They do not work everywhere.

I did a test for mine. Take heating for example. Our average heating usage makes us quite high.

BUT we have "town heating" which is heating piped from the heat exchangers on the local power station. Which other wise would end up in the canal, or drifting into space.

Also, the power station is fired by pellets made from the parts of the rubbish collection which can not be otherwise recycled.

So although our heating foot print is high, the method of creation should give us a LOWER score.