by Greg Klein | March 17, 2017
Should all go to plan, the transformation from dirty to clean energy might come to be symbolized by this German coal producer. A longstanding idea to convert mine shafts to hydro chutes got further encouragement in a March 14 speech reported by Bloomberg. North-Rhine Westphalia state governor Hannelore Kraft has declared her support for a project that would convert the Prosper Haniel coal mine into a pumped storage facility.
Referred to as a type of battery, it would use excess wind or solar energy to pump water from a reservoir at the depths of the mine to another reservoir above the shafts. When wind or solar fails to meet demand, the water would be released, plunging something like 1,300 metres to electricity-generating turbines.
A 2014 article on Grist.org said the mine could store up to about 990,000 cubic metres of H2O, “roughly the volume of the Empire State Building.” That could produce a 200 megawatt capacity, enough to power more than 400,000 homes, Bloomberg reported.
Prosper Haniel’s mining days are expected to end in 2018, when federal subsidies for the industry expire. Other mines could follow this reincarnation as the coal mining region of North-Rhine Westphalia intends to double its production of renewable energy to 30% by 2025, Bloomberg stated.
According to the National Energy Board, Canada’s only pumped storage facility is the 174 MW Sir Adam Beck station operated by Ontario Power Generation, which diverts water from the Niagara River to a 300-hectare reservoir. The transition from turbine to pumping sequence takes just minutes and occurs several times a day, the utility states.
The NEB attributes over 30 pumped storage facilities to the U.S., producing about 23,000 gigawatt hours a year but using about 29,000 GWh to do so. “Despite this net loss of energy, the grid reliability provided by PSH facilities and the ability to generate when demand is strong is highly beneficial and will become increasingly important as Canada and the U.S. integrate more renewable power into their grids.”