According to the compilation of the McKinsey Global Institute's "Aftereffects: Energy Security Beyond the Strait of Hormuz Crisis" report, the disruption in the Strait of Hormuz was the largest energy supply disruption of the modern period.
In the period before the US/Israel-Iran War, approximately 20 percent of global oil supply and approximately 20 percent of global liquefied natural gas (LNG) trade passed through the Strait of Hormuz.
During the peak period of the outage, 14 percent of global oil and gas supplies were disrupted. This rate was twice as high as the impact of oil shocks in the 1970s and six times higher than the peak impact of the Russia-Ukraine war in 2022. Oil constituted 91 percent of the affected energy supply.
On the natural gas side, the global impact was more limited. In the process, only 3 percent of gas supply was directly affected. Although one-fifth of global LNG trade passes through the Strait of Hormuz, LNG accounts for less than 15 percent of global gas supply.
Alternative routes and stocks came into play
While approximately 21 million barrels of oil per day passed through the Strait of Hormuz in the last quarter of 2025, approximately 3.3 million barrels of oil per day continued during the crisis period.
According to the report, before the crisis, China and other countries were increasing their oil stocks. With the effect of the suspension of these purchases, the oil supply-demand gap that needed to be replaced in the global system was calculated as approximately 15.5 million barrels per day.
Approximately 35 percent of this amount was covered by rerouting through alternative pipelines and increased production outside Hormuz. With the more intensive use of Saudi Arabia's East-West Crude Oil Pipeline and the United Arab Emirates' pipeline to Fujaira, an additional daily oil flow of approximately 4.7 million barrels was released to the market, bypassing Hormuz.
Additional production from producers other than Hormuz, especially Brazil, Kazakhstan, the USA and Venezuela, contributed approximately 500 thousand barrels per day.
Using oil stocks to meet needs covered 20 percent of the oil deficit. In this process, approximately 3.5 million barrels of oil per day were used from global stocks. Approximately 2.5 million barrels of this came from the coordinated stock use of International Energy Agency members, and approximately 1 million barrels came from China.
Approximately 45 percent of the remaining amount was offset by a decrease in oil consumption of 6.8 million barrels per day.
Refinery losses and fragility increase supply risk
According to the report, although these mechanisms increase the resilience of the energy system to shock, the limits of these tools are becoming increasingly evident.
As of the end of August, approximately 500 million barrels were used from global stocks. It is calculated that this corresponds to the five-day oil need of the global economy.
During this period, the pressure on the refinery system is also increasing. At refineries in the Gulf, more than a quarter of production fell due to direct damage as well as disruptions across the Bosphorus. Approximately 2 million barrels per day of refinery capacity in Russia was disabled in mid-July. Even though facilities in other regions operate at close to full capacity, they cannot fully compensate for this loss and lead to an increase in global prices.
The temporary closure of Saudi Arabia's East-West Crude Oil Pipeline, which was used as one of the alternative routes to Hormuz, in September as a result of the attacks, is among the factors that show the fragility of alternative routes to regional developments.
New pipelines could deliver 13 million barrels per day of alternative capacity in 2030
According to the report, if currently ongoing or discussed measures to increase energy security are implemented by 2030, 35 to 70 percent of pre-crisis oil flows could be compensated in the event of a possible new Hormuz shock. This rate corresponds to a daily oil flow of approximately 7 million to 15.5 million barrels.
McKinsey stated that the calculation in question is not a prediction, but shows the potential that may arise if the projects and measures on the agenda are realized.
While the pipelines bypassing Hormuz had a spare capacity of approximately 4.5 million barrels per day before the crisis, this capacity was expected to reach approximately 6.5 million barrels in 2030 with the investments planned before the crisis.
It is estimated that if the additional pipeline projects that came to the agenda after the crisis are implemented, the total alternative diversion potential to Hormuz could increase up to 13 million barrels per day.
In the report, a pipeline option discussed between Iraq and Turkey, increasing the capacity of Saudi Arabia's East-West line, and a third line that could connect the inland oil fields in the UAE to Fujairah Port were listed among the projects on the agenda.
It was pointed out that energy security is based on effectively managing dependencies rather than completely eliminating them, and that tools such as alternative supply sources, new trade routes, strategic stocks, electrification, clean energy and demand management should be evaluated together against future shocks.
