Energy accumulation and storage development in Lithuania

Energy accumulation and storage development process has already started in Lithuania. However, energy storage projects (both electricity and heat) are so far focused on energy storage and balancing for short-term – daily or weekly periods only.

Electricity sector

Lithuania, Latvia and Estonia have seamlessly disconnected from the Soviet-era Russian electricity system and started operating in isolated mode and synchronized their electricity grids with Western Europe. The disconnection was carried out in two phases, starting on 8 February 2025, with the disconnection from the Russian grid and the Baltic countries working in a single isolated grid. The second phase took place on 9 February, with the Lithuania-Poland interconnection to the European system. This marked the start of a new phase in energy life, allowing us to be self-sufficient and resilient to unforeseen situations. The European system has more safeguards, as all countries can ensure the reliability of electricity supply on their own and can lend a helping hand to each other when needed.

The process of synchronisation with the European network is just beginning. The Baltic countries will need to get used to the new system, and intensively learn to manage their frequency, balance and other system quality parameters, among which electricity and accumulation are among those important [1].

National Agenda “National Strategy for Energy Independence” (hereinafter referred to as “the Strategy”) has been developed to implement fundamental changes in the energy in the energy sector – to ensure that Lithuania produces enough energy resources, as much as it consumes, and to make the energy sector fully neutral by 2050 2050. The changes implemented will enable the economy to accelerate development and contribute to the growth of society’s well-being, while ensuring national security interests.

The Strategy will lay the foundations for a major turning point in the energy sector – the transition from fossil fuels, the burning of which emits carbon dioxide, to clean and renewable energy sources, mainly electricity. It is the transition from oil and gas to electricity will require the biggest changes in energy production, its transmission and consumption. The uneven and unpredictable nature of renewable energy infrastructure will need to be flexible, able to store surplus energy and ensure uninterrupted supply to all consumers.

Achieving the objectives set out in the Strategy will help to fully prepare the already the changes already underway and maintain a stable and secure energy system Lithuania [2].

The first national-level storage – Kruonis Pumped Storage Hydroelectric Power Plant (KPSHP) – started operation in 1984 for the needs of Ignalina Nuclear Power Plant. After the closure of Ignalina in 1991 it is operating for the needs of the National Power System [3].

Managed by Ignitis Gamyba, KPSHP is situated north of the town of Kruonis in Kaišiadorys district and is the only power plant of its type in the Baltic region. KPSHP is used primarily to balance electricity supply and demand. It helps to prevent energy system accidents and liquidates their aftermath. Currently, KPSHP can ensure 94% of the total necessary energy reserves for Lithuania in case of emergency.

During periods of low demand, usually at night, the KPSHP is operated in pump mode and uses cheap surplus energy. It raises water from the lower Kaunas Lagoon to the upper 303 ha reservoir 100 m above the Kaunas Lagoon water level. During peak-demand periods (daytime) with regular energy demands, it operates like a traditional hydroelectric plant. To prevent and liquidate system accidents, units need to ensure a rapid reserved capacity. KPSHP can be switched on at full power in less than 2 minutes, if necessary. The KPSHP units can be started automatically by the anti-accident system and can cover any power deficit. Other equally important functions of KPSHP are the ability to level the system load balance, regulate voltage and frequency, and start the system after a total system blackout.

Figure 1. Kruonis Pumped Storage Hydroelectric Power Plant (picture by Ignitis Group).

Technical characteristics of KPSHP:

• Capacity – 900 MW, 4 units of 225 MW
• Cycle efficient use rate: 0.74
• Unit‘s operational range in generator mode: 0 – 225 MW
• Fixed capacity in pump mode: 220 MW

The KPSHP generated 0,72 TWh of electricity in 2020 [4]. The new 110 MW unit of the Kruonis Hydroelectric Power Plant is being built to balance the RES power generation and will significantly expand the energy storage capacity of the entire Kruonis Hydroelectric Power Plant. The construction of the new unit is scheduled for completion in 2026.

The following step in energy storage was energy cells – battery park systems by Energy Cells company [5]. “Energy cells” have been installed and integrated into the Lithuanian energy system a system of four energy storage facilities, and battery parks, with a total combined capacity of 200 megawatts (MW) and 200 megawatt-hours (MWh). Energy cells have been installed in four battery parks of 50 MW and 50 MWh each at transformer substations in Vilnius, Šiauliai, Alytus and Utena. This is currently the largest project of its kind in the Baltic States and one of the largest in Europe.

Lithuania’s system of electricity storage facilities is essential to ensure the security of Lithuania’s energy system and its ability to operate in isolated mode. The system of energy storage devices will provide Lithuania with instantaneous power reserve for isolated operation until synchronisation with the Continental European grid (CET) and will be used after synchronisation for the integration of energy produced from renewable energy sources.

Figure 2. Energy storage facility – battery park. (Photo by Energy Cells)

The high-capacity energy storage system will be installed and serviced by a consortium of Siemens Energy and Fluence, which has designed, manufactured, and connected to the transmission system and will provide after-sales service and maintenance for 15 years after the system is switched on. Lithuania will have an instantaneous standby power reserve of 200 megawatts (MW) and 200 megawatt-hours (MWh) from a system of electricity storage facilities. In case of demand, the high-capacity reserve storage units will start supplying power immediately – within 1 second. This will ensure reliable delivery of active power to the grid until other sources of electricity generation come online. Lithuanian power plants currently operating in the IPS/UPS system can start providing power within 15 minutes.

Once synchronized with the continental European electricity grid (CET), the Energy Cells-managed energy storage system will be able to store and, if necessary, feed electricity generated by solar or wind power plants into the grid. Lithuania aims to generate 70% of its electricity consumption by 2030, almost half of it from renewable energy sources (RES). The growing number of solar and wind farms requires innovative and flexible measures to manage the energy system. The more RES capacity we have and the more energy we produce, the more solutions are needed to ensure the successful and efficient integration of energy from RES.

The intermittency of the power generated by RES poses challenges for system balancing and frequency management. Energy storage devices can provide frequency management reserves and additionally react to the rate of frequency variation employing synthetic inertia, thus contributing to frequency stability. Power is generated under suitable weather conditions, and this does not always coincide with the actual electricity demand. By storing surplus energy in batteries, it is possible to reduce or adapt to grid loads.

The new energy storage facilities will use climate-neutral technologies, which will contribute to the country’s climate change mitigation goals by reducing the need for more polluting sources of electricity to run the transmission system [6].

The launch of the synchronous compensators is the most important step towards consolidating Lithuania’s energy independence in February next year by disconnecting from the Russian electricity system and synchronizing with the continental European grid. Synchronous compensators are the most important equipment needed for the Baltic countries to prepare for autonomous power frequency management. They ensure the inertia of the power system and allow for quality grid voltage regulation. With the launch of the synchronous compensator, we are sending a very important message about achieving one of the two goals of energy independence.

Figure 3. The first synchronous compensator in Telšiai (Photo by lrv.lt)

A synchronous compensator is a powerful, high-mass rotating electric motor connected to the electricity grid, capable of storing rotational energy to be used as a generator when required. It helps to stabilise the frequency of the power system and increases the dynamic stability of the grid: it reduces voltage drops during short circuits, ensures inertia and compensates for reactive power. The unit, weighing more than 460 tonnes, was manufactured in Germany and installed in Lithuania by Siemens Energy.

A total of three synchronous compensators, 50 MW each, are connected to the transmission grid in Lithuania – at the Neris transformer substation in Telšiai, Alytus and Vilnius district. The Alytus synchronous compensators will be completed this year and the Neris one next year. Three synchronous compensators are planned for each of the Baltic countries. The installation of synchronous compensators is one of the main projects of the synchronisation programme with the continental European grid [7, 8, 9, 10].

State plans support 102 million Euro for high capacity batteries for juridical persons [11, 12], 15 million Euro for residential consumers [13], 18 million Euro for public bodies, businesses and farmers [14] via Environment Projects Management Agency.

District Heating and Cooling sector

Several years ago, due to the fast development of the use of woody biomass in the district heating sector, the requirement for solutions, related to the specifics of biomass installations and, the efficiency of such systems raised the importance of heat accumulations in the sector.

Container or tank-type water-based storage is the simplest and thus the most popular in Lithuania. Such storages are already constructed and/or under design and construction in large cities, towns and even small settlements all over Lithuania. Here we provide several examples.

Figure 4. The heat storage in Klaipėda City (Photo by Klaipėda Energy)

The main unit, Šilutės highway. On the territory of the main unit of AB „Klaipėdos energija“, Šilutė branch, the new construction 24 meters high appeared in 2023. It is a 3000 m³ accumulation tank for the storage of cogeneration heat carriers. The project was carried out with the financial support of the EU and contributed to the improvement of the city’s environmental situation and the reduction of heat prices.

Underneath the shiny profiled sheet metal cladding is a 30 cm thick layer of insulation material to protect the main body from heat loss. One pipe will be used to fill the tank with a thermal heat carrier up to 92°C, while the other pipe will discharge it into the city’s heat network as needed. The boiler house generates most of its heat from 4 boilers burning biomass fuel. But when the outside temperature is low, the heat produced by these boilers is no longer sufficient and the gas boilers have to be fired up. A storage capacity of 3000 m³ will allow the company to store more heat from cheaper fuels and reduce the use of natural gas.

The experts who prepared the feasibility study for the project estimate that the savings in natural gas used for heat generation will amount to more than 15,000 megawatt hours (MWh) per year. From an environmental point of view, the storage capacity will help to reduce the greenhouse effect, with over 2 900 tonnes less carbon dioxide (CO2) being emitted into the atmosphere each year [15].

The new 1.5 MW biomass boiler-house was supplemented with the 20 m³ storage tank to ensure the efficient and stable use of the boiler [16]. Another example is a 100 m³ storage tank in Prienai biomass boiler-house [17].

Figure 5. 20 m³ accumulation storage tank in Matuizai settlement (Photo by Varėnos šiluma)

We can also find a few examples of underground storage facilities. One of them was established in 2019 at the headquarters of Kaunas University of Technology. The hybrid energy generation and storage system were funded under SMAGRINET Powering Smart Grid Expertise In Europe project and includes 500 m³ underground energy storage (sensitive heat, filled with water, 380 kWp PV units, 170 kW heat pumps (water-to-water). This system will save over 6000 tons of CO₂ emission during a lifetime (20 years) [18].

Figure 6. Underground storage facility at KTU headquarters (Photo by KTU)

Vilnius DH company is planning two types of heat storage – underground PTES should allow accumulation of heat from co-generation during the summer period and release it in winter. The volume of such storage is estimated at 200,000 m³ with a 15 MW heat pump, which could replace 17 GWh of natural gas per year. TTES will be designed to solve short-term disturbances in the pipelines. There are at least two such storages planned 20,000 m³ at the 8th boiler-house and 4,000 m³ for heat recovery from sewerage treatment [19].

Currently, there are plans for 5.6 million Euro support subsidies for heat storage with a target of 639 MWh, other largest cities in Lithuania, such as Kaunas, Panevėžys, Alytus, etc., as well as small towns and settlements, are now designing and preparing to implement heat storage facilities. Some settlements are planning hybrid systems, like PV with batteries, and heat pumps with heat accumulation.

The new advanced heat generation and storage technology is now being implemented in Klaipėda by Lavastream, which is a geothermal power plant developer in Lithuania, working with US technology partner Sage Geosystems and other US and EU innovators. Lavastream has already raised capital for its first project in Klaipėda. Project baseline parameters: 25 MWt capacity heat generation during the heating season, 6-8 MWe/60-120 MWh in storage mode during the non-heating season. This project will lay the foundation for the future development of deep geothermal energy in Lithuania and the region. In the long term (2025-2034), Lavastream and its partners aim to develop at least a 1 GW total capacity fleet of electricity storage and generation plants in Lithuania [20].

Hydrogen

Currently, hydrogen is a new advanced type of fuel for transport. The first such hydrogen production and storage plant for municipal transport is planned in Vilnius.

Figure 7. Planned hydrogen production and storage for transport needs in Vilnius (Picture from Vilnius DH company)

Replacing 16 diesel buses with hydrogen buses will reduce CO₂ emissions by 1414 tonnes per year. As the green hydrogen will be produced using electricity from RES, the production process will have no environmental impact. The total value of the project is €8 million. 70% of the project will be financed by the European Union and 30% by Vilnius City Municipality. Vilnius’ public transport bus fleet will be renewed, with 16 new buses powered by green hydrogen, and the amount of green hydrogen produced at the power plant will allow more vehicles to be serviced [20]. Hydrogen storage systems are also important for designing hydrogen supply networks as a source of stored energy [22].

This article was prepared by Farida Dzenajavičienė.

References

1. Source:Istorinis įvykis – Lietuva tapo energetiškai nepriklausoma nuo Rusijos – Lietuvos energetikos institutas
2. National Strategy for Energy Independence, 2024.
3. Ignitis Gamyba company website: https://ignitisgamyba.lt/en
4. Ignitis Gamyba company website:Kruonis Pumped Storage Hydroelectric Power Plant (KPSHP) | Ignitis gamyba
5. Energy Cells company website: https://www.energy-cells.eu/en/
6. Energy Cells company website: Energijos kaupimo įrenginių parkai – Energy Cells
7. Source:Pradėjo veikti pirmasis sinchroninis kompensatorius – Alkas.lt ;
8. Source: Lietuva atsijungia nuo BRELL žiedo: Telšiuose įjungtas pirmasis „Litgrid“ sinchroninis kompensatorius – Delfi verslas ;
9. Source: Alytuje įjungtas antrasis iš trijų sinchroninių kompensatorių – Verslo žinios ;
10. Source: „Litgrid“ pradeda sinchroninio kompensatoriaus įrengimo projekto statybas Telšiuose – Delfi verslas
11. The Ministry of Energy of the Republic of Lithuania website: https://enmin.lrv.lt/lt/zaliau/suzinok/juridiniu-asmenu-kaupimo-sistemu-isirengimui-per-100-mln-euru/
12. The Ministry of Energy of the Republic of Lithuania website: https://enmin.lrv.lt/lt/zaliau/suzinok/102-mln-euru-paramos-kvietimas-dideles-galios-baterijoms-jau-artimiausiu-metu/
13. The Ministry of Energy of the Republic of Lithuania website: https://enmin.lrv.lt/lt/zaliau/suzinok/gyventoju-elektros-energijos-kaupimo-irenginiu-isirengimui-numatyta-15-mln-euru/
14. The Ministry of Energy of the Republic of Lithuania website: https://enmin.lrv.lt/lt/zaliau/suzinok/viesiesiems-juridiniams-asmenims-verslui-ir-ukininkams-18-mln-euru-isirengiant-energijos-kaupimo-sistemas/
15. Source:„Klaipėdos energija“: akumuliacinė talpa mažins anglies dvideginio išmetimus – Lietuvos šilumos tiekėjų asociacija
16. Valakevičius. Varėnos rajono Matuizų gyvenvietės 1,5 MW galios biokuro katilinė. UAB „Varėnos šiluma“. Presentation of Varėna DH company.
17. Source: Prienams nereikia trijų katilinių: racionaliau sutelkti pajėgumus vienoje vietoje | Gyvenimas
18. KTU Elektros energetikos sistemų katedra. Kauno technologijos universiteto indėlis į energetikos transformaciją. Presentation of KTU from Nov. 17, 2022.
19. 10 years investment plan of Vilnius DH company:VST-10-metu-investicinis-planas_Patvirtintas.pdf).
20. Valadkevičius. Geoterminė energija: siekiamybė vs. realybė. Elektros energijos kaupimas žemės gelmėse. Prasentation of Lavastream for Lithuanian Energy Institute, from Feb. 20, 2025.
21. Website of AB „Vilniaus šilumos tinklai“:Žaliasis vandenilis – AB Vilniaus šilumos tinklai
22. Website of Ambergrid (operator of the Lithuanian natural gas transmission system):https://ambergrid.lt/planuojant-vandenilio-infrastruktura-amber-grid-kviecia-versla-pasidalinti-vandenilio-rinkos-pletros-planais-lietuvoje/1124

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