Good afternoon Lawrence. Apologies for the slight delay in replying to you, we are very busy at the moment! Green energy tariffs are something I have never been asked about before, but having done a little bit of research (http://news.bbc.co.uk/1/hi/business/7511683.stm)i have discovered that they are somewhat confusing. My advice to you would be to stick with your standard energy tariffs and if you feel strongly about offsetting, put your money into a recognised scheme that you trust such as http://www.climatecare.org/.As far as renewables go, this would certainly reduce the amount of energy you would take from the grid but the initial set up costs can be quite high and payback can be long. If you would like to email me with your details at enquiries@eviee.co.uk i will have one of our roofing team call you to discuss any solar project you may wish to undertake.