---
title: "Loss of load probability and de-rated margin (LOLPDRM)"
method: GET
path: "/datasets/LOLPDRM/stream"
tags: ["BMRS Datasets"]
---

# Loss of load probability and de-rated margin (LOLPDRM)

`GET /datasets/LOLPDRM/stream`

The loss of load probability and de-rated margin data is received half-hourly from NGESO.
            
Loss of load probability (LoLP) is a measure of system reliability, calculated by NGESO for each settlement period,
using the methodology set out in the Loss of Load Probability Calculation Statement.
            
De-rated margin is a forecast of the excess supply on the system, which has been adjusted to take account of the likely availability of electricity generators.

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

## Query parameters

- `publishDateTimeFrom` string, date-time, required
- `publishDateTimeTo` string, date-time, required

## Response `200`

Data retrieved

- InsightsApiModelsResponsesMiscDatasetRowsLossOfLoadProbabilityDeratedMarginData[]
  - `dataset` string, nullable
  - `publishTime` string, date-time
  - `publishingPeriodCommencingTime` string, date-time
  - `startTime` string, date-time
  - `settlementDate` string, date
  - `settlementPeriod` integer
  - `lossOfLoadProbability` number, double, nullable
  - `deratedMargin` number, double, nullable

## Other responses

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

---

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