gramm Forecast API

The gramm 24-Hour Load Forecast API provides seamless access to grid demand predictions for California utilities in the CAISO market context. Designed to align with familiar CAISO OASIS parameter conventions, utilities can integrate forecast data into existing workflows with minimal changes.

Supported Utilities

The following CAISO Transmission Access Charge (TAC) areas are supported:

TAC Area	Utility	Service Territory	Status
`PGE`	Pacific Gas & Electric	Northern & Central California	Active
`SCE`	Southern California Edison	Central & Southern California	Active
`SDGE`	San Diego Gas & Electric	San Diego Region	Active
`VEA`	Valley Electric Association	Eastern California / Nevada Border	Active

Base URL

https://api.gramm.ai/forecast/v1

Authentication

All API requests require an API key provided in the request header:

Authorization: Bearer YOUR_API_KEY

To obtain an API key, contact api@gramm.ai.

Endpoints

GET /demand

Retrieve 24-hour ahead load forecast for a specified utility TAC area.

Request Parameters

Parameter	Type	Required	Description
`tac_area`	string	Yes	TAC area code: `PGE`, `SCE`, `SDGE`, `VEA`
`startdatetime`	datetime	Yes	Start time: `YYYYMMDDTHH:MM-0000` (e.g., `20250101T00:00-0800`)
`enddatetime`	datetime	Yes	End time: `YYYYMMDDTHH:MM-0000` (e.g., `20250102T00:00-0800`)
`market_run_id`	string	No	Market run: `DAM` (Day-Ahead), `RTM` (Real-Time), `2DA` (2-Day Ahead)
`resultformat`	integer	No	`5` = XML (default), `6` = CSV, `7` = JSON
`version`	integer	No	Data version (default: latest)

Example Request

curl -X GET "https://api.gramm.ai/forecast/v1/demand?\
tac_area=PGE&\
startdatetime=20250101T00:00-0800&\
enddatetime=20250102T00:00-0800&\
market_run_id=DAM&\
resultformat=7" \
-H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "meta": {
    "tac_area": "PGE",
    "utility": "Pacific Gas & Electric",
    "startdatetime": "20250101T00:00-0800",
    "enddatetime": "20250102T00:00-0800",
    "market_run_id": "DAM",
    "units": "MW",
    "generated_at": "20241231T16:00-0800",
    "model_version": "megfs-v2.1"
  },
  "forecast": [
    {"interval_start": "20250101T00:00-0800", "value": 18542.3, "lower_bound": 17890.1, "upper_bound": 19194.5},
    {"interval_start": "20250101T01:00-0800", "value": 17891.7, "lower_bound": 17259.4, "upper_bound": 18524.0}
  ]
}

GET /historical

Retrieve historical forecast accuracy metrics.

Request Parameters

Parameter	Type	Required	Description
`tac_area`	string	Yes	TAC area code
`date`	date	Yes	Date in `YYYY-MM-DD` format
`metric`	string	No	Metric type: `mape`, `rmse`, `mae` (default: all)

GET /tac-areas

List all supported TAC areas and their current status.

Rate Limits

Plan	Requests/Hour	Requests/Day
Trial	100	1,000
Standard	1,000	10,000
Enterprise	Unlimited	Unlimited

Familiar API Design

The gramm API uses parameter conventions familiar to CAISO OASIS users, making it easy to integrate forecasts alongside historical grid data:

CAISO OASIS	gramm Forecast API	Notes
`queryname=SLD_FCST`	`GET /demand`	System Load Forecast
`market_run_id=DAM`	`market_run_id=DAM`	Same parameter name
`startdatetime`	`startdatetime`	YYYYMMDDTHH:MM-0000
`enddatetime`	`enddatetime`	YYYYMMDDTHH:MM-0000
`resultformat=5`	`resultformat=5`	XML output
`resultformat=6`	`resultformat=6`	CSV output

Support

API Status: status.gramm.ai
Contact: api@gramm.ai

CAISO and OASIS are trademarks of their respective owners. References are for interoperability and benchmarking context only and do not imply endorsement.