Exploring the Potential for New Pumped Storage Power

Fortum has initiated a two-year feasibility study for new pumped storage power in Sweden. This involves thorough examination of the commercial, technological, environmental and regulatory conditions for new pumped storage in three areas in Sweden. Fortum's starting point is that any new pumped storage should contribute to a reliable power system, meet environmental criteria, and be economically viable.

The geographic focus of the feasibility study is in three areas: Lekstjärnen at Trängslet in Dalarna County, as well as Bastvålen and Höljessjön, both in Värmland County. These areas meet many of the criteria required for a pumped storage plant, such as sufficient head and closeness to a grid connection.

In Finland, Fortum’s associated company Kemijoki Oy is exploring pumped storage hydro power plants in northern Finland.

Objective

The objectives of the feasibility study are in line with Fortum’s strategy to provide reliable clean energy and drive de-carbonisation in industries in the Nordics, and to contribute to a successful energy transition which supports the competitiveness of the Nordic region going forward.

The volatility in the power market will increase as the share of weather-dependent renewables increases in the energy system. The role of flexible solutions, such as flexible pumped hydro storage, will be crucial in an expanding energy system to meet the increasing electricity demand, balance the energy system and help mitigate short-term changes in demand.

Implementation

During the feasibility study, Fortum will explore the many aspects and requirements to be in place for pumped storage power plants. Fortum will also investigate how the capacity of pumped storage plants can strengthen the Nordic energy independence and support a secure energy supply. The feasibility study will continue for about 2 years.

How a pumped storage power plant work

A pumped storage power plant has two reservoirs, located at different heights and with a power station in between. The power station consists of a pumped turbine, a motor generator, a transformer and electrical and control equipment. The reservoirs are connected to the machine station by water pipes/tunnels. When demand for electricity is low, water can be pumped through the power plant up from the lower reservoir to the upper one, to be stored there. When pumping takes place, the power plant consumes electricity.

Fortum's existing pumped storage power plants

Eggsjön Power Plant

Location: Torsby Municipality

Commissioned: 1957

Capacity: Head of 18 m, 0.6 MW, generates approximately 0.5 GWh/year

Letten Power Plant

Location: Torsby Municipality

Commissioned: 1956

Capacity: Head of 191 m, 36 MW, generates approximately 65 GWh/year

The Letten power plant is designed for seasonal storage and is operated more frequently today. It has separate pumps and turbines and is manually operated to switch between pumping and power generation.

Kymmen Power Plant

Location: Norsälven, Sunne Municipality

Commissioned: 1986

Capacity: Head of 88 m, pumping capacity of 53 MW, generates approximately 47 GWh/year

Description: The Kymmen power plant consists of a reservoir, Lake Kymmen, and a pumped storage power plant in the mountain. The power plant is highly flexible and can respond to price signals, offering flexibility over various time periods, from seconds to days.