Norway’s Reservoir Lakes — Batteries for Europe?

Norway’s energy storage facilities are mentioned in many German energy discussions as possible power storage for Germany, in order to buffer the fluctuating power input from sun and wind. In 2011, the title „Norway as a battery of Europe“ even appeared in the German weekly newspaper ‚Die ZEIT‘. Obviously, this looks like a great economic idea for an era when Norway’s oil and gas fields have dried up.  In the future, Norway could export electric power and demand-supply flexibility to balance weather-induced production volatility instead of oil and gas.  Let’s see whether this is really an option.

First, we need to take a closer look at Norway’s storage facilities and its electricity generation system. Norway’s supply of electricity is generated almost exclusively by hydroelectric power plants. Since it does not rain in the winter and the rivers freeze, huge reservoirs are needed to collect the melt water in the spring and the rain in the summer in order to provide sufficient electricity in the winter. The storage facilities only collect natural rainwater runoff; pumped storage power plants were rarely built. Electricity pipelines from Norway, especially to Sweden, Denmark and, more recently, the Netherlands compensate, if the capacity of the power plants in either of these countries is insufficient. So far, however, there is no direct connection from Norway to the electricity network in Germany, but for this purpose the Nord.Link and NorGer projects should be completed in the coming years.

The roughly five million Norwegians consume about three times as much electricity per capita as the Germans. This is mainly due to the fact that Norwegians heat mainly with electricity, which costs about half as much as the German’s, and their winters are long. Due to a substantial tax allowance of sometimes more than one hundred thousand Euros per car, there are already many electric cars on the roads. Altogether the Norwegians consume about 140 billion kilowatt hours or terawatt hours (TWh) annually and thus a good fifth of the whole of Germany.

 

Norwegian reservoir lakes…

The reservoir lakes are huge with over 82 TWh of maximum storage capacity (see figure below). In comparison, all German pumped-storage power plants have below 0.05 TWh of storage capacity. Theoretically, the Norwegian electricity storage would be sufficient to compensate for the fluctuations in solar and wind energy in Germany, even if Germany was supplied solely by sun and wind energy. However, since 2002 an average of about 44 TWh had to be stored between the summer and winter in Norway, sometimes much more. The lowest and highest filling levels of the reservoir lakes were, when calculated in energy, about 15 TWh and slightly over 77 TWh, hence nearly all of the 82 TWh maximum storage capacity was actually used. The reservoirs are therefore needed in Norway and are not available for balancing additional fluctuating power generation capacities abroad.

Stromspeicher_Norwegen_en

 

…vs. technical requirements in Europe

In addition, there are several factors that make the Norwegian reservoirs unsuitable for German or even European needs today.  Major transformation of the entire power system would be required, if Norway would actually have to act as a ‘battery for Europe’.

  • The power transmission network within Norway is insufficiently developed. The capacities within the country are just sufficient for their own electricity supply.  Major buildouts of transmission lines by a factor of 50 would be necessary in order to connect to Europe.
  • Instead of the two currently constructed power lines between Norway and Germany, which will have a transmission capacity of approximately 1.4 GW each, the transmission capacity to continental Europe would have to be increased to about 120 GW.
  • The production capacity of Norwegian storage plants in MW is insufficient for a usage as a European storage and would have to be multiplied by increasing the possible flow rate by installing larger turbines.
  • Instead of simple storage power plants, the function as a ‘battery of Europe’ would also require pumped-storage power plants to absorb energy surpluses from the sun and wind (so-called negative power). These are still practically non-existent in Norway. To install the relevant negative load in Norway, pumped hydro power stations in the order of magnitude of more than 100 TWh would be required.  Such large pumped hydropower plants would only be conceivable using seawater, but this would lead to a salinization of the reservoirs and thus to a considerable negative environmental impact.

An integration of Norwegian reservoirs into the German and European electricity network would therefore require large scale modifications and sizeable investments. Furthermore, the construction of new reservoirs in Norway has failed, because of resistance from the local population. Entire valleys would have to be converted into lakes, rendering them impassable for humans and reindeer herds. And lastly, the Norwegian reservoirs provide power to the Norwegians mainly in the winter, exactly the same time, when the power supply in continental Europe is low and additional power sources are required, expecially during times when wind and solar energy cannot be harvested due to unfavorable weather conditions.

 

All in all, using Scandinavia to buffer continental Europe’s fluctuating wind and solar power – an idea that seems compelling at first glance – does not look so convincing when really thought through.

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