BERLIN, (Reuters) – Mercedes-Benz aims for electric vehicles that consume as low as 10 kilowatthours of energy per 100km (62 miles), according to its chief technology officer (CTO). This is a third higher than the average electric car.

Markus Schaefer CTO stated that electric cars have a limited range and efficiency is the key to maximum performance. He spoke as the manufacturer celebrated the test drive of its EQXX vehicle prototype over 1,000 km, from Sindelfingen in Germany up to the Cote d’Azur.

Schaefer stated that first we optimize efficiency and then we can determine how many batteries we need to fit in our cars. He also said that customers should have the ability to choose the right size battery for them based on what they require.

Automobile manufacturers from Mercedes-Benz, Tesla (NASDAQ:), to China’s NIO (NYSE:) have been in an intense race to build higher-range cars to dispel consumers anxiety about the absence of widespread electric vehicle charging infrastructure.

Mercedes’ Vision EQXXX prototype was unveiled in January. It boasts a range of 1,000 kilometers and a battery that is half as large as its flagship EQS. Mercedes also promised in January that parts of this car would be made into series cars in between 2 to 3 years.

Mercedes-Benz claimed that the car used 8.7 Kilowatt Hours of Energy per 100 Km on its 11-and-a-half-hour drive to France. This was twice the efficiency of other Mercedes-Benz models and Tesla’s long-range Model S 60.

According to car comparison portal carwow the Mercedes EQS offers the longest range of any car on the market with 768km, while Tesla’s Model S Long Range has up to 652km.

Schaefer indicated that there would be another increase before falling, but declined to give details about the range Mercedes is targeting for future models.