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The IESO is taking steps to efficiently integrate variable generation into the supply mix –which includes solar and wind generation that is connected to local distribution networks. An estimated 2,400 megawatts (MW) of embedded solar and wind generation are expected to be in service by February 2015. This increasing amount of embedded generation is impacting provincial grid conditions, and could pose a challenge in forecasting and operating the power system as these facilities exist outside the traditional sightlines of IESO operations.

By putting in place a forecast for embedded wind and solar generation, the IESO will have a more accurate picture of the whole power system – better and more accurate information means better and more efficient decisions when operating of the grid.

Forecasting Embedded Generation Output

The IESO is now actively registering all embedded variable generators larger than 5 MW with the IESO’s centralized forecasting service. Currently, the IESO receives a centralized forecast of all transmission-connected variable generation output, using output and telemetry data gathered at each facility as well as numerical weather models. This forecast, expanded to embedded generation equal or greater than 5 MW, will help IESO operators to better account for generation in the province, maintain reliability and efficiency of the system, and provide transparency of the elements that make up the daily demand forecast.

The IESO’s centralized forecasting service is published on the Variable Generation Forecast Report. It includes a forecast of all transmission-connected variable generation and currently, the forecast of a portion of embedded variable generation in the province. As more facilities register with centralized forecasting in the coming months, the forecast will improve. The IESO will also be publishing the real-time output values of the embedded facilities as more become available.

Embedded variable generation facilities larger than 5 MW must register with the IESO prior to reaching commercial operation. For more information on data requirements, operational monitoring, training and registration, visit

Generators (and LDCs with embedded generators) can contact Market Entry  or  Customer Relations  for more information.




As of September 2013, about 530 MW of embedded variable generation have registered for centralized forecasting.

Embedded variable generation facilities larger than 5 MW must register with the IESO prior to reaching commercial operation.

To register your facility, visit or contact Market Entry or Customer Relations