The WattTime integrationIntegrations connect and integrate Home Assistant with your devices, services, and more. [Learn more] allows users to get real-time emissions data for a latitude/longitude from WattTime.

Registering an account

WattTime account registration is accomplished via the REST API itself. The simplest way to do this is by using cURL on the command line:

curl -X "POST" "https://api2.watttime.org/v2/register" \
     -H 'Content-Type: application/json' \
     -d '{
       "username": "<USERNAME>",
       "password": "<PASSWORD>",
       "email": "<EMAIL>",
       "org": "<ORG>"

Note that the org value can be anything you like – it doesn’t need to represent a real entity.


To add the WattTime integration to your Home Assistant instance, use this My button:


The sensors available to you will depend on the type of WattTime subscription you have. You can reach out to WattTime to upgrade your subscription via [their website](https://www.watttime.org/contact/).
Name Subscription Level Meaning
Marginal Operating Emissions Rate Pro The currently measured amount of lbs of CO2 per MWh
Relative Marginal Emissions Intensity All A percentage between the lowest (cleanest) and highest (highest) MOER values observed in the past two weeks

You can learn more about the data that WattTime collects by viewing these articles: