Throughout the summer, there was less rainfall than normal in large parts of southern Norway. It followed a winter with less snow than normal, at least around Møsvatn in Telemark. That’s what Jostein Eggerud in East Telemarken’s utility owners’ association says. New figures from NVE show that Norwegian water reservoirs in southern parts of Southern Norway and Eastern Norway have a degree of filling of 50.6 and 68.8 per cent respectively. Level of filling in the Norwegian water reservoir Eastland 68.8 per cent, a change of 0.3 percentage points from last week. Southern Norway 50.6 per cent, a change of 0.2 percentage points from last week. Central Norway 82.5 per cent, a change of -0.2 percentage points from last week. Northern Norway 88.5 per cent, a change of -0.9 percentage points from last week. Measured on 25 September. Source: NVE – It has been between 60 and 80 per cent of the normal amount of snow in the last two years. When we also get a heavy period with little rainfall then, it becomes strained. In the last few days, 70 mm of rain has fallen in Tinnsjøen. – It contributes to a long-awaited increase in the reservoir and an important supply after six months of modest rainfall, says Eggerud. Much of the rainfall goes to replenish groundwater and ground water, so the more intense the rainfall, the more reaches the reservoirs, he explains. Last year, 160 millimeters of rain fell in a short time in autumn. If it falls straight into Møsvatn, it means a replenishment of almost 12.5 billion liters of water, according to calculations made by news. In addition, water comes from the catchment area to Møsvatn, which is 1,500 square kilometres. – But there must be a marked increase in rainfall over time to approach a normal situation. We want a lot of rain and snow, says Eggerud. Must rain significantly more than usual It doesn’t help that it only rains a lot in one magazine or one area. All the reservoirs in South-West Norway must have a lot of rainfall. The same is said by Grunde Johnsen in Otteraaens Brugseierforening, which is responsible for the regulations in the Otravassdraget in Agder. At the top of the watercourse is Vatnedalsvatnet, also one of the country’s largest power reservoirs. – If there is 20-30 per cent more precipitation than normal before the precipitation arrives as snow, we consider that the situation is approaching normal for us, says Johnsen. In the upper part of Otra, 25 per cent less power has been produced this year than the average from the last decade, Johnsen says. LOW WATER LEVEL: The Vatnedals dam in Bykle in Agder has, as you can see from the divide in the terrain, a significantly lower water level than normal. Vatnedalsvatn has a regulatory height of 140 metres. The picture was taken on 30 August. Photo: Kristine Stoveland Solvang Does rainfall help the price? The Norwegian Directorate of Water Resources and Energy (NVE) has no concrete figures on how much rainfall is required to fill up the water reservoirs in this area. – For the amount of rainfall to affect electricity prices, it must rain more than normal to make up for the dry summer, says Ann Myhrer Østenby, section manager at NVE. DRY IN THE SOUTH: Large areas in southern Norway have been extremely dry in the summer months this year, according to the overview from the Meteorological Institute, which was published on 2 September. Photo: Meteorological Institute In addition, there are other factors that determine the price passed on to consumers. – The war in Ukraine and the gas supply from Russia to Europe will be very important factors for power prices going forward, in addition to rainfall and temperature, says spokesperson Lars Magnus Günther in Statkraft. – Won’t reach normal levels this autumn Blåsjø on the border between Rogaland and Agder produces 7.7 terawatt-hours a year, and is therefore Norway’s largest power storage in terms of energy quantity. Here, the fill rate has been down to around 20 per cent at its lowest point earlier this year. – Now the degree of filling is between 40 and 50 per cent, but normally at this time of year it is in excess of 70 per cent, says Günther in Statkraft. They have operational responsibility for Blåsjø. This enormous perennial reservoir needs three years of normal rainfall to fill from zero to 100 percent. – In order to save water for the winter, Statkraft has almost no power production from Blåsjø, says Günther. This means that the magazine will rise somewhat throughout the autumn. – But we will not reach normal levels this autumn, given normal inflow. More rainy days and more intense There may still be hope in autumn. – Between 300 and 600 millimeters of rainfall usually falls in our area in three months in the autumn, says Asgeir Sorteberg. He is professor of meteorology at the University of Bergen and the Bjerknes Center. NEED RAIN: It is not certain that everyone appreciates it as much, but it will take a lot of rain this autumn if it is to affect electricity prices, says NVE. Photo: ISMAIL BURAK AKKAN / news That it rains 20 to 30 per cent above normal in the autumn has not been unusual in the past decades, Sorteberg says. On 1 January 2021, the Norwegian Meteorological Institute stopped using the period 1961–1990 as a starting point when talking about normal weather. Now it is 1991–2020. – It will be a lot more difficult to get 20-30 per cent above the new normal, since it is higher than the old one, says Sorteberg. When rain turns to snow, you don’t get to make use of it until it melts in the spring, he points out. In July this year, between 50 and 75 per cent of the rainfall that usually falls in the areas where the water reservoirs are located, says Sorteberg. The intensity of the rainfall has increased and it rains between 14 and 21 days more each year than 100 years ago. – In general, the thunderstorms have been too far east this summer, says meteorologist Marit Berger at the Meteorological Institute. Much of the precipitation has fallen around the Oslofjord and in Sweden. At the same time, it has rained well in Western Norway, but it has not reached far enough into the country. – This does not mean that it has not rained well in some places in the mountains, but here there is a longer distance between the measuring stations.
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Shrinking reservoirs in Telemark – need a soaking wet autumn – news Vestfold and Telemark – Local news, TV and radio
