Interconnected power systems play an essential role to ensure the secure and stable operation of the transmission network, as well as to support the functioning of competitive electricity market. Latvia's power system is currently interconnected with Estonia and Lithuania, but it has no direct interconnections with other European countries.
Due to Latvia's geographical location, it has the potential to establish a connection with Sweden, which would ensure the integration of the Latvian and Swedish electricity transmission systems. Considering the synchronization of the Baltic energy systems with continental Europe, the significant increase of renewable energy resources (RES) in both Latvia and Sweden, as well as the ongoing challenges related to system security, operation stability and market operation, these issues remain relevant for both the Baltic and Nordic regions.
To deeply evaluate these issues and assess the feasibility of an interconnection between Latvia and Sweden, the Latvian transmission system operator AS "Augstsprieguma tīkls" (hereinafter – AST) conducted a study on the Latvia-Gotland-Sweden interconnection project, named the LaSGo (Latvia-Sweden-Gotland Island) link. The aim of the study was to evaluate the possible technological solutions, route options and connection options of the LaSGo project, its impact on the electricity transmission networks in both countries, power flows, static and dynamic stability calculations, cost-benefit analysis, as well as key economic and financial indicators. The study was conducted in 2024, and the results were presented to all involved parties at the beginning of 2025. The study was carried out by the Italian energy consultant – CESI S.p.A. by request from AST side.
Study content and objectives
The High Voltage Direct Current (HVDC) project is a submarine cable direct current interconnection between Latvia and Sweden, which includes two stages: the first is a 700 MW internal line from Sweden to the island of Gotland, while the second stage is an interconnection between the island of Gotland and Latvia, with a planned capacity of 700 MW as well.
The LaSGo project is a significant energy infrastructure development project that will provide technical, environmental and economic benefits, including increasing the security and stability of energy supply in the region, increasing the competitiveness of the electricity market in the Baltic States and the Nordic countries, and facilitating the integration of renewable energy generation resources in Latvia and Sweden, including offshore and onshore wind energy, on the island of Gotland in particular. It will promote the use of hydrogen technologies for green hydrogen production in both countries and will help to operate and manage potential RES generation amounts in all involving countries and in particular on the island of Gotland, as well as improve the security of electricity supply of all involved energy systems and guarantee secure and stable system operation.
The following tasks were performed in the Latvia-Sweden interconnection study:
- Technological analysis to evaluate the current state of HVDC technologies and determine the most suitable configuration of the LaSGo project, as well as to calculate the planned costs of the LaSGo project.
- Network analysis to evaluate the LaSGo link impact to the transmission networks and to determine possible network reinforcement or capacity re-dispatching actions.
- Market analysis to evaluate the LaSGo link impact to the electricity markets of the power systems of Latvia and Sweden and to prepare a cost-benefit analysis to demonstrate the economic profitability of the project.
The study was prepared based on network and market modelling and using network and market models in Latvia and Europe.
The detailed analyses carried out in the study showed the viability and benefits of the LaSGo project for both Latvia and Sweden, where Swedish side was informed about study results during meeting between AST, the Swedish TSO Svenska Kraftnat and the study consultant. AST and Svenska Kraftnat agreed to continue cooperation on project development.
The study concluded that by connecting of LaSGo project to the Kurzeme region in Latvia, the reinforcement of the internal Latvian transmission network is essential from network security and system stability point of view, and the 330kV line Ventspils-Brocēni-Varduva project in Latvia will help ensure the secure and stable operation of the Latvian power system with LaSGo. The analysis prepared for 2040 considered some increased load situations under normal conditions and overloads N-1 conditions, however, this can be mitigated using the advanced methods considered in the study, making new additional network reinforcements unnecessary. In addition, the LaSGo interconnection increases socio-economic benefits in both countries, will allow for better management of RES energy, optimizing hourly dispatching or limiting RES energy if necessary, and will allow for a reduction in expected CO2 emissions in Latvia (approximately -35%, corresponding to 68 kt). Prepared study concluded, that LaSGo link operation is expected in both directions, allowing the benefits of various production expansion plans across the two connected countries.
On the Swedish side, the LaSGo project also brings network operation benefits, for example for the island of Gotland, which currently has a limited capacity transmission network and a rather old connection to the Swedish grid. Considering the expected development of RES production and consumption on the island of Gotland, the LaSGo project will increase security and stability of the island with provision of electricity supply to the island from both sides, helping to avoid from investments in new onshore transmission networks on the Gotland island or limiting them. In this context, the LaSGo interconnection is one of the potential key elements to ensure full security of energy supply from a 2 sides. In other words, the available capacity (imported and domestic renewable energy production) is bigger than the demand on Gotland at all hours of the year. The LaSGo interconnection also allows for the optimization of hourly dispatching in Sweden (mainly hydro power generation) and the reduction of potential curtailments of RES energy production. Thanks to the availability of renewable energy in the Baltic region and the LaSGo interconnection, it is possible to support Sweden in planning an earlier decommissioning of the ageing fleet of Swedish nuclear power plants.