---
title: "Balancing Services Volume (QAS) stream"
method: GET
path: "/datasets/QAS/stream"
tags: ["BMRS Datasets"]
---

# Balancing Services Volume (QAS) stream

`GET /datasets/QAS/stream`

This endpoint provides Balancing Services Volume data received from NGESO.
            
Balancing Services Volume is a volume which is received from the System Operator, which represents the volume
of energy (MWh) associated with the provision of Applicable Balancing Services for each relevant BM Unit and
Settlement Period.

QAS can be positive or negative and is normally only provided where there is a non-zero volume.
            
By default, the from and to parameters filter the data by time inclusively. If the settlementPeriodFrom or
settlementPeriodTo parameters are provided, the corresponding from or to parameter instead filters on settlement
date, allowing for searching by a combination of time and/or settlement date & settlement period.
Note: When filtering via settlement date, from/to are treated as Dates only, with the time being ignored. For
example, 2022-06-01T00:00Z and 2022-06-01T11:11Z are both treated as the settlement date 2022-06-01.
            
All Dates and DateTimes should be expressed as defined within
<a href="https://datatracker.ietf.org/doc/html/rfc3339#section-5.6" target="_blank">RFC 3339</a>.
            
Some examples of date parameter combinations are shown below.
            
Filtering from start time to start time:
            
    /datasets/qas/stream?from=2022-06-01T00:00Z&to=2022-07-01T00:00Z
            
Filtering from start time to settlement date and period:
            
    /datasets/qas/stream?from=2022-06-01T00:00Z&to=2022-07-01T00:00Z&settlementPeriodTo=1
            
Filtering from settlement date and period to start time:
            
    /datasets/qas/stream?from=2022-06-01T00:00Z&to=2022-07-01T00:00Z&settlementPeriodFrom=1
            
Filtering from settlement date and period to settlement date and period:
            
    /datasets/qas/stream?from=2022-06-01T00:00Z&to=2022-07-01T00:00Z&settlementPeriodFrom=1&settlementPeriodTo=1

This endpoint has an optimised JSON payload and is aimed at frequent requests for QAS data.

## Query parameters

- `from` string, date-time, required
- `to` string, date-time, required
- `settlementPeriodFrom` integer
- `settlementPeriodTo` integer
- `bmUnit` string[]

## Response `200`

Data retrieved

- InsightsApiModelsResponsesBalancingDatasetRowsBalancingServicesVolumeData[]
  - `dataset` string, nullable
  - `settlementDate` string, date
  - `settlementPeriod` integer
  - `bmUnitApplicableBalancingServicesVolume` number, double
  - `nationalGridBmUnit` string, nullable
  - `bmUnit` string, 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)