IESO approves new data obligations for renewable facilities

18 juillet 2011

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Beginning November 1, 2011, many wind and solar PV generators will be required to submit real-time meteorological and output data to the IESO.

The market rule amendment is part of IESO plans for renewable integration. As part of this integration, the IESO is seeking to implement centralized forecasting. Instead of providing energy forecasts, renewable facilities will be required to submit real-time, site specific data (“dynamic data”) to the IESO that will be used to produce variable generation forecasts provided by a third-party.

The requirements will apply to all wind and solar facilities connected to the IESO-controlled grid in addition to embedded non-market participants with an installed capacity over 5MW.

Starting November 1, 2011 these facilities will be required to submit both site-specific data in addition to their own forecasts. Once the IESO has implemented its central forecasting approach, renewable generators will no longer be required to submit their own forecasts. However, there is no indication from the IESO of an exact date centralized forecasting will be implemented.          

Of particular note, the market rule amendment specifies reporting standards. 

In addition to dynamic data, both wind and solar facilities will be required to provide information concerning the physical layout and details of the facility (“static data”) at the time of connection assessment and/or registration. A summary of these collection requirements are found below.


For wind facilities, the following static and dynamic data will be required:

 Static Data  Description
 Turbine Hub location  Turbine Hub location (latitude and longitude), height, and elevation from sea level.
 Meteorological (MET) Tower location  Physical location (latitude and longitude), height, and elevation from sea level.
 Type of turbine  Whether the turbine is a horizontal or vertical axis type.
 Manufacturer’s power curve  Power curve maps containing expected output for a turbine at varying wind speeds.
 Cut in speed  The lowest wind speed (metres per second [m/s]) at which the turbine will generate power.
 Cut out temperature  The maximum and minimum ambient temperature (in °C) at which the wind turbine will be shut down to prevent physical damage.


Dynamic Data Unit of Measure Height of Measurement Precision (to the nearest…)
Wind Speed Metres per Second (m/s) Hub height 0.1 m/s
Wind Direction   Degrees from True North Hub height 1 degree
Ambient Air Temperature Degrees Celsius (°C) Hub height or 2m 0.1 °C
Barometric Pressure Hectopascals (HPa) Hub height or 2m 60 Pa
Relative Humidity Percentage (%) Hub height or 2m 1.0%
MW outputs (per facility) Megawatt (MW) N/A 0.1 MW
Available Megawatts Megawatt (MW) N/A 0.1 MW


Additionally, the IESO had mandated collection standards for dynamic data listed above. At minimum, each facility will be required to provide this data from nacelle mounted data collection points. Every turbine is required to be within 5km from the nearest data collection point. Furthermore, each facility over 10MW will be required to provide data from at least one standalone meteorological tower. The number of towers required will correspond to the facility size (MW). Towers will be required located on the prevailing upstream side of the wind facility in areas that have representative microclimates and winds at hub height. Data is to be reported to the IESO in real-time every 30 seconds.


For solar facilities, the following static and dynamic data will be required:

Static Data Description
Solar facility location (latitude and longitude) Physical location (GPS coordinates) of each solar array.
Meteorological data collection device location and elevation (latitude and longitude) Physical location (GPS coordinates) of each met data collection device, its elevation and height of measurement.
Elevation and orientation
angles of arrays
Height from ground level and angle of each solar array, Tilt (angle with horizontal plane) and Azimuth (angle in North-East-South West Plane)
Power Rating Rated Power at standard test conditions.
Generation capacity of the generating facility and each generating unit The name plate capacity of the entire facility with a breakdown for each array within the system. (DC and AC Power at standard test conditions for arrays and power of inverters.)
Temperature Coefficient Temperature coefficient of the module power at the maximum power point,
Type of Mounting Ground Mount, Rooftop, Rack Mount, Fixed or Solar Tracking etc
Module Type Crystalline, Thin-Film, Concentrated PV (CPV) etc


Measurment Type Definition Unit of Measure Data Required for Measurment Precision
Plane-of-Array Irradiance (POA) Measurements perpendicular to the solar receiver Watts/ Square Meter Crystalline, Thin-Film, CPV +/- 25W/m2
Global Horizontal Irradiance (GHI) The solar resource available to a flat-plate collector oriented horizontal to the earth’s surface Watts/ Square Meter Crystalline, Thin-Film, CPV +/- 25W/m2
Global Diffused (GDIFF) Solar radiation that has been scattered out of the direct beam Watts/ Square Meter CPV +/- 25W/m2
Direct Irradiance (DNI) The amount of solar radiation received per unit area by a surface that is always held perpendicular (or normal) to the rays that come in a straight line from the direction of the sun at its current position in the sky. Watts/ Square Meter CPV +/- 25W/m2
Ambient temperature at the average height of the array Ambient temperature at the array average height Degrees Celsius (°C) Crystalline, Thin-Film, CPV   1 °C
Back of Module Temperature Average temperature at the back of module Degrees Celsius (°C) Crystalline, Thin-Film, CPV 1 °C
Barometric pressure Barometric Pressure Pascals (Pa) Crystalline, Thin-Film, CPV 60 Pa
Wind speed and direction at the average array height Anemometer, wind vane or wind mast readings Meters/Second (m/s) Crystalline, Thin-Film, CPV 1 m/s
MW output (per facility) Current Megawatt (MW) output for the facility  Megawatt (MW) Megawatt (MW)  Crystalline, Thin-Film, CPV 0.1 MW
Available Megawatts What the facility can produce after deducting outages Megawatt (MW) Crystalline, Thin-Film, CPV 0.1 MW


Like wind, solar will be subject to data collection standards. At minimum, each facility will be required to have two meteorological data collection points. All solar arrays in that facility are required to be within 12km of a collection point. Data must be provided to the IESO every 30 seconds.

For both wind and solar PV, there is no requirement that the data collection devices be owned by the same owner of the facility.

Stakeholder Engagement

These new obligations are part of a larger IESO plan to accommodate the phase-out of coal and increased contribution of wind and solar. These developments will significantly impact Ontario’s electric grid. Declining demand and variability associated with renewable sources could result in a surplus of baseload generation. Furthermore, the IESO is facing a reduced flexibility to deal with the variability of supply due to increased regulatory constraints and limited ramping ability of gas facilities (compared to coal).

In an attempt to accommodate this variability, the IESO will implement changes to three major areas: forecasting, visibility and dispatch. The IESO is currently undertaking stakeholder engagement initiative (SE-91) in an effort to include stakeholders, such as developers and distributers, in the talks surrounding these changes.

Currently, eleven design principles have been approved relating to the three areas of change. This amendment is based upon SE-91 Renewable Integration Final Design Principles - Principles 1, 4 and 5. 

The Ontario Power Authority (OPA) is watching SE-91 closely. It has committed to working with supplies on OPA contract issues that may result from these IESO rule amendments (RESOP, RESIⅈ RESIII, FIT, HCI).

In any event, the IESO will continue consulting with stakeholders in renewable integration. Currently, two working groups for SE-91 exist: the Dispatch Technical Working Group and the Visibility Technical Working Group. This fall, the IESO intends to form a dispatch merit order working group that will comment on the order of curtailment in the event of baseload surplus.

For more information on SE-91 or to participate in the next meeting, email [email protected]

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