New research casts doubt on the view that pumped hydro power could allow Norway to act as battery pack for other parts of Europe.

Dr. Björn Peters, a German energy investor turned researcher, says that even though Norway’s hydro capacity is “huge,” most of it is in fact needed to power Norway.

“Theoretically, Norwegian electricity storage would be sufficient to compensate for the fluctuations insolarand wind energy in Germany, even if Germany was supplied solely by sun and wind energy,” he said. 

“However, since 2002 an average of about 44 terawatt-hours had to be stored between the summer and winter in Norway. The lowest and highest filling levels of the reservoir lakes were [between] about 15 terawatt-hours and slightly over 77 terawatt-hours.”

This means nearly all the country’s 82 terawatt-hours of storage was used by Norwegians, Peters said. 

Norway’s 5 million citizens use about three times as much electricity per head as their counterparts in Germany, Peters noted, because Norwegian heating systems more often tend to be electric-powered and the winters in the Nordic country are longer. 

The load on the electricity system in Norway is growing because of the country’s world-leading vehicle electrification program, which could see the nation phasing out internal combustion engine cars altogether by 2025.

Today, electricity consumption in Norway amounts to 140 terawatt-hours a year, or about one-fifth that of Germany, Peters said.

Peters said there are several other reasons why the country is poorly suited to providing storage for nearby European countries such as Germany.

One is that Germany’s need for energy is likely to increase at the same time as Norway’s -- in midwinter, when electricity use is highest and solar power’s contribution lowest.

Norway also would need a way of replenishing its lakes on demand. Currently, the country's reservoirs get filled by spring meltwater and summer rain. “Pumped storage power plants are rarely built,” said Peters. 

There is significant local opposition to the idea of flooding more land to create pumped hydro reservoirs.

And the number of extra reservoirs needed is not trivial. Peters estimates Norway would have to install more than 100 terawatt-hours of pumped hydro storage.

A storage capacity of this magnitude “would only be conceivable using seawater,” he said. "But this would lead to a salinization of the reservoirs and thus a considerable negative environmental impact.”

Even if Norway were to undertake a massive pumped hydro build-out program, such as that suggested by Kaspar Vereide of the Norwegian University of Science and Technology in 2015, there are not enough grid connectors to get the electricity to and from Germany and beyond.

The transmission capacity between Norway and Germany would need to go up from the two 1.4-gigawatt links at present, said Peters, to a total of around 120 gigawatts. Plus, additional transmission infrastructure would have to be built across Norway.

“Major transformation of the entire power system is required if Norway were to act as a ‘battery for Europe,'” said Peters, who is skeptical of whether sufficient European storage can be built anywhere to allow for a full transition to intermittent renewable generation.

“The reservoirs are needed in Norway and are not available for balancing additional fluctuating power generation capacities abroad,” he said.

Other European energy experts agreed with this assessment.

Hugh Sharman, principal at the Danish consultancy Incoteco, said: “The main task of the [Norwegian] transmission system operator Statnett is to serve Norway's demand, so there will definitely be limits to its ability to balance the networks of its much larger neighbors.” 

Furthermore, Peters’ calculations do not take into account whether Norwegian politicians would be supportive of a plan to become Europe's battery. 

Anne Therese Gullberg, a senior researcher at the Center for International Climate Research, analyzed that likelihood in 2013. 

She concluded: “Decisions about new interconnectors are made on an individual basis, [and] there is little reason to believe that this status quo policy will change.”