Half the electric vehicle market value lies in larger road vehicles, notably cars, and here the legal restrictions are weaker or non-existent, and range anxiety compels most people to buy hybrids if they go electric at all. Over eight million hybrid cars will be made in 2025, each with a range extender, the additional power source that distinguishes them from pure electric cars. Add to that significant money spent on the same devices in buses, military vehicles, boats and so on and a major new market emerges. Whereas today's range extenders usually consist of little more than off- the- shelf internal combustion engines, these are rapidly being replaced by second- generation range extenders consisting of piston engines designed from scratch for fairly constant load. However, a more radical departure is the third- generation micro turbines and fuel cells that work at constant load.