The PhDs Gro, Igor and Johannes are studying turbines at NTNU's Hydropower Lab.
The enormous forces of water rushing through the tunnel and into Norwegian hydropower plants are almost 100 percent utilized to produce power. Only 4-6 percent of the energy in the water is wasted when it passes through a Francis turbine. It has worked perfectly for a hundred years, but climate change is leading to both more unstable weather conditions and cuts in fossil energy sources. This means that hydropower must now operate in a new way.
Conventional water turbines are designed to operate continuously at a fixed speed to produce an expected amount of electricity for the grid. When today's hydropower is to function more like a green battery that is switched on and off depending on how much solar and wind energy is produced, the turbine faces a major challenge.
It performs less well when exposed to water volumes greater and less than it was designed for. This leads both to energy/power production becoming less efficient and to increased wear and tear on the turbine parts. This wear and tear leads to expensive repairs and can lead to reduced confidence in the power plant, which then cannot deliver the services needed when they are needed. One solution to this is to provide turbines and generators that can operate just as well at variable speeds as current technology does at constant speeds.