Here is NPower's explaination. They were trying to correct an error in the government calculations for reduced UK carbon emmisions :-0
Good afternoon Mr Payne,
Thanks for your email.
Earlier in the year all European countries published figures for reductions in the amount of carbon dioxide (CO2) emitted from power stations. However, the UK Government miscalculated its figures for the basis of these reductions. As a result npower, together with other energy businesses, decided to initiate legal action against the European Commission to get approval for this major error to be corrected.
Although Greenpeace understands our position, they are completely opposed to any increase in the level of CO2 emissions. On this fundamental point of principle we have been unable to find common ground and, as a result, the formal relationship between us will end in August.
Although Greenpeace will no longer formally endorse Juice, they will be happy to recommend it as the best non-premium green electricity product.
Trust this has answered your query.
tel: 0845 166 3443