Electricity system of Finland
The power system in Finland consists of power plants, nation-wide transmission grid, regional networks, distribution networks and electricity consumers. The power system in Finland is part of the inter-Nordic power system together with the systems in Sweden, Norway and Eastern Denmark. Moreover, there are direct current transmission links to Finland from Russia and Estonia for the connection of their systems, which work under different principles, to the Finnish power system. Similarly, the inter-Nordic system is connected to the system in Continental Europe by means of direct current transmission links.
Fingrid is responsible for the functioning of the Finnish electricity transmission grid. The transmission grid is the high-voltage trunk network which covers the entire Finland. Major power plants, industrial plants and regional electricity distribution networks are connected to the grid.
The transmission grid administered by Fingrid encompasses approx.
• 4,600 km of 400 kV transmission lines (kV = kilovolt = 1,000 volts)
• 2,200 km of 220 kV transmission lines
• 7,600 km of 110 kV transmission lines
• 116 substations.
The transmission grid serves electricity producers and consumers, enabling trading between them on a nation-wide level and also across national boundaries. Most of the electricity consumed in Finland is transmitted via the nation-wide transmission grid.
Fingrid is responsible for system supervision, operation planning, balance service, grid maintenance, construction and development, and promotion of the electricity market.
Between 2015 and 2025, Fingrid will spend a total of 1,200 million euros on upgrading the transmission grid, which means annual capital expenditure around 110 million euros. The objective is to build almost 3,000 kilometres of new transmission lines and about 30 new substations. The grid capital investment programme covering the whole of Finland is based on the long-term climate and energy strategy of Finland. This aims to reduce the greenhouse gas emissions, shift from a dependence on electricity imports to self-sufficiency, and replace electricity generation based on fossil fuels. The objective in electricity generation is to increase nuclear power, renewable energy – in other words forest energy – and wind power. The transmission grid must be able to receive the new production, but the development of the grid is also affected by other factors, such as changes in electricity consumption, decommissioned production capacity, and renovations required by the existing grid.
High voltage levels are used in the transmission grid because of the long transmission distances and so as to reduce the losses inevitably arising in electricity transmission at high transmission powers. There does not appear to be a need to adopt higher voltage levels in Finland.
The transmission grid in Finland has primarily been built with air insulation, in other words the substations are installed outdoors and the transmission lines are overhead lines. The use of underground cables is limited, because they are prohibitively expensive with the long transmission distances typical of Finland and because they restrict land use in areas where the cable is installed. When existing substations are expanded or if the available space is very limited, so-called gas-insulated switching stations are used, where the live components are enclosed in a metal casing containing pressurised insulating gas.
In order to accomplish sufficient transmission capacity and system security in an as efficient and economically viable manner as possible, the adoption and development of new technologies is studied continuously. This normally takes place through research and development projects.
Regional networks are connected to the nation-wide transmission grid and distribute electricity regionally usually on one or more 110 kV lines. Distribution networks are either connected directly to the nation-wide grid or use the grid services via a local network. The distribution networks operate at a voltage level of 0.4 to 110 kV. Households are linked to distribution networks. Industries, trade, services and other consumption (e.g. agriculture) are connected to a distribution or regional network or to the nation-wide transmission grid, depending on each individual case.
Power plants are connected to a distribution or regional network or to the nation-wide transmission grid as appropriate in each case.