The UK Chancellor George Osborne recently succeeded in getting a scenario into the UK government’s gas strategy. This involved having up to 48 GW of gas capacity in the UK by 2030. It is my view that this amount of gas capacity is, under any realistic scenario, more gas capacity than is consistent with decarbonising electricity by 2030. This view, it would appear, is also held by Greenpeace.
However, let’s consider how much gas capacity Greenpeace wants. Or, more importantly, how much gas capacity we would need if Greenpeace got what they wanted in terms of renewable energy.
To avoid any suggestion that I am cherry picking evidence let us begin by considering a recent report commissioned by Greenpeace and WWF into the economics of offshore wind and gas. The Wind scenario in this report actually required a total of 36 GW of gas capacity to back up wind. So, at this point we can say that what Osborne and what Greenpeace wants differ by about most 12 GW.
However, as Clive Bates pointed out, the n-word is suspiciously absent from this report. The Wind scenario actually appears to be identical to the “very high renewables” scenario considered by the CCC. This scenario is shown below.
Now, I don’t think I would pushing things out to suggest that Greenpeace do not want that much power coming from nuclear, or CCS for that matter. Put simply Greenpeace will want to replace all of this nuclear generation with renewables of some sort. So, how much nuclear are we talking about here. The CCC says of this scenario (see page 76):
To decarbonise to 50 g/kWh this scenario would still require around 12.5 GW of new nuclear and CCS capacity during the 2020s, in addition to the 5 GW added by 2020.
What is the consequence of replacing 17 GW of nuclear with some form of renewable energy? More gas plants as back up. How many? To get a rough idea let’s look at some modelling done by Poyry for the CCC. Below is the energy mix under different levels of renewable power.
So, a good ballpark estimate is that for every 8 GW of nuclear you replace with renewables you need about 5 GW of gas back up. Replacing 17 GW of nuclear with wind is therefore going to require about an extra 10 GW of gas capacity for back up.
Add this to 36 GW, and suddenly we are up around 46 GW of gas capacity. The difference between this and the amount of gas capacity George Osborne wants would appear rather negligible to me.
Now, my analysis above may or not be right. However, before Greenpeace claims George Osborne’s plans will bust the UK’s carbon targets they must first explain how the UK can decarbonise with their preferred level of renewables and without Osbornesque numbers of gas plants