Q4 2017: 2017 in review

by Dr Iain Staffell – Imperial College London 

Britain’s power system once again enjoyed its greenest year, with 50% of electricity coming from low-carbon sources. 

2017 saw generation from fossil fuels fall by a tenth; driven down by lower demand and greater wind output (see Article 3). Even after the historic reductions in carbon emissions in 2016, the CO₂ from British electricity fell by another 12% in 2017 (see Article 5).

The share of fossil fuels has fallen from 80% to 50% since 2010, and with it the share of flexible, controllable capacity. Coal and gas produced just 140 TWh of Britain’s electricity last year, having fallen for seven consecutive years from 260 TWh in 2010. Nuclear, renewables and low-carbon imports together produced 139 TWh, and as Carbon Brief reported, the share of low-carbon generation rose to over 50% averaged over the year.¹

The chart below shows how the daily mix of generation varied through the year. After plummeting 60% in 2016, coal generation fell by a further quarter in 2017. Coal is now the preserve of the colder months when demand is over 35 GW. April saw the first ever full day with no coal generation, and across the year there were 618 hours that were coal-free. Solar power has become a major supplier during the summer months, with more electricity coming from the sun than from coal on 183 days last year.

Despite demand for electricity being highest during the winter months, this coincided with times when Britain was exporting electricity, primarily to France. With French nuclear reactors offline again during Quarter 4 for safety upgrades, France was willing to pay more for electricity and so our generators profited from exporting (see Article 6).

With more low-carbon capacity due to come online during 2018, the coming year may also see the majority of Britain’s power coming from low-carbon sources.

Daily average generation mix during 2017

1. This milestone includes the output from smaller generators which are ‘invisible’ to the electricity system. Some ‘captive’ power stations – or ‘autogenerators’ – are used to power industrial sites and never export electricity onto the national grid. No estimates of their half-hourly output exist, so they cannot be included in the Electric Insights data. ↩

Authors: Dr Iain Staffell, Professor Richard Green, Dr Rob Gross and Professor Tim Green.