- What could be targeted? -

Previous airstrikes from the United States and Israel during the more than five-week war have hit energy infrastructure such as gas production facilities or oil depots, as well as transport routes.

But taking any of Iran's roughly 90 power plants offline would represent a major escalation with immediate consequences for civilians and the local economy.

Iran's abundant gas reserves are used to generate around 79 percent of the country's electricity, according to the Paris-based International Energy Agency.

Its power stations are clustered around the biggest urban and industrial areas in the north, particularly around the capital Tehran, as well as the Gulf coast which is close to the main gas reserves.

The biggest plant is Damavand, which supplies the capital, followed by Shahid Salimi Neka in northern Mazandaran province, and the Shahid Rajaee plant in northern Qazvin province, according to Iranian power infrastructure group MAPNA.

Brenda Shaffer, an energy expert at the US Naval Postgraduate School, told AFP: "It is important to point out that Iran was undergoing a very severe energy crisis prior to the start of the current war.

"Iran has chronic shortages in electricity, natural gas and refined oil products."

- Would targeting power help the US militarily? -

No, according to the Washington-based Atlantic Council think-tank.

"The Iranian military has only limited ties with the national electricity system," analysts Joseph Webster and Ginger Matchett wrote on Monday.

"Instead, like most militaries, the Iranian military primarily uses middle distillates, especially diesel and jet fuel."

Strikes would "harm Iran's critical infrastructure and civilian population, while doing little to harm the Islamic Republic's military capabilities," they added.

UN rights chief Volker Turk on Tuesday decried the "incendiary rhetoric" in the Middle East war, warning that deliberate attacks on civilians and civilian infrastructure was "a war crime".

Nishant Kumar, a Middle East energy expert at the Rystad Energy consultancy, told AFP an attack on a power station would destabilise the Iranian grid and lead to rolling localised blackouts.

"Sectors such as steel, cement, petrochemicals, and automotive manufacturing cannot operate under unstable power conditions or rolling blackouts," he added.

Back-up power systems such as diesel generators would be critical for essential services such as hospitals, but they must be regularly resupplied.

"Banking and telecommunications are among the most vulnerable sectors. ATMs and bank branches generally have limited backup power, while mobile network towers rely on batteries that typically last only two-four hours," he added.

Iran's power network is interconnected with those of its neighbours such as Turkey or Armenia, but their capacity to provide more energy is limited.

- How would Iran respond? -

Despite its more limited military capabilities, Iran has sought to mirror US and Israeli attacks so far, seeking to match targets in Israel or the Gulf region with those hit inside the Islamic republic.

For example, when Israel attacked its South Pars gasfield in mid-March, Tehran responded by damaging a key liquefied natural gas production facility across the Gulf in Qatar.

Iran's Revolutionary Guards warned Tuesday that its response could "go beyond the region" and would include infrastructure "to deprive the United States and its allies of oil and gas in the region for years".

They also noted that Iran had "exercised great restraint for the sake of good neighbourliness", in a veiled threat to Gulf countries whose energy production facilities, pipelines and ports are crucial to the world economy.

Iran's military has in the past also threatened the crucial water desalination infrastructure of its neighbours.

Desalination plants provide 42 percent of drinking water in the United Arab Emirates, 70 percent in Saudi Arabia, 86 percent in Oman and 90 percent in Kuwait, according to a 2022 report from the French Institute of International Relations think tank.

In the event of escalation by the US and Israel, Iranian military officials have also indicated they would fully activate their Houthi allies in Yemen, who joined the war in a limited capacity in late March.

The Houthis could begin disrupting shipping through the Red Sea, as they did during Israel's war on Gaza.

They are also "nearer and better placed" than Iran to hit Saudi infrastructure and Western bases in the Gulf, Farea Al?Muslimi, a research fellow at the London-based Chatham House think-tank told AFP recently.