Many operate in the stable "midstream" part of the energy business, merely collecting a toll for transporting and storing oil and gas.

WSJ: Upside: Oil Partnerships Keep Rolling

To keep prices elevated, someone would have to be buying this amount of oil every day, and keep on buying and storing this amount indefinitely.

FORBES: Are Speculators Responsible for Today's Higher Oil Prices?

"Given the pressing need to reduce our dependence on fossil fuels, especially oil, and to cut CO2 emissions, the future for hydrogen as an alternative means of storing and utilising energy cost-effectively has never been brighter, " said Jim Heathcote, chief executive of ITM.

BBC: Hydrogen refuel station unveiled