Much greater flexibility needs to be built into the power system to ensure energy security and avoid spiralling costs, according to a new report.

In an update to its 2006 systematic review, the UK Energy Research Centre (ERC) said that costs will be much higher than they need to be if “intermittent” sources of generation – such as wind and solar – are added to the system without increasingly flexibility.

When the initial report was published, the main finding was that the cost of integrating renewables into the power grid is modest – but the original report’s authors did not consider variable renewable penetration levels above 20%.

Since then, targets for renewable energy have increased significantly in many countries, and a substantial proportion of these targets will now be met through the large scale deployment of renewables, the updated study found.

Flexibility not capacity

Phil Heptonstall, lead author of the report, said: “The findings reveal that the costs of intermittency lie within a wide potential range, and that it is no longer possible to estimate system costs simplistically, for example by adding up the cost estimates for individual categories of impact together.”

Rob Gross, co-author of the report, added: “The conversation we have every winter, which is only about whether we have enough spare capacity to keep the lights from going out, is the wrong question.

“What we should be asking instead is not just how many power stations we need, but whether they’re the right kind of power stations to keep the system flexible enough.”

> Download the report