The man in charge of Labour’s green energy dream: ‘It’s at the limit of what’s achievable’

Fintan Slye: ‘We’re not saying the target is achievable with the current ways of working. In fact, it’s not.’ Photograph: Suki Dhanda/The Observer

The dense latticework of Great Britain’s electricity grid looms above the control-room floor from giant digital screens that show every pulse of the country’s power system.

From this unassuming office block in the Berkshire countryside, home to National Grid’s control centre, the UK’s shift away from fossil fuels has been monitored for more than 30 years.