UK electricity pylon and wind turbines

How do we stop renewables failing us again?

Image credit: Alpegor/Dreamstime

A UK energy supply regime that ensures security of supply at the same time as working towards net zero targets and coping with increasing input from renewables will need less input from politicians and more from experienced professional engineers.

In recent weeks the UK government under new prime minister Liz Truss has confirmed that it will endeavour to urgently address energy continuity challenges both within the UK and across Europe.

In doing so, it will be required to embrace critical issues that are rarely highlighted which face any long-term strategy to ensure security of supply across the UK; this all concurrent with achieving net-zero carbon emissions by 2050.

The latest government policy embraces the objectives of having 24GWe of nuclear generation by 2050 (by 2030 we can expect to have only the existing Sizewell B at 1.2GWe and the new Hinkley Point C at 3.2GWe) under a new nuclear directive body; quickly granting around a hundred new licences for extraction of gas and oil in the North Sea, and removing the current moratorium on fracking.

How secure and stable a supply have we created following privatisation some 30 years ago?

Most people will be unaware that during this summer’s UK heatwave, National Grid ESO (Electricity System Operator) was faced with a serious scarcity of available generating capacity. On July 18, it calculated a loss of load probability of 70 per cent, representing a seriously high expectation of shutdowns and disconnections being needed to balance demand and supply. This in midsummer.

National Grid did subsequently advise that a system constraint - a fire local to overhead grid lines in the London area - was a factor rather than inadequate capacity- but ‘scarcity’ did seem to exist alongside the ‘constraint’.

Several issues coalesced to create the crisis. Published figures for total European offshore wind generation in the period July 17-19, the peak of the heatwave, show it was providing a maximum of only 1.4 per cent of EU demand. From August 6-12 inclusive, this output varied from 0.3 per cent to a one-day high of 1.2 per cent with the remaining days not rising above 0.8 per cent.

At 0.3 per cent, total output was 25GWh. Compare this with October 5 at 5.1 per cent and 404 GWh of generation. Torness power station output is 1.2GWe and 28.8GWh/day at full power. North Sea wind output had dropped in comparison, therefore, to this week by the equivalent of 13 nuclear power stations.

These data seriously question the dependability of wind and the wisdom of pursuing it as long-term policy.

‘UK Balancing Mechanism Reports’ indicate that, coincidentally, 12,300 MWe of conventional generation (equivalent to the output of ten Torness power stations) was unavailable to the grid due to “planned maintenance”. Maintenance is usually scheduled in summer as demand is lower and electricity selling rates are also lower, which is convenient and appealing to generators to minimise income sacrifice.

Solar panel efficiency slumps in very hot weather by up to around 10 per cent as the ability of incoming light photons to excite electrons declines. The remaining thermal stations’ efficiency would also have fallen in the hot weather by several per cent. Power lines and transformer efficiencies would be lower, too.

National Grid ESO operates a continuously open on-line auction from its national control centre, one hour ahead of real-time to monitor and buy electricity. Short-term supply bid prices are selected for 30-minute periods to keep the UK system in balance.

Today, with high levels of unpredictable renewables, National Grid ESO acknowledges that “balancing services regularly exceed 50 per cent of national demand. For reference, the average was just 5 per cent in 2012”. This illustrates how dependent the UK is on others, mostly in Europe, to keep the country running.

Between September and November 2021 it was reported that the balancing mechanism cost had jumped to £967m from the £337m for the same period in the previous year. The daily cost in November 2021 alone was £16.8m, representing an increase of 756 per cent from 2019 when the daily cost average was just £1.92m.

National Grid ESO, in an apparent near panic, issued two capacity market notices on July 18 as the UK margin between load and available generation would have been below the threshold set out in the Capacity Market rules. The notices were withdrawn within a short period, no doubt with a huge sigh of relief.

Part of the sticking plaster on July 18 was contracting to import power via the Nemo interconnector from Belgium, with the UK paying energy imbalance prices of £2,059/MWh at 6.30pm with a Nemo peak rate of £9,724/MWh during July 21 being subsequently reported. This contrasts with a UK ‘Day Ahead’ wholesale price that would have been £300-£350 at the time.

Let’s not count either on the UK being able to continue to top up at will in the future from our friends in Europe and elsewhere.

As renewable generation sporadically fluctuates and disappears, we frequently have 50 per cent of our electricity produced by gas. Besides the pan-Europe scramble for gas supplies, Grangemouth fracked gas imports from USA will be at the mercy of shipping in winter weather, as will gas from Qatar should we sign a long-term agreement. Plus we presently have next to no significant storage capacity available in the UK.

France’s ability to supply us cross-channel with comparatively cheap, predominately nuclear-based electricity will be reduced as it pursues its target of reducing the number of ageing nuclear stations by 50 per cent by 2035.

Note, too, that French company EDF - potentially soon to be nationalised by France - intends to close all of its existing UK nuclear stations presently delivering 5.8GW, leaving only Sizewell B at 1.2GW by 2030 “or earlier”, with the UK apparently having no significant influence. This situation had been predicted for years within the profession.

In a dim flicker of hope within the last week it has been reported that EDF is considering seeking limited operating extension permission for Hartlepool and Heysham 1 (due to close in March 2024) dependent upon the results of graphite inspections over the coming months. Who knows the outcome?

Neither can we expect Norway to come to our rescue via the new 1,400MW interlink providing mostly hydro-generated electricity, given that its lake water levels in some areas are at 20-year lows and winter snow melt top-up is expected to be below historical levels.

Germany has well-known gas supply issues and hopes to continue to pursue a nuclear closure policy, although given its grid-transmission limitations from north to south will likely retain two in the south to retain stability. In addition, it is seeking to rent shipboard oil and gas generation from around the world and appears unlikely to be able to supply energy to others.

Given the predictable circumstances allowed to coalesce during this year’s heat wave, we have to question who is running the UK ship. The Met Office gave us plenty of advance warning.

I would define a power system ‘adult’ as an independent, unaligned, unbiased and experienced chartered electrical power systems engineer. It is unarguable that the present, long-predicted UK mess is attributable to there being not enough of such adults in the UK power systems strategy room since privatisation 30 years ago.

The National Grid ESO is due to be wound up shortly in light of Ofgem concerns and replaced with a ‘Future System Operator’. Let’s hope the government recruits suitable ‘adults’ to this FSO; that it precludes our technologically illiterate politicians, and gives the FSO the legal clout to plan, model and establish a security of supply level fit for the UK’s needs.

David B Watson is a chartered electrical engineer who before retirement was manager of projects at Foster Wheeler Energy, based in Glasgow and responsible for project-execution management at the company’s Scottish operation.

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