The big picture
Hugh explains, “Despite efforts to go green with wind, solar, tidal and wave, the UK still relies heavily on burning coal. More than a third of our electricity comes from coal-fired power plants, with gas-fired power stations generating 27 per cent and nuclear reactors accounting for 20 per cent. Renewables fluctuate up to just over 14 per cent.
How it works
“People perhaps don’t realise how the demand on the UK grid fluctuates a lot over a typical day, and has very high peaks on a cold winter’s evening. The UK’s ‘operating margin’ - the gap between peak demand and peak generating capacity- is shrinking as 25 per cent of the UK’s power plant fleet are due to shut down in the next ten years. I’m not predicting blackouts this winter but according to a recent report by the National Grid the margin is down from around 11 per cent a few years ago to about 6 per cent now.
‘We won’t be left in the dark but we will be hit in the wallet…’
”It’s quite basic really – the National Grid and the overall system doesn’t store much electricity, it’s supplied almost ‘just in time’. So on a windless winter’s night when everyone has their oven on at home and factories are running a night shift, the Grid does two things –calls on the small reserves it has, and switches on extra generation which was on standby. This last piece is a very expensive option for them.
How this affects us
“We won’t be left in the dark but we will be hit in the wallet. The cost of building new generation capacity and the infrastructure for it (local networks need upgrading too) is projected to be £110 billion by 2020, and it takes a long time to build new power plants. There is no magic pot - every penny of that ultimately comes from either our power bills or our tax bill.
“Wind and solar are tipping ever more electricity into the system – solar went from zero in 2011 to a peak of 14 per cent of the UK’s generation capacity at times this year – but of course they generate intermittently. Bursts from what’s called hydro storage – man-made lakes at the top of a hill, released downhill to spin turbines for a few hours - are great because a lot of power is released within minutes. They have had some in the system for decades but there are very few suitable sites available to build more at the scale we need.
“Given all this, building UK electricity storage makes huge sense. Batteries, big and small, near generation sites and even in domestic houses, would collectively store power - this could be from solar panels in the daytime, or from the grid at 3am – and release it at peak times. Some large consumers could even look into building their own battery.
“The issue certainly dominated a recent solar-industry event in the UK, with everyone from SSE to DECC agreeing that more batteries are a great idea. SSE is of course fairly active here with pilot battery schemes in place both at domestic and medium scale, including some key learnings from the Shetland Islands.
“Ray Noble, an advisor to the UK’s Department of Energy and Climate Change (DECC) and National Solar Centre (NSC) said: "DECC thought storage was 10 to 20 years away, but technology has moved faster than anticipated with the battery cost curve today being similar to the solar PV's cost curve about three years ago".
“DNO’s (Distribution Network Operators) win because battery storage systems help manage technical challenges like voltage control, smooth the power quality and shape electricity generation to power demand. Having batteries is a cheaper solution than things like grid reinforcement. Other players win too: renewable energy operators can charge higher prices if they can mitigate the intermittency issue, and ultimately the UK consumer wins because all energy industry funds come from consumers and taxpayers.”
Hugh concludes: ‘’The whole system is changing, and it has to if we’re going to meet our carbon targets. As most experts say, we need it all – cleaner centralised generation, local power generation from renewables, energy-efficiency technologies in homes and businesses, and storage – it’s a logical move. It’s not exactly easy, but it’s easier than the alternatives, and I believe batteries stand to save us all billions in the long run.’’