A recent industry study into the UK energy sector of 2030 - which according to government plans will use a hugely increased amount of wind power - suggests that massive electricity price rises will be required, and some form of additional government action in order to avoid power cuts. This could have a negative impact on plans for electrification of transport and domestic energy use.
The study is called Impact of Intermittency, and was carried out by consulting group Pöyry for various industry players such as the National Grid and Centrica at a cost of more than £1m. Pöyry modelled the likely effects on the UK electricity market of a large windpower base of the sort needed to meet government carbon targets - assuming no major change in the amount of nuclear power available.
There's a summary of the report for the public available here in pdf - probably quite detailed enough for most of us at 30 pages. It says that there's no particular problem for the National Grid as such - the actual electricity transmission network - with large amounts of wind in the 40+ gigawatt capacity range. But the introduction of so many wind turbines will spell disastrous problems for operators of "thermal" plant - that is fossil fuelled, and conceivably nuclear too.
According to James Cox, one of the report's authors: "Our worry at the outset of the study that the very dynamics of variable wind output would challenge the system operators, has moved to concern that the economic environment for thermal plant will be highly challenging.”
Massive unpredictable variations in the amount of energy coming from the wind would combine with the much more regular changes in demand and in possible tidal power projects to produce an energy market described in the study as "volatile". If there were enough thermal plants in existence to cope with rare (but nonetheless certain to occur) events such as nationwide calms during winter evenings, some of these plants would almost never be in use. They'd sometimes go years without running for more than a few hours.
In order for energy companies to build those thermal plants, necessary to avoid power cuts, they'd need to be sure that they could charge enormous, outrageous prices during the brief periods when they were actually in operation. According to the report's authors:
In our opinion, it is likely that the sort of price 'spikes' needed to reward the risks for such plant will stretch the market design to its utmost... Equally a market with spiky and volatile prices is one where the risk of operation is greatly increased: it is unlikely to send clear economic signals to new investors.
In other words, nobody would want to build and maintain a power station with no reliable idea how much it would get used from one year to the next (the report reveals that the UK's annual wind output could be expected to vary by no less than 13 per cent). A certainty of enormous rewards when the kit was finally needed would be required in investors' minds - but there could be no such certainty. The spot electricity price would need to soar to such levels as to introduce even more risk, in the form of government intervention to protect energy distributors from going bust and consumers suffering from vicious price surges.
As things stand, then, it will be more or less impossible to get the necessary contingency plants built - nobody would provide the capital for them. Thus, when the inevitable early-evening winter calms hit in the 2030s, the required amount of thermal backup power stations will simply not be there. Up to a certain point the National Grid can "manage demand" without causing power cuts by fiddling with the supply voltage, so delivering less power to users without cutting any of them off, but it has been known to crash right through this safety net even with the comparatively manageable power stations of today.
So we're talking power cuts on a fairly routine basis, if nothing else changes and the planned levels of wind farms appear.