Electric cars and wind energy storage
Samso, move over – hello Bornholm!
A few years ago, as a 10-year experiment aided by tax breaks and government incentives, the Danish island of Samso changed all of its energy sources until its carbon footprint not only shrank to zero, but went into the negative numbers. Eventually, through wind, solar, and even straw-burning methods, the island produced so much of its own energy in a green and sustainable way that it had an excess supply, and began exporting it to the grid on the mainland.
The one thing the Samso residents couldn’t seem to do, though, was find an economic way to operate vehicles that didn’t guzzle gas. So they added extra green elements to their energy production, to offset the footprint of that one emission problem they couldn’t seem to solve.
However, another Danish island, Bornholm, may be about to show Samso how it’s done. With Denmark set to build an extensive electric car battery charging and swapping infrastructure all along its major roadways, Bornholm will participate in that project but add an extra twist: using electric car batteries to store excess wind energy.
At the moment, the island gets 20% of its power from wind turbines, yet there are enough turbines there to provide as much as 40%. The main reason Bornholm isn’t using its turbines to capacity is simply a matter of storage: there’s nowhere to put the excess energy when the wind is really blowing. All the turbines can operate on a normal day when there’s nothing but breezes and short gusts. But build up to the wind speed of a big storm, and all that extra power has nowhere to go. So right when the wind turbines should be operating in all their glory, the island has to turn many of them off, to avoid blowing the whole system.
For quite some time, proponents of green energy have talked about the idea of using parked electric cars as storage facilities when excess energy is created that fills the grid system to capacity and threatens to overload it. With this system, known as “vehicle-to-grid” or V2G, the extra power could be siphoned into the car batteries, and when the wind dies down, could then be fed back into the grid as needed. Most of this power would not even be energy used to make the vehicles travel, but would be destined for the larger power system.
The process has never been tried before, but now Bornholm will be the pilot project, in the same way Samso was a decade ago. IBM’s Zurich Research Laboratory has been developing software that will be used to control the system. It will operate much like other software that monitors and manages supply and demand for power grids, but with the extra factors involving the turbines and car batteries. If the V2G method works well, Bornholm may be able to add enough new turbines to its infrastructure to provide up to 50% of its total energy needs, rather than the current 20%.
By making Bornholm a microcosm of the mainland’s battery charging project, Denmark will not only be getting a good idea how well that infrastructure itself will work. It will also be testing ways to gather more power from wind turbines, and make more efficient use of all that energy just flying around out there.
