-CHANGING-RESERVOIR-NORMALS

CHANGING RESERVOIR NORMALS

In the process of making new hydrological normals for elspot areas instead of regions in Norway and Sweden, we have done another controlled simulation with the EMPS model and simulated new reservoir normals. We have not updated the inflow statistics used in the simulation, the only change lies in the hydro producer’s production and the reservoir normal being a result of this. Our reservoir normal has a slightly different path now, with some changes in the yearly profile. Most noticeable is the change in Swedish reservoir normal, where the average filling during the summer has increased. In addition, both countries show higher reservoir levels at the start of the year. The new reservoir normal for Sweden is quite similar to the reservoir normal used by Svensk Energi during the summer. And the higher average filling during summer, match the oversupply that comes into the NP market through the elcert scheme, with more renewable generation, and a larger variation band. Due to this, the average filling has increased somewhat, as the regulated reservoirs are the ones that benefit the most from saving water and producing at a different time, even with an increased risk of spilt water.

The new normals have been implemented in our models as of today. The immediate effect is an increase in the hydrological balance of a minor +0.5 TWh on week 5, all other things kept the same. For week 52 the change is +1.1 TWh, with the reservoir in Norway decreasing -1.2 TWh, the reservoir in Sweden decreasing -1 TWh, while the Norwegian snow increased 2.3 TWh and the Swedish snow increased 1.1 TWh. The change in hydrological balance comes solely from a change in the reservoir normal used for comparison, where the normal reservoir filling around week 1 is higher both in Norway and in Sweden in the new normal. So the reservoir balance decrease in both countries when comparing with the new normal.