In August, the simultaneous failure of two power stations in the UK led to power outages that affected around one million people across the country. While the stations were back online within 15 minutes, the consequences of the blackout were more dramatic, with some local power suppliers unable to meet demand for close to an hour, and disruptions to signalling systems and power supply equipment leaving train passengers stranded for a further six hours.

These events highlighted two concerns for the UK’s power industry, one technological, and one political. The fallout of the blackouts demonstrated the National Grid’s relative lack of flexible power generation systems, such as advanced battery technologies, which can be used to plug holes in power supply in times of shortages, but were absent during the recent outages. More broadly, the influence of the EU in UK power generation has been called into question, with the body cancelling an energy auction last year that would have seen the UK award contracts for some of these backup power systems.

The National Grid’s emergency systems were able to prevent the blackout from spreading across the country, but the episode has highlighted the importance of coherent policy and the adoption of new technologies to ensure power reaches vital services and people in need.

The power cut itself

The power cut itself was described as an “extremely rare and unexpected event” by the Office of Gas and Electricity Markets (Ofgem) in its report into the incident with a number of unrelated power outages combining to affect customers over such a large scale. The report highlights “heavy rain and lightning storms” occurring just prior to the blackout, which triggered a process known as vector shift protection, which automatically reduces output by 150MW to ease the strain on the network.

This automated safety response was to be expected, but subsequent unrelated simultaneous technical faults at the Hornsea offshore wind farm and Little Barford steam facility cut a further 1GW of power from the grid, before a further fault at a Little Barford gas turbine reduced the total power output by 1.7GW, as the supply crisis spiralled.

The outages also triggered a collapse in the grid’s electrical frequency, a measure of the rate at which the grid’s electrical current changes direction. The National Grid can safely operate at a frequency of between 50.5Hz and 49.5Hz, but the frequency plunged as low as 48.8Hz during the blackout; this caused an automated safety system known as the Low Frequency Demand Disconnection scheme (LFDD) to activate and take a further 350MW of power out of the grid, lessening the burden on the stretched network, and allowing the frequency to recover to a safe level.

While this approach prevented additional stress from being placed on the network, helping to avoid larger-scale blackouts, the loss of power did have a significant impact in a small number of areas. Ofgem reported that 60 trains shut down without warning as power to National Rail services was cut, alongside “critical failures” at Ipswich Hospital and Newcastle Airport, with the latter’s electricity cut as part of the LFDD triggering. The incident, and the National Grid’s response, has therefore raised questions about alternative responses to significant outages, and how the LFDD can more effectively prioritise services to be cut in case of emergencies.

EU loggerheads mean no auctions, and no backup

Following the blackout, Ofgem recommended conducting a review of LFDD operations, to ensure “critical infrastructure [and] services” are not abandoned to protect the network as a whole, but there are larger structural issues with the UK’s power generation that could be addressed.

Last year, the EU cancelled a power auction in the UK where companies were offered contracts to provide short-term power to avoid blackouts as the country shifts from an energy mix dominated by fossil fuels to one that makes greater use of renewables. The system was approved in 2014 by the European Commission, and saw contracts worth £5.6bn handed out to power generators, mostly declining coal, gas and nuclear plants, to shift to renewable energy without disrupting power supply

However, British energy technology firm Tempus Energy appealed against the auctions, claiming they are little more than subsidies for fossil fuel power sources, and won’t improve the environmental performance or efficiency of the UK’s power grid in the long term. The EU’s General Court then called for an investigation into the market, to ensure it does not contravene the body’s strict laws on state aid, which prevent national governments from propping up struggling private companies, and called on the National Grid to postpone two rounds of upcoming auctions indefinitely.

In the short term, this caused share prices in the companies awarded contracts to plummet, but has now affected a much larger number of people across the country, with the UK deprived of the energy backup system it had come to rely on.

The episode highlights the legal grey areas involved in international power generation; the UK is primarily interested in ensuring its citizens have constant access to electricity, while the EU is invested in ensuring no one member state distorts the energy economy of the continent without good reason. While the two stances do not put forward an inherent conflict of interest, they are far apart enough that a thorough re-negotiation of the UK’s relationship with the EU could be necessary to ensure a consistent supply of backup power.

However, with the confused state of Brexit, there is little chance of such a negotiation taking place, or being productive. Even should the UK leave the EU without a deal and trade with Europe using World Trade Organisation rules, as some expect, the international body has its own set of state aid laws, which could mean the UK is merely pushed to loggerheads with a different organising group, rather than able to secure the power supply it feels it needs.

Flexible power generation: a panacea

Flexible power generation has been touted as a possible answer to the world’s energy supply issues. While the concept is theoretically broad, it generally refers to forms of power generation that can quickly adapt to changes in energy supply, to ensure that blackouts are less frequent and excess power is not produced and wasted. Renewable power is one key part of this flexible approach, and so too is advanced battery technology, with the two innovations often paired for the best results: renewable power systems produce as much power as possible given environmental conditions, and any power produced that exceeds demand is fed into a connected battery storage system.

The most obvious example is Tesla’s “big battery”, the colloquial name for the Hornsdale Power Reserve in Australia. The complex stores power from the nearby Hornsdale Wind Farm, around 70% of which is then sold to the local South Australian government, while the remaining 30% is sold on the open market; Renew Economy estimates that the project may have made up to A$1m over the first two days of operation, setting the battery on course to recoup its initial costs within 100 days.

The UK has already begun to adopt flexible power principles, with Ofgem reporting that there is 472MW of battery storage in use in the UK grid, although all of this capacity was used to regulate the grid’s frequency following the blackout, highlighting the need for greater investment in this technology in the future. If the UK can embrace flexible power generation, and effectively embed renewable power and advanced battery technologies into its grid infrastructure, the country could be at a significantly lower risk of blackouts in the future, regardless of continental and international political developments.