2017-06 / Solar PV plant with storage in an insular grid


June 7th, 2017

Solar PV plant with storage in an insular grid

In the Martinique Island (French oversea territory in the Caribbean), the grid stability can be seriously affected by the variability of the solar PV production. The larger-scale integration of this energy, will go with the addition of storage capacities and an adapted management system which integrates forecasts of the solar production over several time scale.

For this 100 KWc PV plant, Steadysun has deployed a comprehensive solution based on weather models and satellite images.

On June 7, 2017, the forecast provided the day before has under-estimated the production.
It is a day presenting a strong variability of production bound to numerous cloudy spells and a fast evolution of the cloud layer.

Figure 1: actual (in blue) vs SteadyMet forecasts of the day before

During the day, this forecast is updated every quarter of an hour thanks to satellite images what allows to refine the production profile for the 30 minutes to come.

One can notice on figure 2, that the accuracy is improved.

Figure 2: actual (in blue) vs intraday satellite based forecasts (in red) – 60 minutes ahead – minute time step

When averaging this profile at a 15 minutes time step (figure 3), the accuracy performance appear more clearly as compared with Figure 2 which is at one minute time step.

Figure 3: actual (in blue) vs intraday satellite based forecasts (in red) – 60 minutes ahead, averaged on a 15 minutes time step

With such a display, available through Steadysun customer interface, one can manage the storage system with a better efficiency, by defining the day before the optimized level of state of load to start the operation on the next day as well as the injection profile of the next day to be announced to the grid operator.
During the day, the asset manager may appeal the stored energy at best to maximize the income.