Electric Cars as Energy Reservoirs

The generation principle pursued by the energy sector in recent years and decades was demand-driven. This means that a power plant only produces electricity when the customer needs it, i.e. in line with demand. Conversely, renewable sources of energy such as wind power and solar power are not available "on tap," as they depend on wind intensity and sunshine duration.

As renewable energy sources constantly increase their share of total electricity generation, the task at hand is to find ways to bring demand more in line with supply.

E-mobility is ideally suited to this, because cars are parked most of the time. Once mass produced, electric vehicles could be linked up to the grid and let their batteries be used as distributed power reservoirs.

In periods of high electricity generation from renewables such as sunshine, power would be fed into vehicle batteries. There are two ways to use this electricity thereafter-as "fuel" for the car, or as a "reservoir" that feeds it back into the grid if so required to meet demand.

E.ON is promoting the market launch of electric vehicles on the strength of a series of projects and activities. We intend to capitalize on the use of electricity to help make transport cleaner and less dependent on fossil fuel. The more vehicles are powered by electricity, the less modern transport will fully depend on oil.

This is why we are addressing all major aspects-from the environmentally friendly generation of the required electricity to the convenient "filling" of vehicles with electric power.

Munich Cars Powered by Green Electricity

MINI E cars have been roaming the streets of Bavaria’s capital and neighboring rural districts with E.ON power since July 2009. E.ON’s part in the project also involved building a network of public charging stations, while ensuring that the test participants can recharge their electric cars both at home and close to work.

E.ON is providing all of the electric cars included in the field trial with electricity-preferably generated by hydroelectric power stations without emitting carbon dioxide.

In so doing, we are proving that zero-emissions e-mobility is already possible. But we are also aware of the fact that it still faces a long road to mass production. We intend to pass a milestone en route to achieving this goal with this pilot project. In addition, we want to collect experience: Where do our customers want to charge their electric cars? How do they use them? What products and price plans do we need?

The "Electric Mobility Fleet Test"

E.ON joined forces with Volkswagen, the German Environmental Ministry and other partners in June 2008 to work on the "Electric Mobility Fleet Test." Our objective is to explore the commercial opportunities offered by charging large numbers of electric cars using the existing power grid by 2010. The trial is designed to make use of vehicle batteries as power reservoirs within the electric grid in the near future. If it succeeds, electric mobility will be able to make an important contribution to storing electricity generated from renewables (which fluctuates at times), thus improving its usability.

E.ON further plans to determine the adjustments that must be made to existing distribution networks to ensure that security of supply remains guaranteed in the future as well-even if millions of electric cars need to be charged.

The test car is a Golf TwinDrive-a seemingly stock Golf on the outside, but a low-emission hybrid car on the inside. The TwinDrive uses an electric motor for zero-emissions city driving and short trips. Its lithium-ion batteries can be recharged via standard outlets, making it a plug-in hybrid. The diesel engine takes over on long hauls and when the battery is empty. At least 20 cars should be on the road using this technology by 2010.

Cableless: Inductive Charging

Inductive charging is already standard on electric toothbrushes and transport robots used in production facilities. Electric vehicles could also benefit from the user-friendliness of no-contact charging.

It would eliminate the need for cables used to hook cars up to charging stations in rain, sleet or snow-cables that are easily tripped over. With inductive charging, all you would have to do would be to park the car and wait for the charge to complete.

The concept involves embedded coils, which transmit electricity to the car battery cable-free. Parking spots featuring this technology commence the charging process automatically, as soon as the car has identified itself-also via a wireless link. Transmission losses are kept to a minimum under ideal conditions. Adapting and optimizing inductive charging to electric vehicles is one of E.ON’s goals.

It is important to not only test and refine the method early on, but also to create standards and adapt existing regulations to current needs. E.ON promotes research in the field and is already subjecting inductive charging to daily tests on a daily delivery van equipped with an electric drive.

Experience amassed in the process will be built upon in close cooperation with industrial partners from development to mass production. And by the way, the magnetic field created during inductive charging is monitored by safety systems and is thus completely harmless to both humans and animals. Parking spots equipped with this technology can supply power to electric cars without cables-thanks to inductive charging.