UK power supply quality decreases as renewable supply increases

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As the proportion of renewable electricity and, in particular, less predictable forms of electricity generation increases, maintaining the quality of the UK’s electricity supply is becoming more difficult.

The power distribution system in the UK is based on a frequency of 50Hz with any major change from this causing a drop in quality of supply or even, in the worst case, potential power cuts. Referencing the European Network of Transmission System Operators for Electricity (Entsoe), the Reuters’ report says the growth in renewable electricity across Europe has coincided with a drop in the quality of power. It warns that in the event of low renewables output together with a large failure of capacity would present a “a severe risk for the system to collapse.” The press report also quotes the UK’s National Grid Companies’ electricity ten year statement as saying: “The reduction in fault levels weakens the overall strength of the network which in turn can give rise to quality of supply issues such as large voltage steps, harmonics and flicker.”

The issue does not seem to be the overall reliability of renewable capacity now providing power to the UK’s electricity grid. Instead it’s how the different generation types, particularly with a variable output, are integrated into the supply system without causing frequency changes. A decade ago the UK had very little renewable capacity, relying almost entirely on fossil fuel and nuclear powered generation; we now generate around 10% of our electricity from renewable sources.

Some of the approaches to counter frequency problems range from small but rapid electricity supply adjustments to large scale emergency backup generation. Another approach involves the UK developing electricity storage technology, particularly through OfGEMS Low Carbon Network Programme. UK Power Networks have recently won £13.2m to develop a 6MW electricity storage project to investigate the economics of the technology.

For more information, help or advice please contact Andrew Davison on 0191 211 7950.