The head of the oil behemoth Saudi Aramco said on Tuesday that a lack of recent investments in the oil sector could lead to a shortage of supplies.
"Not much investments have been going into the energy sector ... US$1 trillion has been either deferred or cancelled" amid the price slump of recent years, the state juggernaut's chief executive Amin Nasser said at the Future Investment Initiative conference in the capital Riyadh.
Of that, $300 billion was due for investment in oil exploration and $700bn for project development, he said.
"This will have an impact on the future of energy if nothing happens," Mr Nasser said, pointing to additional needs due to "natural depreciation of fields and normal rise in demand".
Mr Nasser also said renewable energy will not threaten the position of oil and natural gas as the main global energy sources.
"We are witnessing a transformation ... But it will be decades before renewable energy takes a major share in the energy mix," he said.
Global oil prices more than halved in 2014 because of oversupply and weak global economic growth.
The prices have made a partial recovery after producers from Opec and non-Opec countries agreed last year to cut production by 1.8 million barrels per day.
The initial six-month deal was further extended by nine months until the end of March.
Saudi Arabia, the world's top oil exporter, made the largest cut of around 500,000 bpd. It has said it will increase the reduction to 560,000 bpd in November.
The kingdom has lost hundreds of billions of dollars in oil revenues since mid-2014 and as a result posted huge budget deficits.
It has launched a package of economic reforms that include a plan to sell up to 5 per cent of state-owned Aramco.
Mr Nasser said the IPO, expected to raise $100bn if Aramco is valued at $2tn, will take place in the second half of 2018.