TLDR Europe is relying too heavily on Norway for dispatachable hydro, pushing up power prices for domestic electricity users in Norway due to their exposure to Europe wide electricity prices. Potential short term solution is to increase electricity prices for exported power to reduce power prices domestically, while the long term solution is more battery storage across all of Europe. Broadly speaking, Europe has not prioritized energy storage economically (for both energy arbitrage and grid services), leading to teething pains as renewables carry more of the generation burden (Spain's recent national blackout caused by lack of non thermal grid services and battery storage available, for example).

Their argumentation is pretty naive. If they would truely like to fix up the situation, they could simply put a tax on the exported electricity. Depending on the height of the tax, exports would be adjusted accordingly. Maybe, a non linear taxation scheme would be needed to allow exports in normal operation states and prevent exports in high price situations.