Is a troll about to disrupt the European energy system?

December 9, 2022
3-5 minutes

A cold blast, dubbed the Troll from Trondheim, is hitting the northern part of Europe this week, sending temperatures below 0°C and as a result putting a toll on the energy system.

Cold Arctic air has been descending over Norway, Sweden, and the UK in the last couple of days, pushed by a combination of high pressure over Greenland and low pressure over Scandinavia.

The cold snap is also moving over Germany, France and Belgium.

Temperatures are lower by up to 10°C compared to the ones usually observed at this time of the year. Frost and snow warnings have been issued.

The question now is how long it will last if persistent high pressures create a blocking event. Latest forecasts show it could until mid-December.

Warmer than usual weather in November is turning into a very cold December period.

Taken in isolation, such an event is not unusual in winter. What can get European governments and electricity system operators worried is the impact such a cold blast can have on an already strained energy system.

A weather event like that is leading to a surge in energy demand for heating whether it is produced from gas or electricity. It could also impact renewable energy production: solar power plants by a thicker cloud cover, wind farms by lower wind speed or potentially iced blades. In Germany or Denmark on December 7th, wind production was down to 30% of last year level.

Lastly, heavy snow or icing could lead to transmission lines breaking.

The European energy system is already affected by several factors this winter: gas supply from Russia has dropped, nuclear availability in France, Sweden and Finland is much lower than usual, thermal power plants have been retired, water reservoir are sometimes low following last summer droughts.

High levels of gas storage are in the short term mitigating part of these issues but electricity supply could start to struggle, a combination of several factors potentially leading to outages or even worst a blackout.

Electricity system operators outlook for the winter led to raising public awareness on the importance of energy efficiency. The various ways to reduce energy use should contribute to keep the system safe. But we are already seeing warnings being issued to avoid straining the system at peak hours.

Households, commerce and industries are facing further economic strains as the electricity and gas prices will increase further from already sharp levels.

Europe is relying on cooperation between countries and the interconnections between the national electricity systems. It will work as long as the cold spell is not too lengthy in time or geographically extended or combined with other availability issues.

To make things even worst, with most thermal power plants being mobilized at high levels, the carbon intensity of some countries is sky rocketing: 621 g of CO2 in Germany on December 7th and 860 g in Poland on the same day.

The Troll from Trondheim is the first significant test on the European energy system, however the biggest risks are foreseen in January and February 2023.

(Sources:, ENTSOE, Fraunhofer ISE;  picture Mark Konig / Unsplash)