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Proability calculations help to assess power adequacy

A simulation method based on probability calculations was introduced last winter. The method had previously been utilised for mid-term power adequacy assessments.

Looking after the power system of Finland – and keeping generation and consumption in balance – requires lessons to be learnt from the past and forecasts to be made for the future. Historical hourly data is available for the past three decades or more, and hourly forecasts are made for the next ten years.

“Power adequacy analyses under ENTSO-E are prepared for the short- and long-term. In Finland, the analysis that attracts the most interest is the Winter Outlook, which is always prepared for the following winter,” says Esa Äärynen, Specialist at Fingrid.

The methods for estimating electricity consumption and the adequacy of generation have improved at pace in recent years. Äärynen says that the main reason for developing these ­methods is the increase in power generated from renewable sources that are dependent on the weather, especially wind power, and the decline in regulating power generated from fossil fuels.

“For example, the Winter Outlook traditionally used addition and subtraction. The adequacy of energy generation has been estimated by adding together the available capacities of generation plants and cross-border ­connections and then subtracting an estimate of peak consumption in the winter. Alongside this, a new method has been introduced using probability calculations and market simulations,” he says.

The transition phase is currently underway, and the traditional and new methods are being used side-by-side. In the future, the simulation model based on probability calculation will be developed more also in ERAA analyses stretching further into the future.

“In the future, long-term analyses in ERAA will be able to take into consideration the impacts of climate change on electricity generation and ­consumption. Furthermore, the analysis will include an economic viability assessment. In other words, it will provide an estimate if the forecasted generating capacity trends are feasible. When the new method is fully in use, we will use it to simulate the next ten years; this year, we will analyse target years 2025 and 2030,” Äärynen explains.

How it works

Historical data on the weather conditions, including wind speeds, temperatures and hours of sunshine, is analysed. These variables help to define distinctive generation and consumption profiles for different regions.

“Based on the profiles, we can estimate the conditions at different times: how much energy would be generated in these conditions using different capacities? Similarly, consumption patterns are estimated based on temperatures. In the market simulation, demand-side response is guided by the price. Furthermore, the calculations take into consideration the ­frequency of forced outages at power plants and interconnectors,” Esa Äärynen says.

Finally, the weather and fault profiles are used to simulate the market and assess whether the amount of electricity will be sufficient in the future. This provides a highly comprehensive estimate of the future.

“In the next Winter Outlook, the prevailing circumstances are entered into the market ­model. Planned outages are taken into ­consideration, and the estimates will be as accurate as ­possible. Naturally, estimates reaching ten years into the future contain more assumptions about the development of the electricity system,” he says.


(European Network of Transmission System Operators for Electricity)

A collaboration organisation for European transmission system operators that began operating in 2009 with the aim of developing the EU’s electricity markets and improving collaboration between transmission system operators.

Winter Outlook

A report published by ­ENTSO-E containing analyses and forecasts of the adequacy of electricity in the coming winter based on probability calculations. The analysis takes into consideration the fluctuations in electricity consumption and generation due to the weather, as well as failures in power plants and interconnectors.


(European Resource Adequacy Assessment)

A report that ENTSO-E compiles based on information provided by transmission system operators in various countries. The ERAA’s power adequacy analyses cover the coming ten years. New legislation calls for the ERAA to be used to determine the need for capacity mechanisms in the future. ERAA replaces the previous Mid-term Adequacy Forecast (MAF).


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