Abstract
Significant investments in renewable energy sources are being made globally [1]. Integrating wind and solar power, which are intermittent energy sources, presents a substantial challenge for power systems. The mismatch between energy generation and demand fluctuates [2]. Addressing this challenge requires developing flexibility within the system to effectively manage these unregulated energy sources [3]. Pumped Hydro Energy Storage (PHES) is a regulative renewable energy source which offers long- and short-term energy storage [2]. As an environmentally sustainable resource, hydropower enhances flexibility and storage capacity within the energy grid. These attributes are crucial for improving grid stability, supporting the integration of intermittent renewable sources and facilitating load balancing [4]. This thesis explores the implementation of PHES in the eastern part of the Røldal- Suldal power system (RSK). Furthermore, it examines the effects of different pump sizes on the operational dynamics of the system. The program used for simulating the hydropower system is ProdRisk, which employs a combination of Stochastic Dual Dynamic Programming (SDDP) and Stochastic Dynamic Programming (SDP). These methods are ideal for optimizing hydropower scheduling [5]. The simulations of the RSK system were run on the ProdRisk portal using the code language python. The simulations examined pump sizes of 10 MW, 20 MW, 30 MW, and 40 MW over a 30-year period, utilizing simulated electricity prices from the EMPS model. In summary, implementing a pump in the eastern part of RSK is projected to increase income from electricity sales compared to a system without a pump. A plant equipped with a bigger pump has a longer operation time, both for the turbine and pump. This is particularly notable during years of low inflow. While a turbine with a larger pump may have lower efficiency, the pump empowers the turbine to generate more electricity when the demand is high. The annual mean production is increasing from 962.9 GWh in the baseline simulation (0 MW) to 1000 GWh for the 40 MW pump simulation. However, annual net production declines with larger pumps, dropping from 962.9 GWh in the baseline simulation to 955 GWh for the 40 MW pump simulation. Moreover, revenue from electricity sales increases by 2.56% for the largest pump of 40 MW compared to a baseline simulation. Overall, this thesis demonstrates the application of ProdRisk and the beneficial im- pacts of PHES implementation. Utilizing PHES could be crucial in enhancing the stability and flexibility of future power systems, while also helping to ensure that global temperatures remain below 1.5oC.