Calculations details are here: https://github.com/tmrowco/electricitymap#carbon-intensity-c... We use IPCC LCA data for the production mix, and use a coupled linear system of equations to take into account imports in a dynamic manner.

Generation data is realtime and comes from ENTSOE (https://transparency.entsoe.eu)

Very cool.

I'm using UK-specific carbon intensity values, and breaking down different uses of the same fuel (OCGT & CCGT). I've not baked in transmission loss yet. Our results are surprisingly similar though.

Feel free to submit a pull request to update our numbers!