Natural gas could turn out to be the real pressure point as Europe’s reliance on Russian energy is dialled down.

There are other exposures, direct imports of diesel for example, but gas is critical not just because it is important, fuelling almost half of Irish electricity generation, but because the wherewithal to import is physically constrained.

Gas comes in liquefied natural gas (LNG) carriers or in pipelines.

LNG carriers are specialised vessels, akin to oil tankers, which ferry natural gas around the world in liquid form.

If US president Joe Biden succeeds in diverting some US supplies to the EU as he has promised, none will be coming to Ireland

The gas is liquid at very low temperatures, reduced in volume by a factor of 600.

There are about 700 LNG carriers in operation and the seaborne trade is growing. But it needs onshore facilities and Ireland has none anywhere on the island.

If US president Joe Biden succeeds in diverting some US supplies to the EU as he has promised, none will be coming to Ireland since there is no place for Ireland’s share to land.

There are no transatlantic pipelines

The only route for imports is by pipeline and the only pipelines come from Britain, carrying gas most of which originates in the UK’s zone of the North Sea and in the Norwegian sector.

There are no transatlantic pipelines.

Moreover, the UK is no longer a member of the EU and it is unclear how gas allocated to Ireland under a future EU gas-sharing deal would be transmitted through the UK system to which EU directives and regulations no longer apply. Brexit has a tendency to keep creating fresh headaches in unexpected areas.

If gas gets to be allocated outside the market, the electricity generation sector will get priority: who wants to risk blackouts? The residential sector and space-heating demand are next in terms of volume but attention will focus first, should rationing become necessary, on industrial demand.

One of the sectors at risk is food processing, in particular dairy companies

Firms could be ordered to curtail gas requirements and will have incentives anyway to substitute away from gas which looks likely to stay expensive for the foreseeable future. One of the sectors at risk is food processing, in particular dairy companies.

Out of the total industrial demand in the last ‘normal’ year of 2019, about 30% went to the food sector whose reliance on gas has risen sharply.

At one time, the milk processors used mainly heavy fuel oil but, measured in energy equivalents, gas usage is now around four times the oil figure.

As the gas pipeline network was extended around the country, including in Northern Ireland, most of the plants opted for gas which was more favourably priced and has lower carbon emissions.

Indeed the extensions to the pipeline network were, in several cases, impossible to justify on the basis of space-heating demand in the homes and offices of small provincial towns.

Oil may prove cheaper into the medium term and there are no problems about physical importation facilities

But they got the nod on the basis that there was a decent industrial load available nearby and there was little attention paid to security of supply.

That situation has changed in recent months.

Gas is expensive and users could face curtailment. Oil may prove cheaper into the medium term and there are no problems about physical importation facilities.

There are other industrial sectors which consume gas, or electricity substantially generated from gas, which will come into the reckoning if rationing has to be contemplated

Some processors have retained their capacity to use oil and, with a little refurbishment work, may be able to switch back.

Others no longer have an option unless they are willing to spend serious money and will be reluctant to do so if they feel the superiority of the oil option will prove temporary.

There are other industrial sectors which consume gas, or electricity substantially generated from gas, which will come into the reckoning if rationing has to be contemplated.

One of these is identified in the energy consumption statistics prepared by the Sustainable Energy Authority of Ireland (SEAI) as “metals” and, while individual companies are not identified, Aughinish Alumina is likely the biggest component in this group.

It consumes half as much gas as the entire food sector, and needs a fair electricity load too.

Data centres

Another big energy user is the data centre industry, which adds to the gas requirement through its enormous appetite for electricity.

If the food industry with its strong backward linkages into the Irish economy comes under pressure over its energy usage, Government will have to do the sums about the domestic value-added arising from the various industrial sectors.

Data centres use imported equipment and employ very few people.

They are essentially exporters of electricity and it is fair to ask why the IDA was so enthusiastic about attracting them to Ireland in such numbers. The Aughinish plant makes alumina for immediate export out of imported bauxite, using serious quantities of gas and electricity to do so, and without significant backward linkages aside from the wage bill.

The dairy processors, in contrast, are the route to market for an important national industry, the most remunerative line of primary production for Irish farmers.