Electricity Maps isn't the only provider of information like this, but they do seem to offer the broadest global coverage.

I found out recently that in Germany, one of the major grid operators is exposing realtime information over an API too, without charging.

You can see the map version below:
https://co2map.the-nest.io

And the API docs are here:
https://portal.traxes.io/co2intensity-dev/documentation/co2itensity

Add CO2 Signal API to CO2.js

Add Electricity Maps API to CO2.js

There is now an API for Germany (or at least the northern part of Germany covered by the 50hz grid)

https://eco2grid.50hertz.com/calculation

API details below:

https://api-portal.eco2grid.com/

After chatting with @rossf7 about this, based on his experience with thegreenwebfoundation/grid-intensity-go I'd like to make this a more modular approach.

This would separate the code logic for using an external data source from the CO2 calculation. In this way, we would also make it easier for folks to contribute other data sources (like the Germany one @mrchrisadams linked to above).

In this way developers can also use CO2.js as a means of connecting with an external data source, even if they don't want to use that data for a carbon calculations.

To make this possible, we'd have to create a new Class, which we can then expose to users. This can then be imported into a project.

Being worked on in https://github.com/thegreenwebfoundation/co2.js/tree/add-external-data-sources

Should have a PR ready for review in the next couple of days.

This would also present an opportunity to:

1. Build this in a way that supports a plugin architecture (similar to what's outlined in Switch to a plugin style approach to exposing models in CO2.js #206)
2. Write this part of the library in TypeScript, so that we can start to move CO2.js towards using TypeScript incrementally.