---
title: "2-52 weeks ahead Transmission System Demand and surplus forecast (TSDFW)"
method: GET
path: "/datasets/TSDFW"
tags: ["BMRS Datasets"]
---

# 2-52 weeks ahead Transmission System Demand and surplus forecast (TSDFW)

`GET /datasets/TSDFW`

This endpoint provides the Transmission System Demand forecast received from NGESO.
Data is available from 4pm each Thursday and will show values for the 2 to 52 weeks ahead.
Expressed as an average MW value for each week. The forecast is based on historically metered generation output for Great Britain.
This value INCLUDES transmission losses, but EXCLUDES interconnector flows and demand from station.

This API will provide a maximum data output range of 366 days.

Specific publish time filters may be supplied, otherwise this will retrieve the latest published forecast.

## Query parameters

- `publishDateTimeFrom` string, date-time
- `publishDateTimeTo` string, date-time
- `format` 'json' | 'xml' | 'csv'

## Response `200`

Data retrieved

- InsightsApiModelsResponsesDatasetResponse1InsightsApiModelsResponsesDemandForecastDatasetRowsDemandForecastTransmissionWeekly
  - `data` InsightsApiModelsResponsesDemandForecastDatasetRowsDemandForecastTransmissionWeekly[], nullable
    - `dataset` string, nullable
    - `publishTime` string, date-time
    - `year` integer
    - `week` integer
    - `demand` integer, nullable

## Other responses

- `400` — Error with query parameters - see response for details
- `429` — Too many requests
- `500` — Server error - please try again later

---

[API](https://skmtc.net/elexon/apis/bmrs-insights.md) · [All operations](https://skmtc.net/elexon/apis/bmrs-insights/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/elexon/bmrs-insights/versions/d94e9edb295e/schema)