Election2015 policy low carbon Labour CHP heat metering energy bills project district heating pipe district heat awards conference DECC better energy Building assessment micro chp district heating potential energy demand district heating Boris Johnson electricity capacity heat billing landlords locale energy advice consultation Electricity Surge biomass Rehau energy efficiency Demand Side Response Party Manifestos government blogs London market combined heat and power substations green deal World Cup consumer international Energy Policy local authority heat networks industrial gas supply National Grid community energy europe heat networks small scale tax Russia renewables Reducing Electricity Demand data collection guidance district heating history businesses Building regulation heat networks delivery unit UK Conservative heat energy users efficient energy security of supply local efficiency Birdsill Holly BREEAM