Reference · built on requestCommons signalEnergy & grid

WattTime Data API

Marginal and average grid emissions rates, forecasts, and a 0-100 cleanliness index by grid region from WattTime.

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About

WattTime publishes emissions estimates for electricity grids. Its Data API serves three signals: co2_moer, the marginal operating emissions rate in lbs CO2 per MWh; co2_aoer, the average rate of the generators running at that time, weighted by output; and health_damage, the health cost of marginal generation in USD per MWh. Values are published in near real time and forecast on a rolling 72-hour horizon. A grid region is resolved from a latitude and longitude with /v3/region-from-loc. The Basic plan is free: it covers the 0-100 signal index in every region and all endpoints for the CAISO_NORTH region. Analyst and Pro subscriptions cover other regions.

An operator reads the forecast for your region and proposes moving flexible load, such as EV charging or pre-cooling, into the cleanest hours. You approve the shift, and the estimate behind it is kept for your reporting.

This is a reference listing. It documents what Fibric would read from WattTime Data API and what it could propose, based on the publisher's published interfaces. Fibric builds it under a managed deployment when you request it; selecting it here installs nothing.

Inputs

  • co2_moer, co2_aoer, and health_damage values for a region from /v3/historical, in windows of at most 32 days per query
  • The most recent forecast for a region and signal from /v3/forecast, with horizon_hours to trim the 72-hour horizon
  • The current 0-100 co2_moer percentile index from /v3/signal-index, free for every covered region
  • The grid region serving a latitude and longitude from /v3/region-from-loc
  • GeoJSON region boundaries from /v3/maps, restricted to ANALYST and PRO subscriptions
  • Which signal types, regions, endpoints, and model dates your account can query, from /v3/my-access

Proposed actions

Read-only. This feed informs operators; it changes nothing.

Proposed actions are target capabilities. Every action runs propose-first and needs a validated deployment and the appropriate permissions.

What you can build

  • Shift flexible load into cleaner hours

    Carbon Window reads the co2_moer forecast for your region, finds the lowest-emission hours inside your comfort or departure limits, and proposes the schedule change for approval.

    With Carbon Window

  • Charge a depot fleet when the grid is cleanest

    Depot Charging pairs each vehicle's departure time and state of charge with the overnight forecast, then proposes charge windows that meet departures at the lowest marginal rate.

    With Depot Charging

  • Set a battery schedule on price and emissions

    Battery Dispatch reads the forecast beside day-ahead prices and proposes a charge and discharge plan that records the emissions estimate behind each hour.

    With Battery Dispatch

Requirements

  • A WattTime account. The Basic plan is free and covers the signal index in all regions plus every endpoint for CAISO_NORTH
  • An Analyst or Pro subscription for /v3/historical, /v3/forecast, and /v3/maps in regions other than CAISO_NORTH
  • A latitude and longitude for each site, or its region abbreviation, re-resolved at least monthly because region boundaries change
Authentication
A WattTime account created with /register; /login exchanges the username and password for a bearer token that expires after 30 minutes.

Limits

  • 3,000 requests per rolling 5 minutes per user, and 100 per 5 minutes on /login; excess returns HTTP 429
  • Each /v3/historical query covers at most 32 days; publishing delay ranges from under a minute to a few hours by region
  • Published values can be revised later, and model retrains or new model dates change the values returned
  • Reference listing: Fibric builds this integration for a managed deployment on request, and your WattTime plan sets which regions it can read

Access and pricing

Reference listing. Public feed access is separate from Fibric integration. If you request this feed, your quote covers the build, usage, and support.

Request WattTime Data API ↗

Questions and answers

Which WattTime data is free?
The Basic plan is free. It returns the 0-100 signal index from /v3/signal-index for every covered region, and every endpoint and signal for the CAISO_NORTH region. Historical, forecast, and map data for other regions need an Analyst or Pro subscription.
How often do values update?
The documentation describes periodic updates, at 5-minute frequency in its example, with each value valid for the period given in data_point_period_seconds. Forecasts are regenerated on the same schedule and cover a rolling 72-hour horizon.
What is the difference between co2_moer and co2_aoer?
co2_moer is the marginal operating emissions rate: the change in emissions caused by a change in load or generation. co2_aoer is the average rate of all generators running at that time, weighted by their output. Both are in lbs CO2 per MWh.
Ask about WattTime Data API

Ask about the capabilities and requirements in this listing.

For project-specific requirements, contact Fibric.

This Commons signal listing is developed, published, and supported by Fibric. It reads public data published by WattTime (api.watttime.org). Upstream agencies and projects are the property of their respective owners, who are not affiliated with Fibric and do not sponsor or endorse this listing. Trademark policy