1.6 Carbon Aware Design

Website uses “carbon aware design”.

Hard to implement
8
High impact score

Examples 

Both websites know the emissions factor of the grid the person using the site is on, and as a result changes colours, image resolutions, image appearance (consider dithering like Waste Not) and logos, depending on whether the grid is being mainly powered by renewable energy or fossil fuels. 

Lookups such Electricity Maps or the Green Software Foundation SDK can be used. 

By implementing these techniques, you also need to consider what caching strategy you apply and how this will be affected.