Chinese and European companies are advancing green vehicle technology amid signs of modest momentum in retail sales in a low oil price era.

Forecasts from IHS Automotive find global auto sales for 2015 will increase 2.5 percent from last year, which would be five straight years of growth if predictions are accurate. China is expected to the lead the growth in sales for the year.

For Hanergy Holding, a Chinese solar power company, the future is in green technology.

"There are currently only 400,000 electric cars in the world, but the market is expected to hit 10 million by 2020," Chairman Li Hejun said Monday.

The chairman said his company would play a role in the development of five new models of solar-power cars by October. Last month, Hanergy acquired U.S. rival Alta Devices.

Nevertheless, IHS expects sport utility vehicles will be the fastest-growing segment in China, with sales expected to surge by 26 percent year-on-year.

In Europe, German energy company RWE said it was supplying technology for electric vehicles for its automotive counterpart Volkswagen. RWE director Norbert Verweyen said partnering with Volkswagen would move the electric vehicle market forward.

"The convenience of being able to recharge in almost any location is the prerequisite for convincing people of the merits of electric mobility," he said in a statement.

IHS forecasts said it expects the bear market for crude oil, and the subsequent low price for fuel, will present challenges to the auto industry.