Spare capacity in the oil market will shrink significantly next year as travel rebounds and due to a lack of investment among producers, according to Saudi Aramco.

Surplus capacity is the equivalent of 3 million to 4 million barrels a day and will drop as demand for jet fuel increases, Chief Executive Officer Amin Nasser said.

“The buffer might diminish, especially next year,” he said Tuesday via video during the Nikkei Global Management Forum.

Airline fuel is one of the last oil products for which demand is still down heavily since the onset of the coronavirus pandemic. Daily use of jet fuel and kerosene stands at about 5.5 million barrels, compared with almost 8 million in 2019, according to the International Energy Agency.

Overall oil consumption will climb above 100 million barrels a day in 2022, according to Nasser. That would take it close to record levels.

Diminishing spare capacity is made worse because too few oil companies are trying to raise their output capacity, he said.

“Renewable energy can’t yet meet the world’s energy needs,” he said. “Oil and gas demand will remain healthy” for decades.

Still, Aramco is investing heavily in blue hydrogen. The company is talking to potential buyers in Japan and South Korea about supply contracts, Nasser said.

“These are huge investments and we need off-take agreements for them” to work, he said.

Blue hydrogen’s made by converting natural gas and capturing the carbon emissions. Hydrogen is seen as crucial for the transition to cleaner energy since it produces only water vapor when burned.