What are the issues that will shape the global energy market in 2018? What will be the energy mix, trade patterns and price trends? Every country is different and local factors, including politics, are important. But at the global level there are four key questions, and each of which answers is highly uncertain.

The first question is whether Saudi Arabia is stable. The kingdom’s oil exports now mostly go to Asia but the volumes involved mean that any volatility will destabilise a market where speculation is rife. Crown Prince Mohammed bin Salman is apparently in control but it is a strange and fragile sort of control that requires the imprisonment of dozens of senior businessmen including members of the royal family, the concentration of power in the hands of one individual and a huge international PR campaign to persuade the world that MbS is a modernising liberal.

That is certainly not the view held in Yemen or across the Middle East. Behind the grand plans for a new $500bn city (sorry, "urban metropolis for the world") run by robots and the radical notion of allowing Saudi women to drive for the first time is a degree of old-fashioned religious fanaticism directed against the Shia communities across the region and Iran in particular. This could produce real instability over the next few months.