Guy Faulkner

Great Britain’s electricity generation from wind has steadily increased over the past three years but Gridwatch statistics highlight the intermittency problem faced by engineers operating the electricity grid. While around 800 Gigawatts (GW) per quarter are generated in the winter period, only around 500GW are generated in the summer quarters.

Daily fluctuations can be extreme. On good days for wind, 10 Gigawatts or more can be generated and typically around 500GW are produced in this way in the winter quarters. In January-October this year, daily output was in this category on 62 days (20.4%) compared with 102 days (27.9%) in the 2022 calendar year and 57 days (15.6%) in 2021.

There are however many days in which output is below 5GW and less than 100GW are contributed in the winter quarters when there is little wind. Last year 36.7% of days were in this category, rising to 44% in January-October this year. In 2021, almost 50% of daily output was below 5GW.

It can be seen from the charts below that usually the most common category for wind generation is between 5GW and 10GW. There is little seasonal variation in this and Gridwatch statistics show that quarterly output in this category is usually 200-300GW.

The need for backup – mainly from gas-fired power stations – is illustrated by the daily figures. In January of this year, wind output was in excess of 10GW on 13 consecutive days, peaking at 16.2GW on January 11. But output then fell before rising again briefly at the end of the month. There was only one day in January-March when wind output fell below 2GW.

In July-September of this year, output was below 5GW on 43 days (46.7%). It was less than 2GW on 12 days and there were even two days when output was less than 1GW. There were only 7 days with output below 5GW in October of this year.

The April-June quarter this year was particularly poor for wind, with only 5 days (5.5%) in which output exceeded 10GW. This compared with 14 days (15.4%) in April-June last year, although only 4 days fell into this category in April-June 2021. Daily output was below 5GW this year in April-June on 58 days (almost 64%).

Nowhere has it been shown that an industrial economy can operate using wind and solar for electricity generation and these figures illustrate why this is. The contrast between wind and nuclear power generation could not be more stark and renewable power is given priority so that gas-fired power stations have to be kept ticking over to be called into action to ensure that electricity demand is met. This is very inefficient. Every new wind turbine erected presents a grid manager with a problem, not a solution.