The US has cemented its status as a net exporter in world oil markets, a sharp reversal from past years that could affect its ties to foreign allies. The top oil producer and consumer exported 89,000 more barrels of crude oil and refined petroleum products a day than it imported in September, the first full month of a positive oil trade balance since the 1940s, the Energy Information Administration said Friday. Imports exceeded exports by 12m barrels a day a decade ago.

A variety of factors contributed to the shift: surging production from shale oilfields, the end of a crude oil export ban in 2015 and fuel economy improvements for cars that limited petrol demand even as highway travel rebounded from a recession. Along with rises in natural gas output and renewable electricity generation, the oil shipments have pushed the US towards a long-invoked goal of energy independence, according to Rystad Energy, a consultancy.

A US petroleum trade deficit of $62bn in 2018 –   10 per cent of the country’s trade balance –           is on track to become a surplus of hundreds of billions of dollars “thanks primarily to the gargantuan rise of output from the US shale sector”, the consultancy said this week.