Transmission & distribution
Sweden-Lithuania HVDC link takes a step forward1 May 2010
Planning, feasibility study and calls for tender phases have now been completed and a TSO agreement reached for construction of the NordBalt (formerly SwedLit) project to connect more strongly the transmission systems of the Nordic and Baltic countries.
In March this year the CEOs of the transmission system operators Lietuvos Energija AB and Svenska Kraftnät signed a co-operation agreement for implementation of the NordBalt power link project between Sweden and Lithuania. The agreement is to define the conditions under which TSOs will jointly implement the project by interconnecting the two electricity systems.
This co-operation will consist of three key stages – the link‘s development, construction and post-construction stages. It was agreed that ownership of the infrastructure resulting from the construction of the power bridge will be split at the seagoing halfway popint. Lietuvos Energija will own the converter station at Klaipeda, the cable stretching from Klaipeda substation to the sea, and 50 % of the submarine cable. The rest of the cable and the link‘s infrastructure on Swedish territory will be owned by Svenska Kraftnät. The connection point in Lithuania is Klaipeda 330 kV substation, and in Sweden the Nybro 400 kV substation.
The deal also includes an agreement regarding the link‘s funding and the conditions as well as how the prospective EU financial support allocated to the construction of the link will be used. This EU support totals r131 million, out of a total cost for the power link estimated at r552 million. The two TSOs have now formed a steering committee to co-ordinate and supervise project implementation.
In December 2009 Marin Mätteknik AB successfully completed the sea bed survey and in early April this year the technical specifications and tender documents prepared by technical consultant Vattenfall Power Consultant AB were sent out to prequalified potential suppliers.
Implementation of the project would facilitate integration of the Baltic States in the power market of Northern Europe and would significantly increase security and reliability of power supply in the region. The Lithuanian national energy strategy describes the state's main priorities and its implementation guidelines for the year 2025; its goals include ensuring strategic security of the country’s power supply and integration of its electricity sector into the EU power market, both of which are favoured by implementation of the project. The interconnection is a part of the Baltic Interconnection Plan approved by the European Commission.
The 450 km interconnection will be rated at 700 MW. Its subsea section will be HVDC, with HVDC connections to the converter substations, with AC overhead lines thereafter at both ends of the link. The possibility of connecting offshore wind farms in future is also foreseen.
In 2007 Svenska Kraftnät and Lietuvos Energija engaged SWECO International to carry out a feasibility assessment from market, technical and environmental standpoints. Several ratings up to 1000 MW were assessed. Sweco concluded that co-operation between countries around the Baltic Sea is evolving in many areas and also within the energy sector, and that improved electrical transfer capacities between countries would be a partial solution to the problem of efficiently distributing generation capacity within the EU, and would improve the efficiency of electricity markets. The possibility of connecting wind farms along the route of the link supported the EU imperative of increasing the amount of renewable energy produced within its borders. The market analysis was based on a 700 MW HVDC classic cable transmission and covered trade among all the surrounding countrie in the Nordic and Baltic regions. Attention was also paid to the possibility for power transiting.
In the later part of 2007 the second part of the feasibility study was started. It covered technical issues as well as the possibility of applying for EU funding, and was to propose suitable procedures for procuring the interconnection. A recommended solution, regarding preferred technology and size, was identified and presented.
The main objective of the technical part of the study was to identify a preferred solution regarding the size/capacity of the link and the most suitable HVDC technology, that is, classic or VSC. In the event it was recommended that the link be built with VSC technology. This recommendation was based mainly upon peceived advantages in operation and connection, although project ongoing cost was considered slightly cheaper on the classic side (mainly owing to much lower losses).