Unique underground cable line installed in Estonia for the largest battery park in Continental Europe

Baltic Storage Platform reached a noteworthy milestone at Kiisa in the course of the construction of the largest battery park in Continental Europe – for the first time in Estonia, a unique underground cable line operating at 330 kV voltage was installed, connecting the battery park with the connection point of the Estonian transmission network.

Baltic Storage Platform, a joint venture between the Estonian energy company Evecon, the French solar energy producer Corsica Sole and Mirova, an asset manager dedicated to sustainable finance, aims at building two battery storage parks in Harju County with a total power output of 200 MW and a total production capacity of 400 MWh. The first Kiisa project should be commissioned by the end of 2025 and should be followed by the second park in 2026. The battery parks will play a key role in the synchronisation of the Baltic countries with the European power grid.

“The construction of Kiisa battery park, with its cornerstone laid in the beginning of October, has advanced according to schedule. Construction on the substation building is steadily progressing, the foundations of the equipment have been laid and the foundations of the two 330 kV power transformers have been cast,” said Risto Virveste, Project Manager of Evecon. “However, the most significant detail is that recently, Connecto Eesti installed the first 330 kV alternating current underground cable line in Estonia. Cables with an operating voltage like that have never been installed before in Estonia. Usually, 330 kV overhead transmission lines are used for such solutions.”

The cable was manufactured in the Finnish Prysmian plant – a first for Estonia. It extends to 500 metres in length and has a notable diameter of 12.5 cm, said Risto Virveste. The cable was installed between the substation of the battery park and Elering’s 330 kV substation, which is where the connection point of the battery park with the Estonian transmission network is located.

“This cable is special due to its relatively high price. But in the current case, it was a reasonable solution, as there would have been crossings with several other 330 kV overhead transmission lines between Elering’s Kiisa substation and the battery park, which would in turn render the construction work difficult and expensive, as very high towers would need to be constructed, or the 330 kV overhead transmission lines of Elering would need to be reconstructed,” Virveste explained. The special nature of the cable and the voltage class are characterised by the fact that end insulators with a total length of 5 metres need to be installed at the ends of the cable.

“The installation work of the cable proceeded as planned and thanks to excellent preparation, we completed the installation of the cable in just three days. This is a great example of the level of professionalism and technical capacity of our team. Projects like these show how innovation and professional work combined help the Estonian energy system advance with great strides. The installation of the end joints in the spring will be the next stage,” said Valmar Raigo, Project Manager of Connecto Eesti.

Watch the video of the installation of the first 330 kV underground cable line in Estonia: https://www.youtube.com/watch?v=z2wN3YsUQhs&ab_channel=CORSICASOLE

Future Kiisa battery park: https://bit.ly/414n8U2

About Evecon 

Evecon is an Estonian energy company whose main activity is the construction of wind, solar and battery parks in Estonia, Latvia and Lithuania. By now, Evecon has completed renewable energy development projects with a production capacity of 59 MW. By 2024, Evecon will build an additional 200 MW capacity alone or as part of joint ventures. Additionally the company has 850 MW of active solar electricity projects and 900 MW of wind projects under development in Estonia, Latvia and Lithuania, which will be connected to the electricity grid by the end of 2026 and 2027. 

Evecon produces green energy for a cleaner future.  

For more information: https://en.evecon.ee/ 

About Corsica Sole 

CORSICA SOLE is an independent producer of solar energy and leader in energy storage in Europe.  

Growing, the company now has more than 120 MWp of photovoltaic power plants and more than 160 MWh of power plants with energy storage in operation and is developing a portfolio of projects of more than 1.5 GW. It is also developing in the field of renewable hydrogen production. Specialist in island areas since 2009, Corsica Sole develops, builds, finances, operates its own projects, in France and throughout Europe. Corsica Sole deploys its know-how to provide through renewable energies and technological innovation a relevant response to the energy transition for the fight against climate change. More information on www.corsicasole.com. 

Follow us on LinkedIn: www.linkedin.com/company/corsicasole  on X (formerlyTwitter): @CorsicaSole and on our YouTube channel: @corsicasole 

About Mirova 

Mirova is a global asset management company dedicated to sustainable investing and an affiliate of Natixis Investment Managers. At the forefront of sustainable finance for over a decade, Mirova has been developing innovative investment solutions across all asset classes, aiming to combine long term value creation with positive environmental and social impact. Headquartered in Paris, Mirova offers a broad range of equity, fixed income, multi-asset, energy transition infrastructure, natural capital and private equity solutions designed for institutional investors, distribution platforms and retail investors in Europe, North America, and Asia-Pacific. Mirova has been active in the energy transition infrastructure sector for 20 years and has financed more than 1,000 projects for a total of over 7.3 GW of potential generation capacity across 48 countries. Mirova and its affiliates had €31.1 billion in assets under management, of which €3.8 billion for energy transition infrastructure investments as of June 30, 2024. Mirova is mission-driven company, labeled B Corp. 

Mirova Energy Transition 5 (MET5) is a French limited partnership (société de libre partenariat), closed to new subscription. Mirova is the management company. The supervisory authority approval is not required for this fund. The fund is exposed to capital loss risk, market risks, industrial and public counterparty risk, credit risk, liquidity risk, project risk, operational risk, compliance risk, legal and regulatory risk, financial risk, electricity transmission and distribution network risk, valuation risk, deal flow risk, sustainability risk. The fund benefits from support from the European Union under the InvestEU Fund.