emission-factors MCP server

Give Claude, Cursor, Cline, or any MCP client live access to US electricity data by ZIP code - grid-carbon emission factors, retail rates, hourly grid carbon intensity, power-plant emissions, and utility tariffs.

Backed by emission-factors.com, which wraps EPA eGRID, EIA-861, EIA-930, EPA CAMD, and OpenEI URDB into one ZIP-keyed API.

Free. No API key, no signup. The API is rate-limited per IP (2,000 requests/hour).

What you can ask

Once connected, your agent can answer things like:

• "My HQ in ZIP 94105 uses 1.2M kWh/year. What's our Scope 2 carbon footprint and annual electricity cost?"
• "Compare Denver, Austin, and Columbus for a new data center on grid carbon intensity and electricity price."
• "What hour of the day is cleanest to run a 500 kW batch job in California this week?"
• "Enrich this list of 40 store ZIP codes with each site's emission factor and carbon-free percentage."
• "Which are the dirtiest power plants in Texas by CO2 over the last week?"
• "Rank Ashburn VA, Abilene TX and The Dalles OR for a 10 MW data center on carbon and power cost."
• "Our plant burns 40,000 therms of gas and 3,000 gallons of diesel a year - what's our Scope 1?"
• "What's the actual PG&E residential tariff for 94105, not the state average?"

Why use it

• Scope 2 carbon accounting - GHG Protocol location- and market-based emission factors for 33,700+ US ZIP codes (CDP, CSRD, California SB 253 inputs).
• Site selection - compare candidate locations on both carbon intensity and electricity cost in one conversation.
• Demand-response and load-shifting analysis - hourly grid carbon from EIA-930 (fixed per-fuel factors on in-BA generation: for timing, not inventory reporting).
• Plant-level emissions - EPA CAMD data for fossil units over 25 MW: per-facility summaries or unit-hour records, published quarterly.
• Agents and automation - a clean tool surface so an LLM can fetch authoritative government data instead of hallucinating factors.

Quick start

There are two ways to run this. Most people want Option A.

Option A - Remote server (recommended, zero install)

Nothing to install, always up to date. The hosted endpoint is https://emission-factors.com/mcp (Streamable HTTP, no key).

Claude (web, desktop app, mobile) - Add to Claude. The link opens Claude's custom-connector dialog with the name and URL filled in; select Add, then Connect. By hand: Customize -> Connectors -> Add custom connector, URL https://emission-factors.com/mcp, OAuth fields empty.

Claude Code

claude mcp add --transport http emission-factors https://emission-factors.com/mcp

Cursor - add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "emission-factors": {
      "url": "https://emission-factors.com/mcp"
    }
  }
}

Cline / Continue / Zed / other clients - add a remote (Streamable HTTP) MCP server with URL https://emission-factors.com/mcp. No key needed.

Claude Desktop's claude_desktop_config.json only starts local (stdio) servers - a "url" entry there does nothing. Use the connector link above, or Option B.

Option B - Local stdio server (this package)

Runs the server as a local process that proxies the same public API. Useful for clients that only support stdio transport, or if you want to self-host.

Run straight from GitHub (builds on install, requires Node 18+):

{
  "mcpServers": {
    "emission-factors": {
      "command": "npx",
      "args": ["-y", "github:rozetyp/emission-factors-mcp"]
    }
  }
}

Or clone and run from source:

git clone https://github.com/rozetyp/emission-factors-mcp.git
cd emission-factors-mcp
npm install        # builds dist/ via the prepare script

{
  "mcpServers": {
    "emission-factors": {
      "command": "node",
      "args": ["/absolute/path/to/emission-factors-mcp/dist/index.js"]
    }
  }
}

Optional environment variable: EMISSION_FACTORS_API_BASE (defaults to https://emission-factors.com) if you run your own instance of the API.

Tools

Eleven tools, keyed by US ZIP code (or a direct code where noted). The remote server and this stdio build expose the same set.

All tools return JSON. See full API docs for exact response shapes.

Data sources

Rate limits and auth

• No API key, no signup. Every request is anonymous.
• 2,000 requests/hour per IP. Generous for interactive use; if you hit it you get an HTTP 429 with a retryAfter hint.
• The external-data endpoints are cached server-side (24h rates, 1h hourly intensity, 7d tariffs, 24h plant emissions), so repeated calls are fast and don't burn upstream quotas.

Also available

• REST API - the same data over plain HTTP: curl "https://emission-factors.com/api/lookup?zip=94105". See the API docs and OpenAPI spec.
• Hosted MCP setup guide - emission-factors.com/mcp-setup
• Machine-readable summary for agents - emission-factors.com/llms.txt

Development

npm install        # install deps and build (prepare -> tsc)
npm run build      # compile TypeScript to dist/
npm run dev        # watch mode
npm start          # run the built server over stdio

Quick smoke test with the MCP Inspector:

npx @modelcontextprotocol/inspector node dist/index.js

The server is a thin proxy: each tool maps to one /api/* endpoint on emission-factors.com, validates inputs, and returns the JSON response. There is no local state and no key handling.

License

MIT - see LICENSE. Data belongs to its respective US government sources (EPA, EIA, Census) and NREL/OpenEI; this project and the API are an unofficial wrapper, not affiliated with those agencies.