2016-01 / STEADYMET / powergrid management

January 25th, 2016

Forecast for a power plant of 7 MW in India.

At the end of 2015, India counts more than 4.6 GWp of photovoltaic plants. This park should reach 10 GWp before March 2017. The need to plan for the integration of this renewable production becomes imperative.

The example given below is the one of a 7 MW power plant.

January the 25th is a day well brightened up in the morning, with cloudy spells in the afternoon. The latter must be relatively fine because they partly allow some direct irradiation; otherwise one would have deeper falls of production.

Solar forecasting India - 1 day ahead - Timestep 1 min

Figure 1: Actual (in blue) vs Forecast (in orange) – 1 day ahead, time step: 1 minute


The forecast is almost perfect in the morning. In the afternoon, there are, not surprisingly, larger gaps given the variability of the production. The forecast remains on the high part of the intermittencies.

The precision remains high, with an error which does not exceed 12.5 % of the peak power on a of 15 minute time step. Thus, the forecast is within the +/- 25 % limits required by the grid operator which avoids the developer to be exposed to financial penalties.


Solar forecasting India - 1 day ahead - witn nMAE - Timestep 15 min

Figure 2: Actual (in blue) vs Forecast (in orange) – nMAE (in green – figure below) – 1 day ahead, time step: 1 minute