LONDON: Global energy demand will surge by a third over the next two decades on advancing prosperity, but Indian demand growth will eclipse that of flagging giant China, Britain's BP forecast Thursday.

"The demand for energy is set to increase significantly driven by increases in prosperity in the developing world," BP said in its Energy Outlook 2019 for the industry.

"This improvement in living standards causes energy demand to increase by around a third over the outlook."

China and India will together account for more than half of the growth in energy consumption during the forecast period, according to BP.

However, Chinese demand growth will be hit by the superpower's economic slowdown and is expected to be outpaced by India.

"China's transition to a more sustainable pattern of economic growth means that by the mid-2020s India surpasses China as the world's largest growth market, accounting for over a quarter of the growth in global energy demand over the outlook," it said.

"Even so, China remains the largest market for energy: roughly double the size of India in 2040."

China will remain the largest source of growth in energy supplies, driven by rapid expansion in renewables and nuclear power, but its appetite will be sapped partly by efficiency measures.

BP added: "Some of this decline (in Chinese energy growth) stems from policy efforts to improve the efficiency of existing industries.

"In addition, it reflects the continuing transition of the Chinese economy away from energy-intensive industrial sectors towards less-intensive service and consumer-facing sectors."

World oil demand growth was meanwhile set to grow for the first part of the outlook, met by booming US shale oil production.

However, it was then expected to plateau as US shale output declines and OPEC oil production recovers, according to BP.

Global gross domestic product was expected to more than double by 2040, aided by growing prosperity.

BP stressed however that two thirds of the world's population will still live in nations where average energy consumption per head is relatively low, highlighting the need for more energy.