Connecting wind farms to national power grids is often an expensive and fairly complicated process. An R&D project is looking into the possibility of connecting wind farms to existing railway power grids instead, as a lower-cost option.
Wind power is a priority for Vattenfall, and the company plans to invest SEK 26 billion in new wind farms before 2015. In some cases, even when wind conditions are favourable, planned wind farms may have to be cancelled because of difficulties encountered when attempting to connect the farms to the power grid.
“In these cases you might have to construct a 20-30 kilometre overhead line to connect the wind farm to the grid,” explains Fredrik Carlsson, Senior R&D Engineer. “It might be difficult to get the authorities to approve that, and a cable is a very expensive alternative.
“In some places it might be possible to connect the wind farm to the railway grid instead. We are evaluating the costs and benefits of investigating technologies for connecting wind farms to railway grids.”
In Norway, a few hydropower plants are connected to the railway grid, but Carlsson has never heard of a wind farm being connected to a railway grid.
“There are some technical issues regarding connection of a wind farm to the national grid,” he says. “If you connect a wind farm to a railway grid the wind turbines must be constructed to meet the demands from the railway grid.”
The R&D project is in the very early stages and feasibility studies haven’t been initiated yet.
“We already know that it is possible to feed electricity from a railway grid to a national grid, but there are several technical issues that have to be carefully studied now,” Carlsson says. “Our overall goal is to lower costs for grid connection.”