The weaponisation of energy: UK exposure

For an island nation, subsea interconnections with other markets are both a strength and a vulnerability. In the Second World War, overcoming the threat of U-boats and winning the war of the Atlantic proved vital to the UK’s survival. Today, in the event of conflict, in addition to keeping shipping lanes open, the UK would have to defend multiple subsea energy links with Europe.

Yet despite the ease with which subsea infrastructure can be targeted, the UK’s energy security is robust.

Soft energy war

Europe has successfully dealt with the loss of the majority of Russian pipeline gas imports, although at some cost. High prices for natural gas have shrunk European industrial activity and contributed to a widespread cost of living crisis, which, in turn, has fuelled more extremist political sentiment across the continent.

European countries had to invest heavily in new LNG import infrastructure. They burnt coal for longer, extended the life of aging nuclear reactors and accelerated the construction of renewable energy resources, valued now as much for their domestic generation as their environmental attributes.

But the weaponisation of gas has cut both ways. Russian pipeline gas exports in 2023, at 95.4 Bcm, were less than half the 201.7 Bcm pumped in 2021. This is a much bigger hit than Moscow probably anticipated.

The sabotage of the Nord Stream gas pipelines running across the Baltic Sea from Russia to Germany effectively pre-empted Germany’s position on gas trade with Russia, giving it no choice but to invest in LNG import capacity. Responsibility for the explosions remains opaque, but the incident served Ukrainian interests most. Not only had Russia used the supply of gas a means of coercion prior to the pipeline attack, but energy infrastructure outside the immediate theatre of war had become a target.

Since then, a soft war has been playing out in the Baltic Sea, now almost entirely encircled by NATO members after Sweden and Finland joined the organisation in April 2023 and March 2024 respectively. There has been a string of incidents in which subsea infrastructure has been damaged, including fibreoptic cables, electricity lines and gas pipelines.

Subsea infrastructure can be damaged by natural occurrences such as subsea landslides and accidently, typically by fishing activity or ship anchors. It is difficult to differentiate accidents from deliberate sabotage let alone ascribe direct state responsibility. Yet suspicion is high that that at least some of these incidents have been deliberate, leading NATO to announce in January a new initiative to protect critical infrastructure in the region.

Island energy security

The UK and Ireland are dependent on subsea infrastructure to import and export gas, electricity and to receive and transmit data. The vulnerability of subsea infrastructure depends in large part on its depth.

The Baltic Sea is a relatively easy target because it has average depth of just 54 metres. The English Channel is similarly vulnerable with an average depth of 63 meters, leaving the seabed and infrastructure lying on it within easy reach of a carelessly dragged anchor and divers. The Irish Sea, which hosts gas and power interconnections between Wales and Ireland and Scotland and Ireland, is also shallow – mostly 20-100 metres deep.

Moreover, the UK’s import dependence is rising rather than falling, while the Republic of Ireland depends on gas import pipelines running from Scotland, which explains Dublin’s recent decision to invest in its own LNG import terminal.

The UK has also become increasingly dependent on electricity imports as it has phased out coal-fired generation. Although total electricity consumption is lower than a decade ago, the decline in domestic generation has increased the level of imports. Last year, electricity imports rose by 40% to reach a record 33.4 TWh, just over 10% of total demand.

However, this is an economic outcome. Domestically generated power fell by 2.6% to 285 TWh as imports proved cheaper than gas-fired generation. The economics of domestic versus imported power also reflect the tax regime. Renewable energy generation grew and, in combination with higher imports, helped cut domestic generation from fossil fuels by 16%, making the UK electricity system cleaner, but more import dependent.

The increase in power imports is not a physical vulnerability, so long as sufficient gas-fired plant remains operable to replace imports in the event of damage to major infrastructure. The UK has about 35 GW of gas-fired capacity, although it is operating increasingly less often.

Analysis by Kilowatt.io, a UK-based solar data company, in September last year showed that UK gas-fired generation plant was operating at its lowest level since 2017. These plants are kept alive by a combination of revenues from operating at the most profitable times, when other sources of power, such as renewable generation, are low, and capacity payments – in effect payments from the government to have generation capacity available, if it is needed.

The proliferation of power interconnectors also provides security in that all are unlikely to be successfully attacked at the same time. The UK has 9.8 GW of interconnector capacity spread across nine links, three with France and one each with the Netherlands, Belgium, North Ireland, the Republic of Ireland, Norway and Denmark. In November, UK electricity market regulator Ofgem approved three new electricity interconnectors and two offshore hybrid interconnectors, part of the developing North Sea super grid powered by offshore wind, but also connected to other European electricity markets.

Gas supply still critical

The UK’s energy insecurity stems more from its gas system. Electricity generation is vulnerable mainly if there is a physical lack of natural gas. This possibility is highest in winter when UK gas for heating demand soars.

However, the UK has some major advantages relative to its neighbours. While in decline, it still sources around half of its natural gas demand from domestic production, and it has far more gas import capacity that it needs. Much of it is LNG import capacity, rather than pipelines.

The country’s three LNG terminals have import capacity of 48 Bcm/yr, while pipeline connections with Norway, Belgium and the Netherlands provide over 70 Bcm/yr of import capacity. UK gas consumption in 2024 was just over 60 Bcm, about half of which was met by domestic production. As demonstrated in 2022, the UK’s excess import capacity can act a conduit for LNG imports to flow to continental Europe.

Last year, Norway provided 76% of all gas imports and almost all pipeline imports, but, like the UK’s electricity imports, this is a function of economics rather than a problem of physical dependency. Imports via the Belgian and Dutch interconnectors have fallen as northern Europe has become more dependent on LNG and Norwegian gas. Direct Norwegian gas imports are simply the cheapest and most efficient solution, but the UK could import more LNG, if it needed to.

The UK’s main vulnerability is its dependence on the 25.5 Bcm/yr Langeled pipeline from Norway, but while outages on this line cause immediate price reactions in the UK gas market, there is sufficient excess capacity in the country’s LNG terminal and other import pipelines to compensate even if Langeled were taken out of operation completely.

Storage capacity still low

A second vulnerability is the low level of gas storage. In January, the UK’s largest gas supplier Centrica announced that the country had less than a week of stored gas. Gas Infrastructure Europe data showed that of 20 European countries listed, the UK had the least gas in storage.

The UK has storage capacity of about 3.2 Bcm, compared with about 22 Bcm in Germany and 16 Bcm in the Netherlands. It copes because of its domestic production and the diversity and size of its import options, but there is little doubt that increased storage capacity would enhance the country’s energy security. LNG might be flexible, but it takes time for unscheduled LNG Carriers (LNGCs) to arrive.

In the event of conflict, it is the sea that is the UK’s greatest lifeline and vulnerability. Any conflict on the European continent would probably make the physical operability of European interconnectors moot, as gas and power availability and demand would be affected further up the supply chain.

The UK imports more than 40% of the food it consumes and the only way of securing continued deliveries of both food and LNG would be by ship. Today, the Royal Navy is about 25% smaller than in 2000, while the merchant navy in 2023 numbered just over 1,000 ships, having accounted for a third of registered global tonnage in 1939. As LNGCs are not known for sailing into war zones, keeping the seas open to shipping still presents the UK’s greatest security challenge.