The energy system in Finland
Finland is a Nordic country with cold and dark winters, and mild summer weathers with long daylight hours. The country is rather scarcely populated with long transportation distances towards the North, whereas majority of the population lives in the South. Finland has historically also hosted plenty of energy intensive industry, although over the recent years industrial energy consumption growth has stopped or even decreased due to multiple industrial unit closures.
Despite high energy consumption per capita, Finland is globally also among the leading countries in the usage of renewable energy, covering approximately 40 % of energy end-use by renewables (mostly bio-based fuels).
Roughly a quarter of the total energy consumption in Finland is in the form of electricity. The annual electricity consumption of Finland peaked in 2007 at 90,4 TWh and has since varied annually in the range from 81 to 88 TWh. The electricity consumption is still higher at cold and dark wintertime, although the difference between summer lows and winter peaks of power has become smaller (approximate demand range 6…15 GWh/h).
From importer to self-sufficient
Finland has been a net importer of electricity in the past, relying on electricity supply from Russia as well as the ample hydro power production capacity in our neighboring countries, Sweden and Norway. Domestic electricity production has covered 76…88 % of demand in 2010-2020.
The electricity generation fleet in Finland has always been rather uniformly mixed, consisting of hydro power, nuclear power, conventional condensing power, combined heat, and power (both district heating and industrial CHP) – none of the production forms being too predominant. Recently there has also been an increasingly prominent share of variable renewable power production, i.e., wind and solar.
Wind power capacity in the Finnish power system has increased quite rapidly from <1 % to almost 10 % share of electricity demand coverage over approximately a single decade by 2020. Wind power production has replaced mainly conventional condensing power production, and several fossil fuel-fired condensing power plants have been shut down.
One of the largest nuclear power plant units in the world, Olkiluoto 3 in South-Western Finland with 1 600 MW capacity, is to be in operation in near future. Olkiluoto 3 shall produce approximately 13 TWh/a, thus improving energy self-sufficiency in Finland dramatically. With this substantial amount of new power production in the electricity market, more variation in power transmission is foreseen to be taking place on North-South connections within Finland, as well as on the cross-borders with the neighboring countries.
The power transmission in Finland can be characterized by long distances with heavy North-to-South power transmission. Also, a large share of power import from other Nordic countries takes place on the North-South connections. Furthermore, the best wind power potential, and majority of wind power plants in operation and in planning, are located in the area or vicinity of these major power transmission corridors, posing additional challenges to the power transmission system.
The transmission system of Finland is part of the Nordic synchronous power system, and Finland has also DC interconnections in the South to Russia, Estonia, and Sweden. Despite its remote geographic location, the power system of Finland has good existing electricity pathways, and further being reinforced, with the whole European interconnected power system enabling cross-border electricity exchange and benefiting the whole European energy targets.
The purpose of the national power system
The national power system is built to function reliably, efficiently, and flexibly whilst responding to fluctuating electricity consumption. Finland’s electricity quality criteria ensure that local reliability is maintained when a new power plant is connected to the grid. In addition, the Finnish power system is capable of monitoring fluctuating consumption levels continuously at a national level, even in the event of a sudden disturbance. The organization responsible for the power system, Fingrid, is also tasked with ensuring that grid transmission capacity is sufficient for transporting large amounts of locally produced energy to wherever the electricity consumption is required. Fingrid participates in the EU’s energy efficiency project by strengthening the main grid according to the new energy solutions.
Balancing and reserve power are required to ensure the system is functional. The main balancing power in Finland is hydropower or electricity purchased from neighboring countries. With the advancement of technology and electricity pricing, consumers can also play an active role in regulating the electricity system by for example storing electricity in the battery of their electric car, when electricity is low due to abundant supply and limiting consumption when electricity demand is high.
In Portugal and Ireland, where wind power covers more than 25% of annual electricity consumption, the increased use of variable power has increased the use of balancing power. It is expected that also in Finland, additional construction of wind power will increase the use of balancing power and contribute to encouraging consumers to participate in flexible consumption for example customers can use automation to time their electricity consumption moments.
The balancing and reserve power supply serves the entire electrical system, as well as all electricity producers. By adding or replacing small portions with different forms of production, the existing system can be used as it is.
Grid effects
All electricity producers and consumers connected to the network have some effect on electricity quality. Good electricity quality means that the supply is uninterrupted, the electricity amplitude and frequency are stable, the waveform is a sine wave, and the voltage level is appropriate.
Distribution networks are traditionally designed to transmit electricity from the substations to the consumers. When individual wind turbines or a small wind park are connected to a distribution network, it is important to ensure that the voltage stays within accepted values throughout the network and that network security functions correctly. In the event of a network fault, the wind turbine generator disconnects from the network automatically and stops production, so that it does not hinder the interruption of arc faults or continue electrification of an isolated part of the network, which would endanger returning the network to a normal state.
Transmission of electricity causes power losses. When wind turbines are located near consumers, less transmission is required and therefore power losses decrease.