SIEMENS

Imagine millions of electric vehicles in parking lots and garages, each drawing power from the grid. Now take the thought one step further and imagine each vehicle returning some of its stored energy to the grid during periods of peak power demand. That's the vision that is set to transform the automotive industry over the next few years. It's a vision that is not possible with the internal combustion engine. However, it can be achieved with a bidirectional battery that can be charged up or used as an energy source.
This vision of electric mobility has come about as the result of the convergence of a number of factors. An increasing number of people want to be mobile, while energy consumption is rising dramatically, especially in emerging markets such as India and China. In the past, these demands were met mainly by using fossil fuels. And indeed, for over 100 years cars have been powered by combustion engines while electrical power has essentially been produced by burning coal or natural gas.
Time is running out, however, because fossil resources are being depleted, and the CO₂ emissions they produce are accelerating climate change. More and more energy suppliers are therefore utilizing renewable and CO₂-free energy sources, such as wind and solar power. The problem here, however, is that their yield depends on the weather. As the share of electricity from such sources increases, so too does the need to develop interim storage facilities whose energy can be tapped at a moment's notice. One idea is to use batteries in electric cars, which, depending on demand for electricity and price, can either be recharged from any power outlet or return electricity to the grid. If, for example, a surplus of electricity is available, as is often the case at night or during periods of windy weather, prices could be lowered, making it attractive to "fill up" at such times. Conversely, if winds were calm, or a lot of electricity was being used during the day, the price might rise accordingly, which would lead many vehicle owners to sell their electricity back to the grid at a profit.
In fact, an intelligent management system installed in each car could even make the decision itself, provided it knew how far its driver planned to travel that day, and how much electricity the battery would require for that distance. In any case, most cars sit idly for most of the day, which means they could be continually connected to the grid from their office parking spaces, parking lots or home garages. Flexibly determining electricity prices in accordance with supply and demand would also eliminate any problem associated with many vehicles trying to recharge at once, which of course would cause prices to skyrocket.

Cars that Generate Income. The rule of thumb is that there should be some 300 electric vehicles as potential energy storage units for every wind turbine with a peak output of three megawatts. The existence of cars as mobile storage units would kill two birds with one stone. Assuming vehicle batteries could handle numerous charging and discharging cycles, energy supply companies would be provided with a buffer against surplus energy from renewable sources, while vehicle owners would have a source of income to help them finance their relatively expensive batteries.
In the foreseeable future, batteries will remain one of the most expensive components in electric cars. Achieving a range of 100 km for a mid-sized vehicle today requires a battery with approximately 15 kWh of energy content. Such a battery currently costs more than €10,000. However, there are other options for such mobile power plants besides having them financed through income from electricity. For one thing, vehicle owners wouldn't necessarily have to buy the battery. Instead, it could be leased from an energy supplier. In other words, an energy company would decentralize its energy storage capacity and finance the battery through the latter's "secondary use."
Regardless of what form electric cars may take, and what role they will play in the electricity mix, any future concept will need to incorporate the most important stakeholders: electricity producers, automakers, suppliers, and governments, whose policies should pave the way for the necessary paradigm change.
In Germany, a first step was taken in November 2008, when the Ministry of Economics and Technology (BMWi); the Ministry of Transport, Building, and Urban Affairs (BMVBS); the Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU); and the Ministry of Education and Research (BMBF) held a National Strategy Conference on Electric Mobility. The conference brought together energy suppliers such as E.ON, RWE, and Evonik; automakers and suppliers such as Volkswagen, Daimler, Continental, and Bosch; electrical and electronics companies such as Siemens; and various research institutes. "My goal is to utilize electric mobility to help achieve a breakthrough for a new culture of mobility and a new system of urban planning," said German Transport Minister Wolfgang Tiefensee at the conference. Environmental Minister Sigmar Gabriel added that electric cars acting as buffer storage units would establish an important link to renewable energy sources.
Such a development will become important in Germany, Gabriel said, because the country plans to increase the share of renewable energy sources in its electricity mix from around 15 % today to as much as 40 % by 2020. Secretary for Economics and Technology Dagmar Wöhrl added that it is essential for utilities to work closely with automakers, as extensive R&D investment will be required — particularly in the fields of energy storage, vehicle engineering, and power-grid integration.
In fact, such alliances are already in place. For instance, BMW, Daimler and Volkswagen are working with major German power suppliers such as Vattenfall, RWE, and Evonik. VW also recently began working with Toshiba on the development of battery technology. Powerful batteries are indeed the key to the entire vision, which is why their development has to be supported, said Thomas Rachel from the BMBF.
A total of €500 million could be spent on mobility research over the next three years within the framework of the German government's stimulus programs. Activities here could include the development of an appropriate infrastructure and all aspects of electric vehicle technology. Regardless of how the details turn out, conference participants emphasized that the overall goal is to make Germany the leading market for electric mobility.

Battery Alliance. Germany is already leading the way when it comes to electric mobility components for supplying energy or manufacturing electric automobiles. The country designs the most efficient power plants, whether conventional, wind powered, or solar-thermal — and has also developed systems for low-loss power transmission over great distances.
As far as automobiles are concerned, Germany remains a leader in electric motors and vehicle electronic systems. However, the situation is different with regard to battery technology. Here, most new developments are taking place in China and Korea; only around 1 % of all lithium-ion batteries are manufactured in Germany. Still, Germany has produced some new developments, as evidenced by the fact that a team of three scientists from Evonik's LiTec subsidiary was nominated for the German Future Prize two years ago. The team developed a separator for lithium-ion batteries that prevents short circuits, thereby making the high-performance units much more reliable. This is important because lithium-ion cells are regarded as being the only batteries capable of powering electric cars. Basically, they are the only batteries that can deliver the power density required for automotive transportation. The BMBF has thus established a "Lithium-ion Battery" alliance that will allow Germany to catch up in this field.
At the same time, the BMWi has launched a "Mobility and Transport Technology" research program to develop state-of-the-art drive systems. Here, in addition to hybrids, the focus is on new power electronics systems for automobiles. A good electric vehicle requires a battery with an energy content of 42 kWh to achieve a range of around 300 km — in other words an energy consumption level of 15 kWh per 100 km. Assuming a normal voltage of 230 V and a current of 16 A, it would take around 12 hours to completely charge such a battery. "But at 400 V and 25 A, a driver could recharge in just two hours," says Professor Gernot Spiegelberg, who heads an electric mobility team at Siemens Corporate Technology. Every German household has 400-V potential because that's the voltage used by a normal three-phase current connection. "The only thing missing up until now has been a suitable interface between vehicles and the grid," he adds.
Spiegelberg's team, which works closely with Siemens' Energy and Industry Sectors, is the hub for the company's electric mobility research and development effort. The team's focus is on electric vehicle system requirements and the design of a mobility power grid infrastructure. Among other things, Siemens engineers are examining power generation and distribution options, transport and energy management systems, smart metering, power electronics, software, sensors and, of course, electric drives and the recovery and storage of energy. In addition to serving as energy storage units, electric drives could also become an important part of Siemens' Environmental Portfolio. That's because they utilize energy more efficiently than combustion engines.
"I believe that in Germany alone, there is potential for 4.5 million electric vehicles on the road by 2020," says Spiegelberg. "All of these vehicles could get their power from the existing grid. And that's just a conservative estimate, because these vehicles would only add up to about half of the second cars owned by families, most of which never travel over 70 km a day." As a consequence, one out of every ten vehicles in Germany would no longer use gasoline.