Latvia and Estonia Hybrid Offshore interconnector [currently known as 'Elwind']

By 4 December 2025, ELWIND had engaged EOLOS Floating Lidar Solutions S.L. under contract to conduct offshore measurement campaigns in the Estonian and Latvian wind farm areas, in three stages covering preparation, implementation, and data validation and reporting, to provide meteorological and oceanographic data that will underpin wind resource assessment and preliminary design of the offshore wind farms and their cabling, substations, and support structures within the hybrid interconnector project.

By December 2025, ELWIND had entered into a contract with Haskoning Nederland B.V. to carry out a high-level assessment of potential grid connection points and to identify cable routes and lengths, examining technical and legal aspects of connecting the hybrid offshore wind and fourth Estonia–Latvia interconnection project to the Estonian and Latvian transmission grids.

The ELWIND geophysical survey campaign by G‑Tec, started in early September 2025 in the Estonian and Latvian offshore wind areas, is planned to run for around two months, with completion of data acquisition and delivery of a ground model expected around November 2025 to inform design and installation requirements for the hybrid project.

In early September 2025, Belgian contractor G‑Tec mobilised its survey vessel Karina and began geophysical seabed investigations in the Estonian and Latvian ELWIND offshore wind farm areas, collecting data to characterise site geology and support the design of the wind farms and the associated fourth Estonia–Latvia hybrid interconnection.

In August 2025, Belgian offshore survey specialist G‑Tec won a contract worth slightly over EUR 3.6 million to carry out geophysical surveys for the ELWIND project, with its vessel Karina tasked to investigate the seabed in the Estonian and Latvian offshore wind farm areas and develop a ground model to inform design and installation for the hybrid offshore wind and interconnector development.

By July 2025, Elering had submitted the Environmental Impact Assessment (EIA) programme for the planned marine section of the fourth Estonia–Latvia electricity interconnection to the Consumer Protection and Technical Regulatory Authority (CPTRA) for approval. The programme defines the scope of studies for the offshore cable system, which will comprise up to three 330 kV AC cables and a fibre‑optic cable with up to 1,000 MW capacity between southwest Saaremaa and Latvia, and is a prerequisite for CPTRA’s EIA process within the ongoing building‑permit procedure.

CPTRA scheduled a public consultation on the EIA programme for the marine section of the fourth Estonia–Latvia electricity interconnection, with comments invited from 7 to 28 July 2025 and a public discussion on 7 August 2025 at Lümanda House in Saaremaa. The consultation allows stakeholders and the public to review and provide feedback on the planned scope of environmental studies for the offshore cable from southwest Saaremaa toward Latvia, including assessments of seabed conditions, biodiversity, fisheries, maritime transport and potential transboundary impacts.

On 18 February 2025, during a Cabinet of Ministers meeting, the Government of Latvia designated a 200 km² offshore area for research by the Latvian Investment and Development Agency (LIAA) for the ELWIND offshore wind park, a joint Latvia–Estonia project that also envisages establishing the fourth electricity interconnection between the two countries. The relocation and formal designation of this research area further offshore reduces biodiversity and visual impacts while authorising the detailed studies needed to assess the suitability of the site for the hybrid offshore wind and interconnector development.

On 18 February 2025, during a Cabinet of Ministers meeting, the Latvian Investment and Development Agency (LIAA) reported that, together with the Estonian Environmental Investment Center, it was actively running procurements for ELWIND project studies, with proposals already evaluated for bird and bat surveys and additional research procurements announced for seals, meteorology, geology, unexploded ordnance, and archaeological investigations to support development of the cross‑border offshore wind areas and the planned fourth Estonia–Latvia electricity interconnection.

On 8 May 2024, Elering submitted a building permit application to the Estonian Consumer Protection and Technical Regulatory Authority (TTJA) for the construction of the marine cable forming the offshore section of the fourth electricity interconnection between Estonia and Latvia. The application covers a subsea cable route from the southwest coast of Saaremaa towards Latvia and triggers a permitting process that includes a mandatory Environmental Impact Assessment due to potential effects on the seabed and Natura 2000 sites.

The fourth Estonia–Latvia interconnection forming the grid backbone for the ELWIND hybrid offshore wind project was included in ENTSO-E’s Ten-Year Network Development Plan 2024 (TYNDP-2024), alongside related strengthening projects, further confirming its role in the planned Baltic Sea offshore grid and supporting access to EU co-financing.

The fourth Estonia–Latvia interconnection associated with the ELWIND hybrid offshore wind project was included in the European Commission’s 2023 list of Projects of Common Interest / Projects of Mutual Interest (PCI/PMI), a designation that makes the project eligible for future Connecting Europe Facility (CEF) co-financing for its transmission infrastructure.

In October 2023, Estonian TSO Elering submitted an application to the Ministry of Regional Development and Agriculture to initiate a designated national spatial plan for the Estonian part of the fourth Estonia–Latvia power connection, planned from the Paide substation through Muhu Island to the Sõrve peninsula on Saaremaa. The spatial plan will determine whether and how it is expedient to construct this section of the hybrid interconnector, including assessment of technical options and impacts on nature and local communities.

In October 2023, AST and Elering signed a memorandum of understanding setting out principles and next steps for developing the fourth Estonia–Latvia electricity interconnection, confirming that the project will be implemented as a high‑voltage AC hybrid link with a planned Latvian connection point near Ventspils and an implementation horizon to around 2035.

In a July 2023 update, the Latvian Investment and Development Agency (LIAA) announced that a public consultation on the ELWIND offshore wind project, which includes planning for cross-border transmission network connections between Latvia and Estonia, was scheduled for August 2023. Ahead of the consultation, information seminars were to be held in Jūrkalne and Pāvilosta to inform local residents about the offshore wind sites and associated grid and interconnection studies.

The European Climate, Infrastructure and Environment Executive Agency (CINEA), under the EU Connecting Europe Facility (CEF Energy) programme, approved a grant of approximately EUR 18.7 million for the Estonian‑Latvian ELWIND hybrid offshore wind and fourth Estonia–Latvia interconnection project. The funding supports pre‑development activities including environmental studies of the designated offshore wind farm areas in Latvian and Estonian waters and planning of the cross‑border transmission network connections between the offshore sites and the onshore grids, enabling the project to progress towards permitting and later construction.

The fourth Estonia–Latvia electricity interconnection, developed as part of the ELWIND hybrid offshore wind and interconnector project, was included in ENTSO-E’s Ten-Year Network Development Plan 2022 (TYNDP-2022), recognising it as a priority transmission reinforcement needed to integrate the planned offshore wind capacity and strengthen cross-border capacity between Estonia and Latvia.

In 2022, AST and Elering completed a detailed onshore right‑of‑way study for possible onshore connection options and prepared a technical catalogue study to assess available technologies, solutions, and indicative costs for the offshore transmission infrastructure needed for the ELWIND hybrid project and the associated fourth Estonia–Latvia interconnection.

In 2022, the European Commission awarded ELWIND, the joint Estonian‑Latvian hybrid offshore wind and interconnector project, a Connecting Europe Facility (CEF) Energy grant for studies, as one of two cross‑border renewable projects (alongside CICERONE) sharing a total of €22 million. The funding supports environmental impact assessment, geological and sea basin research, spatial planning and front‑end engineering to advance the ELWIND hybrid offshore wind park and associated Latvia–Estonia interconnection.

In October 2022, Estonia and Latvia selected the deployment locations in their respective maritime areas for the joint ELWIND offshore wind project, which includes development of a fourth interconnection that will connect the offshore wind farms while also supporting cross‑border electricity trade between the two countries.

In August 2022, the Latvian Cabinet of Ministers approved a report setting national conditions for implementing the ELWIND hybrid project in Latvia, confirming that the fourth Estonia–Latvia interconnection will be realised as a hybrid scheme combining an offshore wind farm, an offshore interconnection between the Latvian and Estonian wind farm areas, and connections to the onshore 330 kV transmission grid.

On 28 April 2021, Latvian TSO Augstsprieguma tīkls (AST) and Estonian TSO Elering signed a cooperation agreement to jointly study solutions for connecting the planned ELWIND offshore wind project and associated fourth Estonia–Latvia interconnection to the mainland transmission networks, including investigations of preliminary offshore transmission line routes on the west coasts of Latvia and Estonia.

On 18 September 2020, the Latvian Ministry of Economics and the Estonian Ministry of Economic Affairs and Communications signed a memorandum of understanding that launched the joint ELWIND offshore wind project, under which Latvian and Estonian agencies develop offshore wind areas and transmission system operators AST and Elering are tasked with developing the necessary power transmission infrastructure, including a new interconnection between Estonia and Latvia to connect up to 1 GW of offshore wind generation to the grid.

As part of the environmental impact assessment (EIA) programme submitted for the marine cable of the fourth Estonia–Latvia interconnection, Elering has planned a wide range of marine and environmental surveys, including underwater archaeology, seabed geology and sediments, water quality and turbidity, biodiversity and habitats, birdlife, underwater noise, electromagnetic fields, thermal effects, fisheries, maritime transport, and impacts on protected areas and climate.

The EIA programme for the marine cable of the fourth Estonia–Latvia electricity interconnection includes planned surveys for unexploded ordnance (UXO) along the subsea route from southwest Saaremaa towards Latvia to assess and mitigate munitions-related risks during cable installation and operation.

The Environmental Impact Assessment (EIA) programme for the Estonian marine area of the ELWIND project, describing the full EIA process including the scope and methodology of environmental studies and community involvement, was submitted by the project developer to the Estonian authority TTJA, initiating formal environmental impact assessment for the ELWIND Estonian offshore area.