 Plummeting temperatures have forced National Grids electricity system operator ESO to request the warming up of three coal-fired power stations to help keep energy supplies secure. Meanwhile, a blackout-swerving scheme that pays households to limit consumption during peak hours is also being launched tonight. As the cold snap plunged Britain into subzero temperatures on Sunday, National Grid ESO ordered ... Energy supply will be tighter tonight but Brits can be paid to... 