A major energy conference is going ahead in Riyadh from Sunday despite a Houthi attack on the city’s King Khalid International Airport that killed 12 people and injured 309, according to Saudi Arabia’s General Authority of Civil Aviation.

Saudi Arabia’s Ministry of Energy said on Sunday that the 25th World Petroleum Council Energy Congress has begun in Riyadh. The 17th International Energy Forum (IEF) Ministerial will be held on the sidelines of the conference, called Riyadh Energy Week, which is to run until Thursday.

But Italy, the cohost of the IEF, will join the meeting via videolink. Nigeria, the other cohost, is sending a representative to the event.

The IEF brings together 68 countries that account for more than 90 percent of global oil and gas supplies and demand. Its members include Saudi Arabia, the United States and Russia. The meeting comes as the US-Israel war on Iran has disrupted energy flows and pushed governments to reassess their energy security.

In this visual explainer, Al Jazeera looks at where the world’s energy comes from, how much is produced in the Middle East and which countries have strategic reserves to fall back on. Where does the world’s energy come from?

Energy heats our homes, fuels our cars, keeps the lights on and runs the factories that make what we buy. It comes from fossil fuels such as oil, coal and gas as well as nuclear power and renewables.

Despite rapid growth in renewables, fossil fuels still account for nearly 81 percent of global energy consumption. Oil is the largest source at 31.4 percent, followed by coal at 25.9 percent and natural gas at 23.5 percent. Traditional biomass, nuclear power and other sources make up the rest.

Production is concentrated in a handful of regions, so disruptions in any of them ripple through global markets.

The Middle East is the largest oil-producing region, and North America is the largest natural gas producer. Russia and Central Asia are also major producers of both.

How Middle East energy reaches the world The Middle East’s importance to energy markets is also about geography. Three narrow waterways connect its producers with consumers around the world.

Before the Iran war, about 27 percent of global seaborne oil trade and almost 20 percent of liquefied natural gas trade transited through the Strait of Hormuz on the eastern side of the Arabian Peninsula.

On the peninsula’s western side, the Bab al-Mandeb strait links the Red Sea with the Gulf of Aden, and the Suez Canal connects the Red Sea with the Mediterranean. As the Iran war has spilled over into other areas of the Middle East and Yemen’s civil war has ramped up, traffic has been reduced through both the strait and canal, forcing some energy shipments on longer routes around Africa.

“That’s probably the first time we’ve really seen a major constriction of a chokepoint,” said Richard Matthews, director of consultancy and research at Gibson Shipbrokers, a London-based shipbroking and maritime advisory service.

He told Al Jazeera that what makes the Strait of Hormuz different from other chokepoints is “there is no alternative maritime route. There are some pipelines, but there’s no alternative, which is why it’s been so significant in terms of cargo volume.”Gulf ports are where much of the region’s energy begins its journey to the rest of the world. Which countries rely most on Middle East oil?

Further down the supply chain, people and businesses are feeling the disruption through the rising cost of essentials.

Countries that rely on oil, gas and fertiliser from the Gulf face higher prices, longer waits for shipments and the need to find other suppliers. Even where deals have kept goods moving, the extra costs are being passed down the chain.

Eritrea and Madagascar are the most dependent on Middle Eastern oil, each sourcing about 90 percent of their supply from the region. They are followed by Pakistan (78 percent), Japan (77 percent) and Kenya (77 percent).

Gas has been even harder to replace than oil because most of it travels as liquefied natural gas from Qatar and the United Arab Emirates through the Strait of Hormuz.

Countries that depend on these shipments are paying more for fuel and electricity and competing for a smaller pool of cargoes. Poorer importers with little storage have struggled the most to find alternatives.

The countries that rely most heavily on Middle Eastern gas are mostly in Asia. South Korea sources 31 percent of the gas it uses from the region, followed by India (29 percent), Pakistan (27 percent) and Taiwan (26 percent). Who has the largest emergency oil reserves?

Countries keep emergency oil stocks for when supplies are cut off or reduced, and these have been the world’s main cushion during the war. That cushion is now wearing thin.

Western countries have little left to release, energy industry leaders warned, and the US Strategic Petroleum Reserve is at its lowest level since 1982.

“Estimates suggest less than 6 billion barrels of commercial inventories remain today with the vast majority not practically available,” Amin Nasser, head of Saudi Aramco, told the Energy Intelligence Forum in London on Monday.

The International Energy Agency, which coordinates emergency stocks for its members, released a record 400 million barrels of oil in March. It is now preparing to release another 100 million barrels of crude and diesel to ease soaring diesel prices although some of this may be oil from the March release that has yet to reach the market.

A storm in the Gulf of Mexico and attacks in Saudi Arabia are now threatening supplies again, keeping oil prices above $100 a barrel.

Before this year’s releases, China held by far the largest reserves, an estimated 1.4 billion barrels, more than the rest of the list combined. The US was second with 413 million barrels, followed by Japan with 263 million.