The Nio EP9 self-driving concept electric vehicle was displayed during the media day of the 17th Shanghai International Automobile Industry Exhibition on April 19, 2017, in Shanghai, China. The electric vehicle market is still small, but it has raised big questions about the future of gasoline demand.

Morgan Stanley analysts issued a forecast that global miles driven will rise to 32 trillion by 2030, up from 11 trillion currently, with emerging markets a major driver. They say that outlook is not only bullish for electric cars and light trucks but also for gains in gasoline-fueled vehicles. For example, they expect China, the largest and fastest adopter of electric vehicles, to increase miles traveled to nearly 9 trillion by 2040, up from 1.5 trillion currently. "Even allowing for an aggressive penetration of EVs, we forecast gasoline demand for light vehicle transport to roughly triple by the mid-2030s before beginning a slow decline," the analysts wrote. "It's little wonder why the Chinese government is so focused on encouraging the development of a sustainable electric transport ecosystem on the grounds of energy security and environmental sustainability."

Last year, electric cars and light trucks, including hybrids, displaced only about 50,000 barrels per day of oil in a world that is using 100 million barrels per day for the first time this year, according to IHS Markit. That's small, but energy experts say that when combined with other trends, such as fuel-economy standards, the reduction in oil demand will start to add up. "We have electric vehicles reaching 30 percent of new-car sales by 2040, up from 1 percent now," said Jim Burkhard, who heads oil research and energy and mobility research at IHS Markit. Last year, he said there were 2.8 million electric cars on the road compared to 1.5 billion oil-fueled vehicles, and electric vehicles could reach 36 million by 2025. "Each year it will impact more and more. There's no doubt about that, but the bigger demand story is fuel economy. EVs on their own are not disruptive," he said. He said global fuel-efficiency efforts alone should result in savings of 18 million barrels a day of fossil fuels by 2040.

Disrupting a global market: Ridesharing is what could be disruptive for the traditional car market, and so could self-driving cars. When Uber and Lyft operate self-driving fleets of electric cars, that will make a dent in gasoline demand. "About a third of global oil demand comes from cars, and 40 percent of the growth since 2000 has come from cars. So what happens with cars is going to have a big impact on oil demand," said Burkhard. In a recent report on electric vehicles and energy, the World Economic Forum said automated vehicles could ultimately be 40 percent cheaper to drive per mile than a vehicle with an internal-combustion engine. "Mobility service companies, especially with driverless technology—that's where electric vehicle sales could have a commercial footing," said Burkhard. "We think the first driverless car services will start to materialize in the next year or two. It's not 10 years from now. If that grows and people accept it and the public gains confidence in it, adoption will increase quite a bit over the next decade."

IHS Markit hosts the annual CERAWeek energy conference in Houston next week, where electric vehicles and the future of transportation will be a major topic. Morgan Stanley analyst Adam Jonas, who authored the report and has been bullish on Tesla for many years, will appear on a panel. Morgan Stanley's analysts said they believe miles driven globally will rise because the cost of driving will drop due to shared mobility and automated technologies.