wattprice

What does electricity cost right now under Spain's regulated PVPC tariff? wattprice asks the ESIOS API — the data service run by Red Eléctrica de España — for the PVPC (Voluntary Price for the Small Consumer) indicator and returns the prices payload as JSON, for a date range and geographical area you choose.

Everything except the API key itself is optional, with the defaults the upstream documents:

• locale — es (default) or en

• startDate / endDate — ISO 8601 bounds; an absent range means today, start to end of day

• timeAggregation — sum (default) or average

• timeTruncation — hour, day, month, or year

• geographicalAggregation — sum (default) or average

• geographicalIds — string IDs: 3 España, 8741 Península, 8742 Canarias, 8743 Baleares, 8744 Ceuta, 8745 Melilla; defaults to the five system IDs 8741–8745

• geographicalTruncation — country or electric_system

Configuration

You bring your own ESIOS API key (free registration at esios.ree.es):

export ESIOS_API_KEY="your key"

Without it, wattprice does not guess: the call fails with an error naming ESIOS_API_KEY, and no prices are invented. ESIOS_API_BASE overrides the API base URL (https://api.esios.ree.es by default).

Related MCP server: Datadis MCP Server

CLI

ESIOS_API_KEY=... npx @reneturcios/wattprice prices
ESIOS_API_KEY=... npx @reneturcios/wattprice prices --locale en --time-truncation day --geographical-ids 8741
npx @reneturcios/wattprice --version

Output is the ESIOS prices payload as JSON. Exit codes: 0 on success, 1 on a runtime error (including a missing key or a non-200 upstream response), 2 on a usage error.

MCP server

npx -y @reneturcios/wattprice mcp

MCP client config:

{
  "mcpServers": {
    "wattprice": {
      "command": "npx",
      "args": ["-y", "@reneturcios/wattprice", "mcp"],
      "env": { "ESIOS_API_KEY": "your key" }
    }
  }
}

Tools

• fetch_prices — Fetch PVPC prices for a given date range and geographical area. All arguments are optional; see the defaults list above.

Docker

docker run -i -e ESIOS_API_KEY="your key" ghcr.io/cloudcorprecords/wattprice
docker run --rm -e ESIOS_API_KEY="your key" ghcr.io/cloudcorprecords/wattprice prices --locale en

Development

npm install
npm run build   # tsc -> dist/
npm test        # tsx --test test/*.test.ts (fake fetch, no network)
npm run dev     # run the CLI from source

License

MIT — Copyright (c) 2026 Rene Turcios