Technical Review of Existing Norwegian Pumped Storage Plants

Abstract

This paper presents a technical review of the existing pumped storage plants in Norway. The power system is changing towards integrating more and more renewable energy, especially from variable renewable energy sources, leading to new challenges for the security of supply, power, frequency, and voltage regulation. Thus, energy storage options are a highly researched topic in the current situation. Even though there are many energy storage technologies, most are optimal for short term grid balancing, and few are capable of providing long term (weekly or seasonal) storage. One exception is pumped storage, a mature technology capable of delivering both short term and long term energy storage. In this paper, the ten existing pumped storage plants in Norway are presented, several of which are capable of seasonal energy storage. The Norwegian knowledge and experience with pumped storage plants technology is provided as a basis for future research within the field. The review provides information about energy production and storage capabilities, construction costs, specific costs per kW and stored kWh, electromechanical installation, technical specifications, and operational experience with focus on the design of the tunnel system layout. The data presented in this review are unique and previously unpublished. A discussion and conclusions regarding the current situation, trends, and future outlook for pumped storage plants in Norway within the European power market are provided.

Optimal Utilisation of Grid Capacity for Connection of New Renewable Power Plants in Norway

“…The round-trip efficiencies of the Norwegian pumped storage facilities are found in [36] to be in the range 65% − 80%, which is consistent with the efficiencies mentioned in [34] and [33]. Pitorac et al [36] also highlight that the reaction time of the pumped storage facilities in Norway is high, due to being designed for seasonal storage. However, the possibility to upgrade the starting mechanisms and consequently reducing the reaction time is concluded to be present.…”

“…Nevertheless, the fixed-speed turbine is more common, as it is cheaper than the variable-speed turbine [34, p.3]. Even so, it is expected that the variable-speed turbine will be used more frequently, in line with the anticipated increase of VRES in the power system [34, p.3 Furthermore, the technical part of the review in [36] shows that the Norwegian pumped storage facilities are mostly constructed for seasonal storage, having an upper reservoir that is considerably larger than the lower reservoir in the system. This comes from the facilities being built for pumping inflow to the upper reservoir during flood season, and not for pumping to the lower reservoir.…”

“…On average, over 90 days of operation are needed to empty or fill the upper reservoirs, compared to just 22 days to fill the lower reservoirs [36, p.5]. The round-trip efficiencies of the Norwegian pumped storage facilities are found in [36] to be in the range 65% − 80%, which is consistent with the efficiencies mentioned in [34] and [33]. Pitorac et al [36] also highlight that the reaction time of the pumped storage facilities in Norway is high, due to being designed for seasonal storage.…”

Isothermal Deep Ocean Compressed Air Energy Storage: An Affordable Solution for Seasonal Energy Storage

“…Furthermore, the high demand for batteries in electric vehicles and grids raises questions about sustainability and resource availability [10,11]. Mountainous regions can provide seasonal energy storage with mountain gravity energy storage [12] and PHS [13,14]. In locations without mountains or water, converting electricity to synthetic fuels such as hydrogen is seen as the main solution to seasonal energy storage [4]; however, this method Energies 2023, 16, 3118 2 of 18 has low efficiency and a high capital cost [15].…”

The Strategy of Considering the Participation of Doubly-Fed Pumped-Storage Units in Power Grid Frequency Regulation

“…As a mature traditional energy storage method, the pumped storage unit (PSU) occupies an important position in the power system with its great peak shaving ability [1][2][3]. Among them, the doubly-fed pumped storage units overcome the shortcomings of the traditional pumped storage units with non-adjustable rotational speed, and play an important role in improving the operational stability of the power grid and increasing the energy utilization rate, thus becoming one of the mainstreams of new units in pumped storage power plants nowadays.…”