# National Energy System Operator (NESO)

> NESO is Great Britain's publicly owned, operationally independent electricity system operator and whole-energy system planner. It runs two live, fully anonymous public APIs: the NESO Data Portal API (CKAN 2.8.7, 128 open datasets on GB electricity demand, generation, balancing, constraints, interconnectors, connection registers, network charges and Future Energy Scenarios) and the Carbon Intensity API for Great Britain (national and regional carbon intensity, forecast up to 48 hours ahead, half-hourly generation mix and per-fuel emission factors). No API key, no registration, no application. Generated by API Evangelist from the NESO catalog entry; NESO does not publish an llms.txt.

## APIs

- [NESO Data Portal API](https://www.neso.energy/data-portal/api-guidance): CKAN Action API 3 at https://api.neso.energy/api/3/action - package_list, package_search, package_show, organization_list, tag_list, resource_search, resource_show, datastore_search, datastore_search_sql (read-only PostgreSQL). Anonymous.
- [Carbon Intensity API](https://carbon-intensity.github.io/api-definitions/): REST/JSON at https://api.carbonintensity.org.uk - 33 documented GET paths across national intensity, statistics, generation mix and regional breakdowns by DNO region, region id or postcode. Anonymous.

## Docs

- [Data Portal](https://www.neso.energy/data-portal): dataset catalogue and browse UI.
- [API guidance](https://www.neso.energy/data-portal/api-guidance): supported CKAN actions, SQL query examples, rate guidance.
- [Carbon Intensity API reference](https://carbon-intensity.github.io/api-definitions/): full path and schema reference (Slate).
- [Carbon Intensity forecast methodology](https://github.com/carbon-intensity/methodology): how the forecast is produced.
- [Carbon Intensity terms of use](https://github.com/carbon-intensity/terms)
- [NESO Open Data Licence](https://www.neso.energy/data-portal/neso-open-licence): v1.0, derived from OGL v3.0, compatible with CC BY 4.0. All 128 datasets carry it.
- [Responsible disclosure](https://www.neso.energy/responsible-disclosure): vulnerability disclosure policy (no monetary rewards).

## Specs

- No OpenAPI, Swagger, GraphQL, AsyncAPI or gRPC contract is published by NESO on any host. Probed 2026-07-27 across api.neso.energy, api.carbonintensity.org.uk and carbon-intensity.github.io.

## Artifacts (API Evangelist)

- [Authentication](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/authentication/neso-authentication.yml): both APIs anonymous; no key, OAuth, OIDC or mTLS.
- [Conventions](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/conventions/neso-conventions.yml): pagination, filtering, SQL, error envelopes, CORS, change detection.
- [Rate limits](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/rate-limits/neso-rate-limits.yml): 1 request/second to the CKAN API, 2 requests/minute to the Datastore API - advisory, enforced by IP blocking.
- [Error codes](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/errors/neso-error-codes.yml): live-probed error bodies for both surfaces.
- [Lifecycle](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/lifecycle/neso-lifecycle.yml): CKAN Action API 3; Carbon Intensity unversioned; no status page, SLA or deprecation policy.
- [Conformance](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/conformance/neso-conformance.yml): CKAN Action API 3, ISO 8601, CORS, RFC 9116, OGL v3.0, Ofgem Data Best Practice; no energy-sector data standard.
- [Data model](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/data-model/neso-data-model.yml): Organization/Package/Resource/DatastoreRecord and IntensityPeriod/Region/GenerationMix.
- [MCP candidate](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/mcp/neso-mcp.yml): 17 candidate tools over the two APIs. NESO operates no MCP server.
- [Packages](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/packages/neso-packages.yml): no first-party SDK on any registry.
- [Well-known](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/well-known/neso-well-known.yml): security.txt on www.neso.energy; nothing elsewhere.
- [Agent skills](https://raw.githubusercontent.com/api-evangelist/neso/refs/heads/main/skills/_index.yml): packaged operating instructions for the marquee flows.

## Rules for agents

- Send no credentials. Both APIs are anonymous; an Authorization header is unnecessary and ignored.
- Respect the published rate guidance: at most 1 request per second to the CKAN API and 2 requests per minute to the Datastore API. NESO blocks IP addresses that degrade the service.
- Do not poll data files for change. Call resource_show?id={resource_id} and compare last_modified before fetching.
- Everything is read-only. There is no public write operation on either API, and no idempotency contract exists because none is needed.
- Attribute redistributed Data Portal data as "Supported by National Energy SO Open Data".
- Times are ISO 8601 UTC and the native grain is the GB half-hour settlement period.
- There is no consumer or customer data here. NESO holds no retail relationships; GB smart-meter consumption data moves through the Smart DCC, not the system operator.

## Notes

- generated: 2026-07-27
- method: generated
- source: apis.yml + repo artifacts (NESO publishes no llms.txt; https://www.neso.energy/llms.txt returned 404 on 2026-07-27)