The potential of pumped storage

What is pumped storage?

Pumped storage power is an energy storage technology that plays a crucial role in balancing the electricity grid by storing excess energy from renewable sources and releasing it when needed. In Sweden, hydropower is an important part of the energy mix, but the use of pumped storage power is still limited.

A typical pumped storage power plant consists of two water reservoirs, a pump turbine, a motor generator, a transformer and associated electrical and control equipment. When there is a surplus of electricity production from wind and solar power, the energy is used to pump water from the lower reservoir to the higher one. When the demand for electricity is greater than the production, the water in the higher reservoir can be released back down through the turbine, generating electricity that is fed into the grid.

Martin explains that a pumped storage power plant has many similarities to a conventional power plant, but there are also important differences. One of the biggest differences is that a pumped storage power plant needs to be able to both pump up and turbine (drop down) water. Usually this takes place in the same waterway with a generator consisting of a reversible pump turbine and a motor generator. It is also possible to build separate waterways to pump and turbine water, but this is more rare.

Another important difference is that a pumped storage power plant is not dependent on a continuous influx of water into a watercourse in the same way as a traditional hydropower plant is. A pumped storage power plant can reuse the same water over and over again during repeated pumping and turbining, which means that it can generate energy in a sustainable and efficient way without consuming large amounts of water resources.

Challenges

Pumped storage power has the potential to create long-term economic gains and increase energy security in Sweden, but it also faces several challenges. The initial investment costs for a new pumped storage power plant are high, which may constitute a financial barrier to development. In addition, the establishment of a new power plant, with associated water reservoirs and power lines, affects the local ecosystems and can have significant environmental impacts. To ensure that projects are carried out responsibly and with consideration for the environment, there are strict environmental regulations and careful permit processes to adhere to.

Martin believes that there are several factors to consider in order to establish new pumped storage power plants. A basic prerequisite is to identify a potential site with a sufficient height difference between the lower and upper water reservoirs. The distance between the reservoirs must be manageable, and they must have sufficient capacity for large-scale energy storage.

He points out that there also needs to be sufficient capacity in the electricity grid to connect the power plant. When a promising site is assessed as economically viable, it is important to carefully examine how the project may affect people, natural and cultural environments. This work gives us an opportunity to propose measures to minimize any impact and make the project as sustainable as possible," says Martin.

After these aspects have been investigated, the permit process can be initiated. Martin also mentions that there is a growing public awareness of the need for energy storage to support an increased share of renewable and non-renewable energy sources in the electricity grid. With the right investments and technological advances, pumped storage power can become a key component of Sweden's future energy system.

Future of pumped storage

Pumped storage power offers a promising solution for balancing the electricity grid and supporting the transition to more renewable energy. By addressing the current challenges, Sweden can use this technology to create a more sustainable and stable energy system.

Increasing the capacity for large-scale energy storage from surplus production is crucial for the continued expansion of wind and solar power, while ensuring the stability of the electricity grid," says Martin. He points out that pumped storage power offers an efficient and sustainable solution for large-scale energy storage and can also provide valuable support services for frequency regulation in the electricity grid. At the moment, there are only a few pumped storage power plants in operation in Sweden, which means that there is great potential for establishing new pumped storage power solutions.

AFRY's expertise in pumped storage solutions

AFRY is a leading player in pumped storage power, both in Sweden and globally. We offer our expertise at every stage of the projects and work closely with our clients to ensure that every phase, from initial planning and technical investigations to implementation and operation, is carried out with the highest quality and efficiency.

One of the projects we are working on right now is Juktan's pumped storage power plant," says Martin. Our role is to carry out technical investigations to optimise the performance and safety of the plant. He explains that the results of the investigations will form part of the basis needed to make an investment decision. It's a really interesting and fun job where we get to show our technical expertise and ability to find innovative solutions in the best way," says Martin.

Pumped storage power is emerging as a key component in the pursuit of a more sustainable energy system. With the increasing share of renewable energy sources, it is becoming increasingly important to develop efficient storage solutions to ensure the stability of the electricity grid, and by meeting the current challenges, pumped storage power can play a crucial role in providing a reliable and fossil-free energy supply for future generations.