The idea of storing excess wind energy as hydrogen is picking up steam in Germany, with plans for a second pilot program popping up – this one from the big power company E.On. But there’s a key difference between the two projects: In Herten, Germany, the company Hydrogenics plans to use power from a wind plant to electrolyze water to produce hydrogen that will be stored and later used in fuel cells to provide power. E.On also intends to use wind to produce hydrogen by electrolysis, but then the hydrogen “will be fed into the Ontras gas pipeline system and be used like normal natural gas,” the company said.
One of the challenges with wind power is that maximum production often comes overnight, when power demand is low. Energy developers are taking stabs at different ways to efficiently store that energy. In West Virginia, a big battery system is being employed; and pumped storage is getting increasing attention, including by E.On, which said it was expanding its investments in that area. (With pumped storage, excess wind power is used to move water to a higher elevation, where it can then be stored for later use – with the assistance of gravity – to create hydropower.)
“We need new storage capacities so that we can further increase the share of weather-dependent wind power in our generation portfolio in coming years,” Professor Klaus-Dieter Maubach, E.On’s marger for Technology & Development, said in a statement. “Using the existing gas infrastructure to store hydrogen is a promising approach in the long run, enabling us to combine our strengths as a power and gas company.”
E.On said it was spending more than €5 million ($6.8 million) to develop the pilot plant in Falkenhagen, in northeast Germany. The company said using power from renewable energy sources, the plant will produce about 360 cubic-meters of hydrogen per hour beginning in 2013 through electrolysis.
“At present,” the company said, “up to 5 percent hydrogen can be added to the natural gas grid without any problems, and in the medium term experts expect up to 15 percent. This means that today’s entire renewable power output could be stored in the German gas grid. Demand for capacity on this scale will, however, only arise over the next decades, when most of generated power is coming from renewable energies.”
Hydrogen produced from wind-fueled electrolysis can also be reacted with carbon dioxide to produce what’s being called “renewable methane.” This synthetic methane could go directly into the natural gas pipeline without the limitations of hydrogen. A 25-kilowatt demonstration plant using just such a system is operating in Germany.