Saudi Arabia is preparing to reveal the size of its oil reserves as the world’s biggest oil exporter prepares to sell the shares in Saudi Aramco.

“This is going to be the most transparent national oil company listing of all time,” the kingdom’s energy minister Khalid al-Falih, told the London-based Financial Times.

The size of Saudi Arabia’s reserves is one of the most closely guarded secrets in the oil industry, The kingdom has not revealed the exact extent of its proven oil reserves since it completed the nationalisation of the formerly US-controlled Saudi Aramco in the 1980s. Since then reported reserves have remained around the 260 billion barrels mark. International energy executives and investors have not been able to verify the government’s figures.

Al-Falih said independently audited numbers would soon be disclosed.

“Everything that Saudi Aramco has, that will be shared, that will be verified by independent third parties,” he told the newspaper, adding this would include financial statements, “reserves?…?costs [and] profitability indicators”.

Investors have been speculating about whether the kingdom’s crude reserves details will be shared in an open and transparent manner since the country’s all powerful Deputy Crown Prince, Mohammad Bin Salman al-Saud, in January announced plans to list Aramco.

The kingdom’s reserves are not expected to be part of the share sale, which is expected to take place in 2018 on Saudi Stock Exchange and a yet undecided international bourse. The government will have sovereign right over the management of reserves, but they do factor into the company’s valuation, which Riyadh believes could be as high as $2 trillion.

If the government data proved accurate, this would mean that the kingdom has managed to replace each barrel it has produced with oil from new discoveries or higher estimates of the amount of oil it can recover from existing fields. The information is likely to affect oil markets as it can potentially indicate how long Saudi Arabia can keep on pumping crude.

The country’s sovereign bond prospectus last month said reserves could last for approximately 70 years but stipulated the estimate had not been reviewed by a third party.

Al-Falih, who is also Saudi Aramco’s chairman, said Aramco had the potential to become an industrial conglomerate rivalling US’ General Electric.

“You look at a company like GE that is [in] everything from aerospace to healthcare to lighting to oil and gas. Saudi Aramco can be multiples of GE if we put our mind to it,” he said.

Saudi Arabia is also close to finalising a tender for a sharp increase in the amount of renewable power it uses domestically, according to the minister. The country has mainly relied on natural gas and oil for its energy but aims to install nearly 10GW of solar, wind and other types of clean power by 2023, which Al-Falih said would amount to about 10 per cent of peak demand.

The kingdom hopes to that as much as 30 per cent of the electricity could come from a mix of renewables and nuclear power, though, there are no “imminent” plans to build a nuclear plant.

“We’re in the process of putting one large wind turbine in the kingdom as a demonstration,” he said, adding another tender for a “major wind energy project” would be launched after the first turbine had been tested.