Capacity factors for solar and wind power in the latest DST release

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A new release of the S2S4E Decision Support Tool sees the addition of two new energy indicators for the solar and wind energy sectors.

It is well known that renewable energy generation depends on the meteorological conditions, such as wind speed for wind energy and solar radiation for solar energy production. Another important factor affecting how much power can be produced is the installed capacity of the power plant, e.g. the number and type of installed wind turbines.

To allow for a fair comparison between different plants, energy indicators known as capacity factors are widely used, which show the power generation at a given period of time divided by the maximum production possible if the plant was operating at full capacity during this period (Lledó et al, 2019).

Capacity factor prediction

Sub-seasonal and seasonal predictions of capacity factors can be important for operation planning in the wind and solar energy sector. These forecasts can be used by a variety of renewable energy operators, irrespective of the size and type of their plants.

As part of the S2S4E project, researchers from the Barcelona Supercomputing Centre (BSC) and the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) have developed improved predictions for wind and solar capacity factors. These are available in the latest version of the S2S4E Decision Support Tool (DST), released in October 2020.

Wind and solar capacity factors

For wind farms, three different capacity factors have been computed and are available in the DST, which account for technological differences in the turbine designs, including turbines suitable for high, medium and low mean wind speeds. These capacity factors indicate the amount of utilisation of a plant, from 0% to 100%.

In the case of solar energy, one single indicator is provided, which is the ratio of actual power to the power under standard conditions (i.e. an incoming surface radiation of 1,000 W/m² and a temperature of 25°C).

For the sub-seasonal and seasonal forecasts of the wind and solar capacity factors, daily data are used, except for the seasonal predictions for wind, for which 6-hourly data are used. However, it should be noted that these capacity factor estimates do not consider any kind of losses (electrical, curtailments, maintenance, etc.) that any plants may experience.

These factors will be explained further in the upcoming S2S4E webinar on 16 October 2020 at 11:00 CEST – register here to join the webinar. Further information can be also found in the Advanced Help section of the S2S4E DST.

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Written by: Andria Nicodemou (Barcelona Supercomputing Center)