Case study

Energy storage system solutions for Kemijoki

This research was conducted for Kemijoki, investigating solutions within energy storage systems (ESS).

A case study for Catapult
Research challenge for edtech

The challenge

Wanting to improve on hydropower efficiency through the use of ESS

The process

An overview of the 8 week research process

The outcome

The delivery of the ESS solutions and the impact of the research

The challenge

To improve the hydropower efficiency through ESS technology

The two biggest needs for Kemijoki were:

Decreasing wear-and-tear

Balancing the energy consumption

Fast frequency

Improving fast frequency containment reserve capabilities

When the share of variable production increases and the share of fossil fuels decreases, it becomes more difficult to manage the balance of the electricity system as the natural tolerance to disturbances weakens.

Consequently, the technical performance requirements of frequency-controlled reserves must be updated. The task of frequency-controlled reserves is to respond to changes in electricity production and demand at the second-by-second level, which must always be in balance.

A case study for Catapult

The process

Week 1

The definition of the interest and development area for research.

Week 2
Kickoff workshop

Interview-based workshop with the client team in order to define the research focus area. The research team builds & verifies the research description & criteria.

Weeks 3-7
Research implementation

The Catapult research team gathers, analyses & validates data based on the set criteria. Midway check-ups for updates and clarifications are set to steer the research forward.

Week 8
Research delivery

Presentation of the comprehensive research results.

The outcome

business tech and Innovation market research

Market overview

Investment landscape and general information about the market

Longlist of solution companies in tech & innovation research


A longlist of different players in the market


A shortlist of the most feasible solutions in the market

Case profiles

13 detailed case profiles from different industry verticals

A few highlighted verticals


Energy storage systems based on supercapacitors


Energy storage systems based on flywheels


Other energy storage systems

Kemijoki has been investigating the joint use of hydropower and batteries since 2017. In 2020 we had a great honour to step into this journey to help them map out and gain a deeper understanding on various energy storage technology verticals.


“Thorough and out-of-the-box assessment.”


The world of electricity is changing, driven by climate and energy policy as well as geopolitics. All changes in the electricity market emphasise the importance of flexible, renewable and domestic electricity production, well packed with the storage system technology.  

Today, hydropower is superior in generating frequency-controlled reserves, and by combining the strengths of two different technologies, the whole is greater than the sum of its parts. The current focus is on improvements of the hydropower plant efficiency by using supercapacitors on short-time and high-power output storages.

A case study for Catapult

“That’s why I feel that the work with hydropower is meaningful: we enable the electrification of society, secure the transition towards a carbon-neutral electricity system, and offer solutions for curbing climate change and ending harmful energy dependencies.”

Sakke Rantala
COO at Kemijoki


After further consideration, Kemijoki decided to go with a supercapacitor as the new solution for electricity storage technology. Supercapacitors were chosen as the most optimal solution as they have the advantage in:

Charging capability

In a supercapacitor, energy is stored in the electric field and it can withstand more than a million charges, i.e. a 100 times more than an average battery.

Discharging capability

The energy volume of the supercapacitor is small, which in practice means that it takes less than a minute to fully discharge. Especially, in a real situation, the portion reserved for one swing is only seconds, so the interplay of hydropower and electricity storage must be seamless.

The supercapacitor solution is now being piloted as storing electricity for a hydropower plant. In addition, the pilot project will investigate the benefits of reducing the wear and tear of the machinery. The project is expected to scale up after validating the results of the first pilot which is is estimated to first launch in spring 2023.

By combining the strengths of hydropower and supercapacitors, Kemijoki can improve the performance of the power plant and participate in the reserve market even more strongly. We’re so thrilled to be a part of this journey on building a more carbon-neutral electricity system and sustainable energy consumption.

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