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.