Capacity Margin

Capacity Margin is the difference between the reliable available generation capacity and the peak load.


By now the following forecast values were predicted within the scope of the "Winter Outlook Report 2020/2021". Since ENTSO-E just performs probabilistic calculations in the upcoming winter report the values enclosed were calculated by APG following the method used in the past.

Capacity margin 2021 (GW) 
 1 Net generating capacity (NGC)  23,47*
 2 Unavailable capacity due to maintenance, overhauls, mothballed plants, wind power, solar and hydro power "under severe conditions" 14,32
 3 Reliable available capacity (1 - 2) 9,15
 4 Outages and system services reserve  0,82
 5 Planned reliable available capacity (3 - 4) 8,33
 6 Forecast peak load 9,14
 7 Remaining capacity (5 – 6)  -0,81


For every week in the period from November 2020 to March 2021 a different capacity margin was calculated. Thus, the shown values correspond to the week with the lowest capacity margin. For climate depending generation (wind, PV, hydro power) and for the load the 50 percentile values out of 35 climate years were considered. That means that 50 % of these values are higher or lower.


The limited working capacity of the hydro (pumped)-storage power plants is taken into account by assuming average precipitation and a normal pumping behavior. Afterwards, the determined energy is divided by the standard operating hours of (pumped)-storage power plants. This approach ensures a sustainable storage management throughout the year.


Extreme situations (e.g. floods or droughts) as well as future market related power plant shutdowns and mothballing (as far as not known at the time of drawing the report) were not taken into account in this analysis. Thus, under such conditions, the remaining capacity would decrease and the Austrian dependency on imports would rise. 


More information about the “Winter Outlook Report” and the “Mid term-Adequacy Forecast” of ENTSO-E see the following links:


* The power plants "Upper Ill-Lünersee" of Illwerke AG (with an installed capacity of approximately 1.7 GW) and the power plant “Kühtai/Silz” (with an installed capacity of approximately 0.8 GW) are not included. Although those lie on Austrian territory, they are assigned to the German control block.