Electric cars were first invented in the late 1800s and remained popular into the early 1900s, before being displaced by vehicles with internal combustion engines. Electric and hybrid vehicles then experienced a dramatic resurgence at the end of the twentieth century due to concerns about air pollution, global warming, and dependence on fossil fuels. Cars such as the Tesla and Toyota Prius are now a relatively common sight in certain parts of Western Europe, the United States, and Asia.
However, there are key obstacles to electric vehicles taking off everywhere and contributing to dramatic improvements in air pollution levels and climate change. These include battery cost and size, and how far the cars can travel before needing to recharge. Another major problem worldwide is the lack of sufficient infrastructure for recharging thousands of electric cars, on top of existing domestic and commercial power demands.
Uncontrolled, high penetration by electric vehicles could have a disastrous effect on a local power grid. They are low-energy but high-power – i.e. when they are plugged in, the power demand is high like that of a house but over a short period of time. If the cars are all connected at the same time of day, such as after people return from work, this can create a massive bump in demand that it is both difficult and expensive to meet.
Power system engineers research different ways in which to respond to this potentially crippling phenomenon, by managing and reallocating bumps in demand. Modelling suggests that careful management of the introduction of a large fleet of electric vehicles – for example 20,000 cars added to the power grid of the French island of Guadeloupe – could not only mitigate any negative impacts but also be harnessed to achieve a variety of benefits .
A five-month analysis of the potential impact of introducing electric cars to Guadeloupe explored whether the effects of spikes in demand could be mitigated by fleet aggregation. Such strategic balancing of a local power grid would reallocate the daily power demands from a fleet of electric cars so that the grid could cope, but might also be able to produce additional benefits. These could include greater stability of power reserves and improved integration of renewable energy sources such as solar and wind power.
The sophisticated modeling conducted during the research assumed the presence of a smart grid, with meters constantly monitoring the levels of power demands in homes. A statistical model was developed to incorporate the effects of people’s driving patterns into this picture – from everyone charging their cars at night after a day of use, to the charging being interspersed with up to four trips a day. Additional variables included different speeds of charging, from 30 minutes to 1.5 hours. Incentives such as different pricing might also convince consumers to charge their electric cars at certain times of day.
Studies such as this suggest that strategic management could help local power grids to adjust to the large-scale introduction of electric vehicles. That could take us one step closer to a future with sustainable transportation, powered by cleanly generated electricity rather than by polluting fossil fuels.
Alexi BAKER & Guillaume GUERIN, R&D tax consultant, Leyton UK
 Guillaume Guérin and Richard Bucknall, “High penetration of electric vehicles in an isolated grid: a study in Guadeloupe” , presented at the 16th International Conference on Environment & Electrical Engineering (ICEEE) in Florence on 8 June 2016.