Emission Factors

emission-factors MCP server

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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).

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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.

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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.

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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.

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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

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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.