Photo: Atle Harby
What makes hydropower so good compared to the other renewable sources such as solar and wind power is that it can be stored and used when needed. This makes it flexible. When environmental measures are introduced to protect nature from the negative effects of hydropower, this flexibility is reduced. The producer cannot, for example, stop all production to save water during periods of drought, because there is a requirement that they must maintain a minimum flow of water in the waterway below the power plant.
In HydroCen, the researchers have tried to find a way to measure this loss of flexibility in the hydropower system due to the introduction or change in environmental restrictions. This is to add this information to existing methods for measuring flexibility.
Use of fictitious storages
Together with Vattenfall R&D, the researchers have therefore tested a method called equivalent electrical storage (EEL). This represents a storage that describes the loss of flexibility in a hydropower system because of changes in the way one is allowed to operate the power system. The storage is described with a storage capacity (GWh) and power (MW). The results are based on data from selected case studies, where the stochastic optimization model ProdRisk is used to provide the data basis.
Using the analogy of a fictitious storage (for example, a battery), the method provides a visual approximation of the flexibility capacity of the hydropower system.