Both Hezbollah and the Houthi militia in Yemen have proven adept at low-cost drone attacks capable of damaging fuel depots and power plants – energy infrastructure that is fragile and in some cases located at the same site.

Meanwhile in Ukraine, both Moscow and Kyiv have realised that air power can be supplemented with cheap long-range drones to devastate power plants and refineries.

The 2006 war between Israel and Hezbollah provides a glimpse of how serious the impact of such attacks could be.

“In 2006 Israel bombed the Jiyeh power plant storage tanks in southern Lebanon and that caused an environmental disaster,” says Noam Raydan, an energy expert at the Washington Institute for Near East Policy.

“Now Lebanon is suffering from an energy crisis and the government can barely afford purchasing oil products to keep the Zahrani and Deir Ammar power plants running, and not all the time. If in the future Hezbollah targeted Israel’s energy or maritime infrastructure, in any way, Israel will likely retaliate by hitting Lebanon’s fragile infrastructure. The situation is extremely worrying.”

One area of fragility for both countries in wartime is hospitals.

Israel appears to be preparing for this scenario, with patients at hospitals in the north, closer to the Lebanon border, being moved to the centre of the country, the Israeli Channel 12 news station reported on Tuesday.

The situation is much more dire for hospitals in Lebanon, where a continuing economic crisis has left the government unable to pay for sufficient fuel imports needed for power plants as well as for diesel generators.

Many hospitals in Lebanon are now almost entirely dependent on generators because of extended power cuts by the state electricity company. In March, hospitals in the south reported shortages of fuel as well as medical supplies as a result of the economic crisis and the near daily exchanges of fire between Hezbollah and Israel since October.

Israeli strikes on Lebanon in the 2006 war and the economic crisis that hit in 2019 show how wide-ranging the disruption created by fuel shortages can be.

In one area of Lebanon in 2006, 42 out of 70 villages had no water because there was no electricity, or fuel, for water pumps. Aid agencies had to deliver water to Beirut. By one count, Israel hit a total of 17 fuel storage sites in Lebanon.

In 2021, water authorities stopped pumping and began rationing in northern Lebanon because of fuel and electricity shortages.

A new war could make things far worse, with Israel possibly hitting up to 3,000 targets in a single day, and Hezbollah launching 5,000 rockets, missiles and drones – although estimates vary significantly.

“In such a scenario, generators would be our backup plan,” says Marc Ayoub, a Lebanese energy expert.

“We need to check the quantities of imported diesel; last time I checked, we had no reserves for more than one month. Knowing how much diesel we have is crucial. In any case, diesel generators cannot operate all day because they are backup generators, so there will be rationing.”

Israel is less dependent on oil for electricity production than Lebanon, although it is reliant on power-hungry desalination plants to meet its water needs.

About 37 per cent of its energy production comes from oil, according to the International Energy Agency, while most comes from natural gas.

Hezbollah has said it would target storage and infrastructure for the latter in a conflict.

Emergency plans

Energy officials In both countries are cagey about their preparedness for war – one Lebanese government official told The National that the matter was too sensitive to discuss.

“The Lebanese authorities proposed an emergency plan six months ago, but it's not clear if it has been updated. There might be a risk of no more shipments of Iraqi fuel because of the war, which could leave us without fuel. This is a major concern,” Mr Ayoub says.

However the increased use solar power, which now accounts for about a third of Lebanon's 3 gigawatt production capacity, could help, he says.

In Israel, Shaul Goldstein, head of the government-owned Independent System Operator that manages electricity infrastructure, apologised after saying last month that a full-scale war with Hezbollah would make “living here impossible”.

Other energy officials said the risk was less severe. The Israel Electric Corporation, the country's largest power supplier, has said backup generators and additional electricity substations have already been prepared in anticipation of war in the north.

But substations – critical nodes that manage distribution in a power grid – are another point of vulnerability, a fact IEC admitted.

In Ukraine, Russia has damaged or destroyed substations with Iranian Shahed drones, which Iran-backed Hezbollah uses under the name Ayoub. These drones are designed to fly into targets and explode.

The drones are a problem for Ukraine, even though interception rates during attacks are often more than 80 or 90 per cent.

Sustained bombardment with Shaheds – about 4,600, according to Kyiv – contributed to the loss of about nine gigawatts from Ukraine's production capacity.

Hezbollah is said to operate about 2,000 drones of varying designs, mainly “advanced” models, according to Israel's Alma Research Centre, a think tank.

“Assuming the other side has 2,000 UAVs [drones] you should assume how many will be intercepted, how many will miss their targets, and how many will be destroyed before launch. The other side’s UAVs probably won’t have a strategic impact in a full-scale conflict,” says an Israeli security expert who has worked extensively with drones, speaking off record.

The expert said he believed Israel could absorb the expected damage from a war that would nonetheless “have its cost”.

Although Israel's air defences have coped well with Hezbollah's drones and rockets so far, the scale of these attacks is expected to increase significantly if war breaks out.

Estimates of Hezbollah's capacity for rocket and missile launches vary between 1,000 and 3,000 per day, out of an arsenal thought to be as numerous as 150,000 rockets and missiles.

Most of the group’s rockets are unguided and short range but it has invested considerable time smuggling components and new weapons through Syria to enable precision, guided, long-range strikes.

The Israeli Defence Ministry’s National Emergency Management Authority recently assessed that Hezbollah could launch 5,000 attacks a day across the border, including drones.