Preventing EV Charging Blackouts
One fear that some skeptics have about the wide-spread adoption of electric vehicles is our electric grid’s capacity to handle charging all these vehicles at once. The thinking goes, if everyone gets home at night and plugs in their electric car at roughly the same time, the entire street will go dark.
As part of a research project, Audi collaborated with IT service provider GISA GmbH, and other partners, to simulate this “overload” scenario on a local power grid: multiple electric cars charging simultaneously, and with high power, on a street supplied by a local network transformer. It used its findings to develop an answer to the problem – intelligent and “grid-optimized” charging that dynamically manages the electrical load between all of the vehicles being charged.
Preventing Grid Overload
Grid-optimized charging is designed to counteract this scenario through the intelligent management of charging procedures and thereby prevent a grid overload. Dynamic management of the charging procedure of each vehicle is achieved through electronic communication between the car and the grid.
In practice, while grid-optimized charging will increase the average charging time for each vehicle – in order to manage the total electrical load for the transformer – intelligent programming, taking into account the set or average departure times of each vehicle, should result in no additional inconvenience. On a level 2 charger, most EVs do not need the entire period between arriving home in the evening and your departure in the morning to charge; grid-optimized charging can ensure your vehicle is still fully charged when you need it. Simply ensure your desired time of departure is set in your vehicle.
At the end of the day, Audi’s research showed a win-win situation on streets where total capacity was an issue. The electric cars were still able to use their downtime to fully charge with dynamic charging capacity adjustment – while also ensuring the power grid was never overloaded. Drivers’ mobility needs weren’t impacted at all.
How Does It Work?
Clever new electronic modules in the domestic power grid allow the house, the electric car, and the grid to speak the same language.
The central component is what is known as a smart meter gateway (SMGW) – a device that is already mandatory in many countries if a household’s power consumption exceeds a certain threshold. The smart meter gateway establishes a secure data connection between the house and the grid operator via a certified IT back-end. All necessary information and control signals are transmitted in a targeted manner – either to the home energy management system (HEMS) or directly to the charging system in the vehicle. Communication between the SMGW, your house, and an Audi e-tron would allow the charging capacity of the car to be adjusted as required while still charging fully before you depart on your next trip.
Many of the technical standards and communication protocols necessary for grid-optimized charging are already in place. There already exists a standard which describes the exchange of information between the domestic grid connection and the energy industry. In cars, standard data bus protocols serve as the communication protocol. Together, they can connect the participants of the future energy industry on the basis of a common language.
A Bright Future
Further down the road, new networking technology will allow the charging capacity, charging time, and charging duration to be controlled for each car. In addition, grid-optimized charging could save you even more money: if you’re able to charge your car at work as well as at home, the system could be set to charge at a lower rate, getting power from your provider at a discounted price.
Intelligent charging of electric cars is an important element of the sustainable energy industry of the future, and Audi and other automakers are working hard to ensure that everyone on your street can plug in safely and conveniently without causing any disruptions.