Opinion

A perfect day - the nightmare scenario: but UK's generation mix is working fine

Mark Whitby

Last Monday was a perfect day. But the blue sky heralded the nightmare scenario.

The high, as had been predicted, was accompanied by freezing weather and nationwide calm. As the sun rose so did the nation's demand for electricity, from the night-time low of 30GW to, by teatime, a peak of over 50GW.

The highest demand experienced in the last twelve months was met with an almost total silence from our wind turbines. This was the day the soothsayers had predicted that our grid should collapse.

But nothing happened; or rather quite a lot happened but nothing calamitous.

"Gas is clearly the friend of wind but as we see wind generation more than double over the next ten years we can expect to see the proportion of our energy generated from gas and coal to significantly decline."

Our gas generators stepped into the gap left by wind, upping their normal 15GW maximum to 20GW, our pumped storage followed suit with an unusually high 2GW contribution timed for the tea time peak, whist our hydro stations provide a steady half a Giga Watt.

Across the channel the French interconnector provided 2GW, they had 3GW coming in from Germany, so perhaps we should say it was the latter, and we took another 1GW from the Dutch via that interconnector.

Meanwhile coal provided a background load of 10GW rising to 15GW at the peak while our nuclear chugged away with an unrelenting 8.2GW.  

What you might ask does this tell us?

First the facts are there for anybody to see on www.gridwatch.templar.co.uk . What I noticed while following the story, is how the system is working, with gas generation now ‘man marking’ wind, backing off as it ups its game, and stepping in as wind backs off, going from the  peaks of 23GW at 6pm on Monday, Tuesday Wednesday and Thursday of last week to a low of 3GW on Friday night.

Gas is clearly the friend of wind but as we see wind generation more than double over the next ten years we can expect to see the proportion of our energy generated from gas and coal to significantly decline.

However all those stations that stepped into the gap will still be needed and perhaps a just a few more. Obviously we have a system that works in part due to falling demand, (between 2005 and 2011 electricity consumption fell by 12% / capita,  www.nesta.org.uk) as well as the new generation of gas turbines.

But our nuclear generators are ageing and the promised replacements still at least 10 to 15 years away.

We are obviously going to need a few more gas turbines to fill the gap the retiring nuclear leave. But whatever soothsayers said about grid instability is now history. 

Monday definitely was a perfect day.        

Mark Whitby is a director at Davies, McGuire + Whitby and a past president of the ICE