“The southern trend is economically viable regardless of the consumption profile. There is no one right direction. The choice depends on whether you want to maximize the self-sufficiency or profitability of electricity generation, ”says Altti Meriläinenelectrical engineering research assistant at LUT University.
According to LUT’s study, the photovoltaic system should be directed to the south if surplus electricity is to be sold to the grid at spot prices. The spot price is the hourly price in the Nord Pool electricity market in the Finnish trade zone. However, if the goal is to maximize self-sufficiency, the system should be two-way, such as southeast and southwest.
The east-west trend could lead to the loss of up to 15% of the revenue from the photovoltaic system compared to the south-facing system.
The study applied the Energy Agency’s updated customer class load profiles as the first research data. The load profiles consisted of measurement data from Finnish electricity companies. In addition, the study utilized simulations of solar electricity production in southern Finland and Nord Pool’s average hourly prices per day in Finland. Results are calculated from hourly data.
The sale of solar electricity to the grid is currently profitable
In previous studies, LUT has also looked at the cost-effective sizing of photovoltaic systems and the profitability of electricity storage.
“In small houses, the best or most profitable solution is to oversize the photovoltaic system. In larger buildings, 100% self-consumption is the cheapest option. On the other hand, profitability would not collapse from surplus, says the assistant professor Antti Kosonen From LUT University.
Kosonen’s research shows that self-use of solar electricity has already been cost-effective at 2016–2020 electricity prices. At current prices, selling it has also become profitable.
“Solar electricity production costs about 5 to 8 cents per kilowatt hour, and the price of electricity has now risen to about 20 cents per kilowatt hour. In other words, the system pays for itself quickly, Kosonen continues.
In addition, storing surplus electricity in batteries is not practical – network storage is more cost-effective. Network storage refers to the use of the electricity network as storage: selling surplus electricity to the network and buying it back if necessary.
More than 40,000 Finnish households produce solar electricity
Solar electricity is booming in Finland. At the beginning of 2022, there were more than 40,000 photovoltaic installations in Finland, and the number is constantly growing. In 2021, solar electricity accounted for about 0.4% of Finland’s electricity production. In other words, there is growth potential.
The European Commission has proposed that solar modules be made mandatory in public, commercial and private buildings by the end of this decade. LUT University’s research takes a stand on how the roofs of buildings should be oriented in Finland in order to get the most out of photovoltaic systems.
– Photovoltaics must be taken into account in building architecture, as it is the simplest and cheapest way to generate electricity locally, Kosonen points out.
Meriläinen adds that gabled houses should be built on a sloping side to the south or almost to the south. Chimneys and other shading elements should be located to the north of the roof.
LUT is a leading university in energy research
- This bulletin is based on three photovoltaic studies conducted at LUT University:
- Optimization of roof photovoltaic installations to maximize returns in Finland based on customer-class load profiles and simulated production
- Optimal dimensioning of a photovoltaic plant with measured electrical load curves in Finland
- Technical and economic viability of energy storage concepts combined with the household photovoltaic system: a case study from Finland
- Other LUT University photovoltaic studies:
- LUT energy reportin a commentary published in June on the role of solar electricity in Finland’s future energy system
Source: LUT University
Source: The Nordic Page