AESO
AESO Energy Merit Order Report API

A snapshot of the energy merit order — the stacked offers that determine which generation is dispatched and where the price clears — served from /meritOrder/energy. This is bid-and-offer transparency data of the kind most system operators publish only on a lag.
Documentation GitHub OpenAPI
OpenAPI Specification

{
  "openapi": "3.0.1",
  "info": {
    "title": "Energy Merit Order Report",
    "description": "Fetch Energy Merit Order snapshot data",
    "version": "v1"
  },
  "servers": [
    {
      "url": "https://apimgw.aeso.ca/public/energymeritorder-api"
    },
    {
      "url": "https://gateway-apim.aeso.ca/public/energymeritorder-api"
    }
  ],
  "paths": {
    "/meritOrder/energy": {
      "get": {
        "operationId": "getMeritOrderReport",
        "summary": "Fetch Energy Merit Order snapshot data for a given date that is 60 days prior to current date.",
        "description": "Fetch Energy Merit Order snapshot data for Date(startDate (yyyy-MM-dd)) \n\nThe EMMO snapshot data is available 60 days after the date of the snapshot, first available from September 1, 2009. \n\nThe data from 1-Sep-2009 to 1-Sep-2014 is the Merit Order at the 30th min. of the settlement interval. \n\nThe data after 1-Sep-2014 is the last Merit Order of the settlement interval.\r\n",
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/EnergyMeritOrderReport"
                },
                "examples": {
                  "default": {
                    "value": {
                      "data": [
                        {
                          "begin_dateTime_utc": "string",
                          "begin_dateTime_mpt": "string",
                          "energy_blocks": [
                            {
                              "import_or_export": "string",
                              "asset_ID": "string",
                              "block_number": 0,
                              "block_price": 0,
                              "from_MW": 0,
                              "to_MW": 0,
                              "block_size": 0,
                              "available_MW": 0,
                              "dispatched?": "string",
                              "dispatched_MW": 0,
                              "flexible?": "string",
                              "offer_control": "string"
                            }
                          ]
                        }
                      ]
                    }
                  }
                }
              }
            }
          },
          "400": {
            "description": "Bad Request"
          },
          "401": {
            "description": "Unauthorized"
          },
          "403": {
            "description": "Forbidden"
          },
          "404": {
            "description": "Not Found"
          },
          "405": {
            "description": "Invalid method"
          },
          "500": {
            "description": "Internal server error"
          },
          "503": {
            "description": "Service unavailable"
          }
        },
        "parameters": [
          {
            "name": "startDate",
            "in": "query",
            "required": true,
            "description": "Any date between 2009-09-01 and 60 days prior to current date (format: yyyy-MM-dd).",
            "schema": {
              "$ref": "#/components/schemas/MeritOrderEnergyGetRequest"
            }
          }
        ]
      }
    }
  },
  "components": {
    "securitySchemes": {
      "apiKeyHeader": {
        "type": "apiKey",
        "name": "API-KEY",
        "in": "header"
      },
      "apiKeyQuery": {
        "type": "apiKey",
        "name": "subscription-key",
        "in": "query"
      }
    },
    "schemas": {
      "EnergyMeritOrderReport": {
        "type": "object",
        "properties": {
          "data": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/MeritOrderData"
            }
          }
        }
      },
      "MeritOrderData": {
        "type": "object",
        "properties": {
          "begin_dateTime_utc": {
            "type": "string",
            "description": "Beginning of the settlement hour that the Energy Market Merit Order applies to, in Coordinated Universal Time (UTC) time"
          },
          "begin_dateTime_mpt": {
            "type": "string",
            "description": "Beginning of the settlement hour that the Energy Market Merit Order applies to, in Mountain prevailing time"
          },
          "energy_blocks": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/EnergyBlocks"
            }
          }
        }
      },
      "EnergyBlocks": {
        "type": "object",
        "properties": {
          "import_or_export": {
            "type": "string",
            "description": "Import/Export Identifier, either 'I' for Import or 'E' for Export"
          },
          "asset_ID": {
            "type": "string",
            "description": "Asset's unique short name defined by 3 or 4-digit alphanumeric code. A pool asset is registered to a pool participant."
          },
          "block_number": {
            "type": "integer",
            "description": " Block Number from 0 to 6",
            "format": "int32"
          },
          "block_price": {
            "type": "number",
            "description": "Block Offer Price (in $/MWh)",
            "format": "double"
          },
          "from_MW": {
            "type": "integer",
            "description": "Prior Block's cumulative Megawatt (in MW)",
            "format": "int32"
          },
          "to_MW": {
            "type": "integer",
            "description": "Current Block's cumulative Megawatt (in MW)",
            "format": "int32"
          },
          "block_size": {
            "type": "integer",
            "description": "Block Size (MW)",
            "format": "int32"
          },
          "available_MW": {
            "type": "integer",
            "description": "Available Megawatts for the System Controller to Dispatch (in MW)",
            "format": "int32"
          },
          "dispatched?": {
            "type": "string",
            "description": "Dispatched MW indicator - either 'Y' for Yes or 'N' for No"
          },
          "dispatched_MW": {
            "type": "integer",
            "description": "Dispatched Megawatts (in MW)",
            "format": "int32"
          },
          "flexible?": {
            "type": "string",
            "description": "Flexible block indicator -'Y' indicates that the System Controller is able to partially dispatch the block, 'N' indicates they can not"
          },
          "offer_control": {
            "type": "string",
            "description": "Offer Control - Offer control parties separated by a semi-colon"
          }
        }
      },
      "MeritOrderEnergyGetRequest": {
        "pattern": "^\\d{4}\\-(0[1-9]|1[012])\\-(0[1-9]|[12][0-9]|3[01])$",
        "type": "string",
        "x-apim-inline": true
      }
    }
  },
  "security": [
    {},
    {
      "apiKeyHeader": []
    },
    {
      "apiKeyQuery": []
    }
  ],
  "x-provenance": {
    "harvestedBy": "API Evangelist",
    "harvestedOn": "2026-07-27",
    "sourcePortal": "https://developer-apim.aeso.ca/",
    "method": "Assembled verbatim from the AESO Azure API Management developer-portal data API, which is served anonymously. AESO's own OpenAPI export (?export=true&format=openapi) returns a valid document with an EMPTY paths object, so paths, parameters, responses, examples and component schemas were read from the portal's operations/ and schemas/ endpoints and reassembled without alteration. Nothing was invented.",
    "sources": [
      {
        "url": "https://developer-apim.aeso.ca/developer/apis/energymeritorder-api-v1?api-version=2022-04-01-preview",
        "status": 200,
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  }
}
AESO Energy Merit Order Report API

Documentation

Specifications

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OpenAPI Specification
