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Musings about the environment and all it touches, from education to city planning

Pumped energy storage (a visit to Geesthacht)

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IMG_8091Often we’re told that renewable energy is not practical without a method to store electricity; after all, it’s not always windy or sunny. I decided to go see an energy storage set-up for myself, in Geesthacht, a small town on the Elbe just east of Hamburg.

Northern Germany is mostly flat, but nevertheless there are small rises. The Elbe has carved some cliffs in these rises. One of these, above Geesthacht, has been used for pumped storage. There, a small reservoir has been dug above the river. It gets pumped full of water from the Elbe below when power is cheap (at night, for instance). When electricity is in high demand (typically, late afternoon for domestic power), water is let out through turbines, generating electricity.

You and I may pay the amount per kilowatt-hour regardless of when we turn on the lights, but it costs much more money to produce electricity when there is a high demand than, say, in the middle of the night. During low demand times, companies rely on so-called baseload power (what coal, nuclear, or large hydro power plants produce day in, day out). But at peak times, special power plants, called “peakers”, are brought on-line to add extra power. In BC, the gas-powered Burrard Thermal plant in Port Moody is an example of a peaker plant; the 900 MW facility is on only about one percent of the time.

An alternative to peaker plants, which produce greenhouse gases, is hydraulic storage, like the one used in Geesthacht. This is just one of fifteen such facilities in Germany (most are in the hillier south). The Swedish company Vatenfall, the owner of the facility, has also built a windmill and a solar farm on site; these two add-ons are also used to pump water uphill.

When I visited, the site was wreathed in mist. The windmill was silently turning, invisible except when right under it. The solar collectors were idle. But the impression of raw power was obvious: the three pipes, each nearly four meters in diameter, were churning the Elbe waters down below, three invisible rivers cascading downhill – and the plant wasn’t even at full power.

the windmill in the mist

The windmill in the mist

Using pumped storage instead of a peaker plant prevents the emission of greenhouse gases, so it has a positive impact on the environment and the climate. It’s not problem free, mind you: pumping large amounts of water in and out of a river can be disastrous for fish entrained in the pipes. The environmental group NABU sued Vatenfall recently for this very reason. And the German government considers that pumping water out of the Elbe is like any other extractive water use and charges for the permit. As a result, the Geesthacht facility is not used to its full potential. And the reservoir is small: it is useful for a daily cycle of energy demand, but it is of limited help for longer storage periods.

What is most surprising, at least to me, is the age of the facility. Was it built in the 90’s, in response to climate change? No. In the 70’s then, during the energy crisis? Neither. It dates from 1958. It was built before any of these concerns rose to the surface – just because it was considered good engineering at the time, when Germany’s (re)industrialization was leaping ahead.

What does that mean for us in BC? We have mountains, and we have water. Hydropower can be fairly finely tuned, if necessary, so (except for Burrard Thermal) we have little need for peaker plants. But water storage has much more potential than this: we could manage our current hydro plants in tandem with wind power, which we are nowhere near developing to capacity in the province. The Peace Valley, by itself, has the potential to generate much more electricity that the proposed Site C plant. And we already have an enormous storage potential for those days with little wind…

Air photo of the site, from the Geesthacht tourism office

Air photo of the site, from the Geesthacht tourism office

By the numbers:
Rated power: 120 MW (less than 3% of Germany’s pumped storage capacity)
Reservoir size: 3.6 million cubic meters capacity, 93 meters elevation, 80 meters head
Discharge: 66 m3/s through three pipes with internal diameter of 3.8 meter
Wind turbine: 500 kW, 1100 MWh/a
Solar PV farm: 60 kW, 573 m2, 50 MWh/a


Written by enviropaul

November 16, 2015 at 3:10 am

One Response

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  1. […] As it is, the weir backs up the waters about 30 kilometers upstream. But the original higher design would have raised the level of the Elbe all the way into what used to be East Germany. In the middle of cold war tensions, the East Germans protests were heeded. Nevertheless, the more modest level agreed upon was enough for year-round ship traffic in the Elbe-Lübeck canal, as well as for the intake of the Geesthacht pumped energy storage plant. […]

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