At seven minutes to five on the afternoon of 9 August 2019, a lightening strike caused the loss of 150MW of distributed power (i.e., a large number of small wind, diesel and solar generators) from the National Grid. This sudden loss triggered the safety system on the giant Hornsea wind farm in the North Sea, taking another 799MW of power from the system. Fortunately, regulations at the time required that the Grid operator keep 1GW of back up capacity for precisely this kind of emergency. And so standby turbines at the Little Barford gas power station were started. However, the system failed, taking 244MW of Little Barford’s power offline too. This loss of power tripped a further 350MW of distributed generation bringing the total loss of power to 1,481MW. Within the next minute, 900MW of National Grid’s 1GW of backup capacity was brought online, stabilising the frequency at 49.2Hz. Seconds later, however, the gas turbine at Little Barford failed; bringing the loss of power to 1,691MW. At this point, National Grid had consumed all of its 1GW backup capacity and had no resource to cope with further power losses or frequency fluctuations. Then, half a minute later (16:53:50) the frequency fell to 48.8Hz; triggering the Low Frequency Demand Disconnection scheme and automatically disconnecting 1.1 million business and household consumers. In response, and for yet to be discovered reasons, (16:53:58) a third turbine at Little Barford went offline bringing the total loss of power to 1,878MW – nearly double Ofgem’s stipulated backup capacity.
Network Rail was among the large industrial users in the Low Frequency Demand Disconnection scheme, so that at the peak of the Friday evening rush hour, a large part of the UK’s rail network was brought to a halt. So too was a large part of the domestic supply to homes across the eastern half of the country’ together with several hospitals. But it was hardly – as the Grid operator tried to claim – out of the blue. As Jillian Ambrose at the Guardian pointed out in response to the official report into the incident:
“In the last 12 weeks the grid’s frequency has fallen dangerously low, below 49.6Hz, on three separate occasions. Prior to these near-misses the grid’s frequency had not fallen to this extent for at least the last four years.
“National Grid had managed to avoid a wide-spread blackout until now by triggering a ‘low frequency event’ which sends out a call to contracted energy companies for immediate back up, with only 10 seconds’ notice.”
One reason why all concerned were keen to present the failure as an unforeseeable event is that it was well known that adding a significant amount of intermittent wind and solar generation would create precisely these kind of frequency failures. Unlike coal, gas and nuclear plants, which use steam to spin massive turbines, non-renewable renewable energy-harvesting technologies (NRREHTs) have no inertia to provide a buffer – and vital seconds – while the Grid operator starts up its backup facilities. So that – as happened on 9 August 2019 – any backup failure automatically triggers power cuts across the system.
Although various forms of energy storage might theoretically provide an alternative buffer to the lost inertia from the giant spinning turbines, they have yet to be built at anything like the scale needed. Moreover, even the cheapest – pumped hydro – costs several billion pounds (and the flooding of Scottish and Welsh valleys) making it politically difficult to develop.
One even cheaper – and less politically contentious – option though, has been developed in recent years. If the UK cannot provide sufficient backup for its increasingly intermittent system, then we can import backup power from our European neighbours. Indeed, out of the glare of the media, one of the earliest post-Brexit agreements between the EU and the UK allowed the UK to maintain its membership of the European energy system.
The UK’s interconnectors currently have a capacity of 6GW – 3GW from France, 1GW each from Belgium and the Netherlands, and 500MW each from Northern Ireland and the Republic of Ireland. And just as well, because the UK system is regularly short of supply. Indeed, just last month (August 2021) a combination of high pressure and unbroken low cloud left wind turbines and solar panels idle. Wind accounted for 18 percent of our monthly consumption, solar just 6 percent. Gas provided 36 percent and nuclear a further 15 percent. Another 15 percent was imported to make up the shortfall.
With most of Europe on a course to swap out fossil fuel generation in favour of NRREHTs, this sharing of the backup capacity appears to make some sense. If the wind isn’t blowing in Britain, we need not worry because the sun will be shining in Spain. And in any case, there are still – for the time being – plenty of Belgian and French nuclear power stations to call on. And even Germany – which insanely closed down its nuclear power plants – there are still plenty of coal plants to provide power.
This though, may prove to be wishful thinking according to Martien Visser, a Lecturer in Energy Transition and Grid Integration at Hanzehogeschool Groningen and Manager of Corporate Strategy at Gasunie. Writing in Innovations Origins, Visser argues that a pan-European Grid will result in Pan European outages sooner or later. Indeed, a few near misses have already occurred:
“Friday afternoon, January 8, 2021. A substation in the power grid in the Balkans breaks down. Almost immediately, the problem scales up to European dimensions. A blackout is prevented thanks to the quick intervention of European grid operators. Industries in France and Italy are switched off. It could have all ended very differently. An investigation produced no less than 20 recommendations for improving the situation. But on Saturday, July 24, it was an absolute disaster. In Spain, more than 600,000 households were left without power because an airplane flew into a high-voltage cable in France. According to experts, it was a stroke of luck that it happened over the weekend. The lesson: Failures in one country can have major consequences in others.”
The problem is that as countries come to rely on backup capacity from neighbouring states, they are less inclined to make the eye-wateringly high investments needed to provide the national backup capacity required to operate increasingly intermittent systems. But this growing interdependency fails to account for national – political – decisions which have consequences across the continent:
“The collective energy interdependency of European countries is increasing even more. Which makes it fairly strange that energy policy is largely a national affair. Needless to say, analyses of the reliability of the energy system are carried out regularly in Brussels. These conclude that the system is in order. But what scenarios are they basing this on? And which political decisions? Was the recent Dutch decision to limit coal use to 25% factored in? What about Belgium, which is threatening to close its nuclear power plants without any adequate replacements? And the new German government, which is likely to accelerate the Kohleausstieg, i.e. the fossil-fuel phase-out. And how about the discussion in the Netherlands concerning the permanent closure of the Groningen system as an emergency reserve for the northwest European gas market?
“Economic theory teaches us that in a free market, supply security is automatically guaranteed. Well, almost always that is, see Texas, among others. The question is whether this economic theory still holds true given the many politically driven decisions. Of course, asking that question effectively answers it. Meanwhile, our society is becoming increasingly dependent on an undisrupted energy supply. While scarcity not only leads to risks to supply security, but also to a sharp increase in energy prices. This is something that we are also seeing right now… continuing on the current path will almost certainly lead to accidents. The question then is not if there will be a European blackout (electricity and/or gas) over the coming years, but when…”
The political imperative – driven almost entirely by concerns about climate change – is to switch over to renewable energy as quickly as possible. Indeed, not only are they attempting to replace fossil fuel electricity generation with NRREHTs, but they plan to expand generation capacity five-fold in order to power transport, domestic heating and cooking together with a large part of industry and agriculture. But without a practical solution to the storage-backup problem, we move ever closer to both national and pan-European blackouts. And given the complexity of an increasingly continental Grid, this could mean households and businesses being cut off for weeks at a time.
As you made it to the end…
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