Transforming the European Union’s truck fleet to electric and hydrogen vehicles from diesel-powered engines could cut oil use by as much as 11 billion barrels through 2050, or more than two years’ worth of imports.

The transition to efficient and zero-emission trucks can spur “consistent” economic growth over the next three decades as spending on oil is cut, according to the European Climate Foundation and Cambridge Econometrics in a report backed by Tesla Inc., Volvo AB and Siemens AG. Europe imports about 89 percent of its oil, most of which is used for transport fuel.

Commercial trucking accounts for 22 percent of EU transport emissions despite making up less than 5 percent of all road vehicles. The European Commission has said that if the heavy goods vehicle, or HGV, fleet doesn’t start making its rigs more efficient, emissions will grow 10 percent by 2030.

The European Automobile Manufacturers Association said there were about 6.2 million trucks on EU roads in 2015.

Simply implementing more efficient diesel engines in the short term could reduce carbon dioxide emissions by 30 percent a kilometer by the late 2020s, according to the report. Using a fleet entirely powered by batteries and hydrogen could potentially reduce emissions from around 800 tons of carbon dioxide a year in 2015 to 102 tons in 2050.

Cleaning up truck emissions will help Europe reach its emissions targets laid out in the Paris agreement and manufacturers are close to coming up with solutions.

Tesla unveiled in November its first electric truck, the Semi, which can haul a maximum vehicle weight of 80,000 pounds, the standard size for long-haul shipping. It will travel about 500 miles (805 kilometers) on a charge. The company expects to deliver production models next year.

While electric and fuel cell trucks will certainly curb pollution, it’s not clear the industry is keen to jump headlong into transforming its fleet. Concerns over range and infrastructure abound.

“We fully support a transition to cleaner trucks but it has to be gradual,” said Paul Allera, a technical director at the U.K.’s Road Haulage Association. “We have to think about it further as the technology and the infrastructure isn’t right for heavy commercials. It is going to come but we can’t say it will be here in 10 years.”

In a scenario where the EU is deploying more efficient combustion engine trucks and integrating a fully electric fleet the bloc would reduce the amount of oil and petroleum it imports by one billion barrels of oil equivalent by 2030. That will increase to 11 billion barrels by 2050 should the entire truck stock run on zero emission vehicles, according to the study.

“Electrification of trucks in Europe will be paramount for reaching the Paris agreement and it is reassuring to find that this change will not only bring about great environmental benefits but also gains in GDP and jobs,” said Anders Berger, director of public affairs at Volvo Group.

However, in order to achieve an emission-free truck fleet, the report predicts that as much as 140 billion euros ($162 billion) will need to be spent on new energy infrastructure to make it a reality.