level of demand is 567 TWh. Assuming demand was constant throughout the year, that would imply a required capacity of 65 GW.

As we know however, demand for electricity is much higher during winter months, something which would be exacerbated by electrification of heating. Even assuming that storage could cope with day/night fluctuations, daily demand could easily average 85 GW in winter. And after allowing for de-rating, that is to cover generating plants being offline at times, the grid would need at least 100 GW to cope.

But according to the CCC’s scenario, we would only have 15 GW of dispatchable power, ie nuclear and gas. They do say that interconnector capacity could rise from the current 6 GW to 18 GW, but this will only make a dent in the amounts needed, even if could guarantee it.

If that was not bad enough, even with 18 GW of interconnectors, we would still need about 70 GW from the 120 GW of wind and solar capacity. Even at average levels, they will produce nothing like this, maybe about 40 GW.

In particular, solar power typically runs at less than 5% of capacity in winter, equivalent to 2 GW. An utter irrelevance in other words. To meet demand of 85 GW, therefore, wind power would have to supply 50 GW, even with interconnectors, gas and nuclear working flat out. But on most days, wind power will running at much less than that, given total capacity of 65 GW.

As for storage, the CCC is banking on hydrogen burnt in converted gas plants, produced from surplus wind power, as the primary source, but the amounts will be tiny, just 20 TWh by 2035. This will only be of use for meeting peak demands for an hour or so each day.

They talk of up to 25 GW of battery and pumped storage, but that would only amount to about 25 GWh or so. Daily demand in winter would be around 2000 GWh, so again this storage would only be of use for a few minutes a day. Remember as well that they have to be recharged at other times during the day, at a time when electricity may already be in short supply.

There is clearly an enormous capacity gap here, not to mention a credibility gap! Yet the CCC report does not even seem to be aware of it. Indeed, this is the only mention I can find where they address the issue:


We are sleep walking into a disaster, led by the CCC who seem oblivious of the fact.


October 27, 2021 at 11:03AM

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