Optimal operation of hydropower systems with environmental constraints on reservoir management

Hydropower is a low-carbon energy technology with a unique capability to provide flexibility and long-term energy storage, thus being a key contributor to cost-effective and reliable decarbonisation of power systems. To ensure sustainable operation, environmental regulations are normally imposed on the plants. Some of these regulations can be difficult to model in existing scheduling tools based on optimisation because of their non-convex and logical characteristics. This study contributes to the existing literature by assessing the operational impacts of two types of complex environmental reservoir constraints, with the aim to identify the operational implications as well as the economic impacts of including these constraints in medium-term hydropower scheduling. The results show that optimal reservoir management may change considerably due to these types of constraints. An important finding is that improved planning can reduce the economic loss associated with the environmental regulation, nevertheless, it is shown that the improvements depend on the power price and the characteristics of the hydropower system. • Improved modelling of environmental constraints in a hydropower scheduling model. • Assesses operational impacts of environmental reservoir constraints in the scheduling. • Assesses economic impacts of environmental reservoir constraints in the scheduling. • Discussing the sensitivity of these impacts to changes in market prices and capacity.