Wind Dips below 7% of GB Power Mix

Wind-generated electricity accounted for 6.5% of Great Britain's 44 GW of power supply at time of press January 7, as the cold spell continued. This was even less than coal's 7.8%. Combined-cycle gas turbines contributed just over half (51.9%), nuclear 13.3% and biomass 6.9%. Other sources shown on the Gridwatch website included imports from the continent. The percentages will change over the day depending on the weather conditions. 

The country's reserve of spare capacity was low enough for the operator National Grid to issue a warning for the evening January 6, encouraging generators to ramp up, and major industrial users to consider turning down their offtake if they were contracted to do so.

Energy trader Hartree Solutions had warned the day before that Grid "will need to be issuing alerts, warnings and utilising many – if not all – of their balancing tools on Wednesday to keep the lights on.” But there were no power outages. Grid last issued a wind-related warning in November.

It is cheaper to pay expensive capacity prices and demand-side reduction contracts to cover these relatively infrequent and brief periods of calm air than to build new, although most generating plant works more reliably when it is in "steady state". The payments ultimately come from consumers' bills and the mechanism is overseen by regulator Ofgem, to encourage value for money.

The problems of intermittency are expected to grow as more wind generation capacity is added to the grid in the coming years. Coal-fired generation is to be taken off the grid by 2025.

UK gas demand was running at a projected 452mn m³/d at time of press, of which 310mn m³/d are for the low-pressure networks and power stations another 103mn m³. Exports through the interconnectors were projected at 38mn m³/d and industrial demand at 10mn m³/d. Northern Ireland is excluded from the statistics, hence the use of 'GB' rather than 'UK'.