We learned from the Telegraph this week that 10 wind farms have each been paid ‘constraint payments’ of more than £3 million over the past three years to shut down their turbines, with one alone receiving £11 million. The reason for these payments is that generation and demand on an electricity network must be balanced from second to second. When demand is not sufficient to take up this generation, National Grid has to find a cost-effective way to reduce the electricity generated. They do this through constraint payments. As variable renewable generation such as wind and solar penetration increases from 18%, the need for these capacity services grows.