Trading : A Portfolio of Photovoltaic Solar Plants in Italy


7 September 2017

If we consider the same prevision quality, the size and compositions of a portfolio have an impact on the gaps between planned and actual power generation.

The case of September, 7th 2017 related to a portfolio of about 20 plants illustrates this point.  This is a rather chaotic day from a meteorological perspective. Here, the forecasts are delivered the day before, for the next day based on our day-ahead solar forecasting product, namely steadyMet.

For the plant number 1, production shows a dramatic drop around midday, and then a rise around 1 pm (Figure 1).

For the portfolio as a whole,  no similar event can be observed in terms of intensity (Figure 3). Gaps between the planned and actual generation remain comparatively low with an MAE –mean absolute error – twice or three times below the MAE reported for plant number 1 and plant number 2: 2.6% vs 6.7% and 4.9% .

 

Figure 1: actual production (in blue) vs production forecast of the day before (in red) – plant number 1

 

Figure 2: actual production (in blue) vs production forecast of the day before (in red) – plant number 2

 

Figure 3: actual production (in blue) vs production forecast of the day before (in red) – portfolio