In the UK, a storage heater earns a "Poor" rating for Environmental Performance on an Energy Performance Certificate. However many progressive countries are developing their electricity generating system, principally, to incorporate "greener", more sustainable and renewable energy sources; so how "green" a storage heater system is would in principle depend on how the electricity used is generated. Of course this argument applies to all forms of electric heating, but the ability of a storage heater system to use electricity at times when, for example, wind generated electricity could not otherwise be used, may in conjunction with a smart grid give storage heating a new role in the future.