In its recent publication, 2012 The Outlook for Energy: A View to 2040, the company predicts hybrids will become a mainstream part of the global fleet, which is to double in size over the next 30 years as car ownership in developing markets grows rapidly.  

By contrast, it predicts plug-in hybrids, electric and alternative fuel vehicles will grow to around 5% of the total vehicle fleet, held back by large up-front costs and a long payback period for money saved in fuel costs.

But while it predicts 90% of vehicles will still run on petroleum-derived fuels by 2040, ExxonMobil said it was expecting demand for fuel to peak and then decline as personal transport becomes more fuel efficient. This, in turn, would be driven by government policies mandating fuel economy for vehicles.

In addition to more advanced technology, the company added that more than a third of the total fuel economy improvements would be as a result of consumers downsizing to smaller cars, with manufacturers improving their conventional engines too.

By 2040, ExxonMobil predicts conventionally powered vehicles will have fallen from a 98% to 35% of new car sales, representing half of the total vehicle fleet.