Millions of mobile storage systems
- The Vehicle to Grid concept suggests a perfect symbiosis with wind power.
It’s still a flirtatious vision but wind energy and electric cars could become a match made in heaven: Batteries recharging when other demand on the grid is low, returning the stored energy back into the grid when demand on it is high.
By Nicole Weinhold, photographed by Daimler
Every day 191 million cars run on US roads. If under all that steel they concealed batteries brimming with electricity instead of tanks full of petrol or diesel fuel, they’d clock in a total capacity of 2,865 gigawatts (GW). That’s 686% of the average power plant capacity in the entire United States, which amount to 417 GW. The guzzlers move for only ane hour a day on average. The other 23 they are parked idly – in the home garage or in the parking lot at work. During that time they could be charging their batteries or conversely feeding energy into the grid through a power socket.
This little mental image brainstormed by American scientists Willett Kempton and Amardeep Dhanju is the result of their studies on storage of large amounts of wind energy, the kind that could be generated by offshore parks in future, for example. The University of Delaware scientists wondered whether building big wind power storage systems is necessary and have come to the conclusion that in the long term, batteries in electric, hybrid and fuel cell automobiles could do that job. In fact, it’s feasible that there needn’t be as much upscaling of the power grid as now being discussed to accommodate the transmission of wind energy. The Vehicle to Grid (V2G) concept suggests a perfectly dreamy symbiosis with wind power, especially because in terms of fluctuations in wind power generation it kills two birds with one stone. Firstly, the energy would be used to charge the batteries specifically in times of low power demand. Windgenerated electricity wouldn’t have to go unused at night, for instance, and no turbines would have to be down throttled to avert overload. Secondly, the batteries could function as mini load balancing power plants during peak consumption by feeding the stored wind electricity back into the grid. And most importantly, so-called plug-in vehicles could cut road transport’s high fuel consumption and carbon dioxide output.
Enercon sees an opportunity for wind power
Ten years ago US scientist Kempton published an article entitled “Electric Vehicles as a New Source of Power for Electric Utilities”. For a long time, though, the idea found no followers, not in the US, nor in Germany. The German government invests billions in the development of fuel cell technology, but so far not much has happened with plugin technology. At least Germany’s electricity industry association, Verband der Elektrizitätswirtschaft (VDEW), has spotted the opportunities and according to Mathias Samson, of the Environment, Traffic and Transport division of the German Environment Ministry (BMU), introduced a concept on the topic. “Beyond that we’re holding talks with the automotive industry,” he reports. Samson says the issue didn’t figure largely in the past, especially since batteries were hardly suitable due to their low travel range (see page 36).
For visionary Aloys Wobben the rather meagre interest in the subject was no reason to close the door on battery research. As head of wind turbine maker Enercon he’s been sounding the opportunities for wind power usage for years. In 2002 he presented some facts to a prominent visitor, Sigmar Gabriel. For a distance of 50 kilometres an electric powered car needs about 11 kilowatt-hours. The annual energy yield of one 1.8-megawatt (MW) Enercon turbine could power some 900 such cars, he ex plained to Gabriel, who was then Premier of Lower-Saxony and is now Germany’s Minister for the Environment, Nature Conservation and Nuclear Safety in Chancellor Angela Merkel’s cabinet.
It would require, of course, charging stations, ideally in every garage and every parking lot. Now there’s movement in that direction. In December 2006 British company Elektromotive Limited based in Sussex installed the first two charging stations for plug-in vehicles in London. The company says that 200 more are to follow, particularly at London supermarkets and cinemas, by February next year. Key to the market opportunities of the electric dream on wheels is acceptance. For years Enercon has been working on a battery-powered Audi A4 – a somewhat unusual format for an electric car, but in Wobben’s opinion the vehicle should break the mould of the stereotypical batteryoperated mini car. His motto is that a battery electric vehicle has to be neither small nor slow. The A4 is already regularly used to chauffeur political bigwigs and the Enercon boss himself used it to attend the energy summit in early July. Series production, however, will take another two years.
Many new research projects
Sweden’s wind energy association, Vindkraftens Investerare & Projektörer (VIP), also reckons with substantial potential for wind power in road transport. According to VIP head Matthias Rapp, the association recently commissioned a study of future applications of wind power in the country. The reason being that the Swedes have to seriously scale up to meet their EU climate protection targets by 2020; not much more can be done with hydropower and biomass. So wind energy is surfacing as one of the most crucial resources. “If we concentrate only on electricity production,” says Rapp, “wind power must soon replace other capacities.” But actually the power plants aren’t in a condition to necessitate that, he adds. In road transport, by contrast, the need is great. “The automotive industry could be the best taker for wind-generated electricity.” With hybrid vehicles the wind power could be used in Sweden instead of being exported. The results of the study, in which car makers Saab and Volvo were also involved, are expected in April 2008.
There’s still plenty of need for research. Aleksandra Bukvi´c-Schäfer is familiar with the weak spots. The director of energy storage technology at ISET, Germany’s institute for solar energy technology in Kassel, confirms that battery technology so far isn’t up to demands. But, she says, “a good deal of development has happened very recently”. The cost of batteries is another problem. Tomi Engel of the committee for solar mobility at the German section of the International Solar Energy Society has some concrete suggestions. He says it’s key that the costs of batteries are not passed on to car buyers. Energy utilities and automobile makers could cooperate, for example, in that the utilities assume the initial costs if they in return automatically get the power supply agreements for the electric vehicles. The power would naturally flow both ways. Engel recommends “an electricity metre in every car”. Then the car owner could also be remunerated as a supplier of load balancing power when he feeds expensive, refined electricity into the grid. Another important instrument, according to Engel, is the price of carbon dioxide. In other words, CO2 polluters ought to be taxed accordingly and clean car technology should be rewarded with tax exemptions. Engel doesn’t believe that electric vehicles will make their great breakthrough anytime soon. For him it’s more about promoting the technology so that it gets its chance in 10 to 15 years. “We’ll start with a small number of cars,” he says, adding that the supplier industry isn’t up to any great leaps, anyway. To equip a million cars, battery production would have to increase by five times the current worldwide output. “If we really begin promoting the technology now, perhaps we’ll have a million cars in ten years,” he says.
According to Bukvi´c-Schäfer the problem of costs is joined by the issue of the cars’ operating distances. Besides higher charging cycles, a “very intelligent energy management strategy” is necessary. “The system would at first have to learn the owner’s route usage.” This area has been researched for some time. RWTH Aachen’s institute of automotive engineering (IKA) is involved in an electric vehicle test fleet project sponsored by the European Commission, in which the transmission system’s lifespan and reliability are under investigation. Beyond that, the institute is observing sociological aspects, such as charging behaviour and acceptance amongst car users. It’s important, for instance, for the battery to recharge when electricity is inexpensive. Other than that it of course should not supply energy to the grid shortly before a journey. The diffi culties and problems entailed with these demands, says Bukvi´c-Schäfer, can’t be underestimated. To her “using electric vehicles as mobile storage systems is, so far, still just an idea for the future”.