EV fleets are expanding at a fast pace in several of the world’s largest markets. This is being driven by governments and automakers who are promoting electricity powered vehicles as a key technology to curb oil use, fight climate change and air pollution.

As more renewable energy sources are used, power systems must become more flexible and adjustable to balance supply with demand. To achieve this, services have required that span from fractions of a second to seasonal time scales. Solar and wind power will become increasingly critical, but their intermittent nature will result in nearly twice the annual variability in residual demand compa