The Carbon Intensity extractor pulls data from the Official Carbon Emissions Intensity API for Great Britain, which was developed by the National Grid. It is an interesting data source for playing with Meltano's analytical tools before you start connecting your own sources.
From within your Meltano account, navigate to the Pipelines tab in the top navigation and select Extract: https://meltano.meltanodata.com/pipeline/extract/
Select "Configure" to install the Extractor. Because it is an open API, no credentials are required and you will be advanced to the next step in setting up your pipeline.
tap-carbon-emissions comes with your Meltano instance, and you can configure it from the UI or the command line.
meltano add extractor tap-carbon-intensity
If you are successful, you should see
Added and installed extractors 'tap-carbon-intensity' in your terminal.