How are we going to de-carbonise heating of buildings?

1. How are we going to de-carbonise heating of buildings? Important question because building heating is the largest use of end use energy Two strategies considered in this presentation: • Now - Elec plus house heat pumps with ccgt , long term wind to electric to house heat pump, ccgt as back up and pumped hydro storage • Now - District Heat with ccgt as chp, long term wind to central heat pump to DH, ccgt chp as back up and thermal storage

2. Costs • The Elec route needs extra power cables since existing ones are not big enough if all houses in a city had electric heat pumps. Must be ASP but these don’t work well when it is cold • The DH route needs expensive DH mains to be laid. • Both need digging up the streets • Both need storage • Maybe insulation

3. Heat stores are an integral part of CHP and DH –20 times cheaper than elec storage per unit energy stored 6 hour store in Odense - Inter-seasonal have been designed

4. CHP is a heat pump, but with COP (Z) of 11.45 compared to HP with 2.8 if you’re lucky This Iron Diagram shows that Odense power station generates about 430 MW in electricity – only mode ( left axis) , and loses electrical output when 550 MW ( lower axis) of heat is produced as chp. Over the whole range, loss of 1 kWe of power creates 11.45 kWth of heat. A heat pump is much worse and only delivers about 3.2 kWth of heat, for the loss of 1 kWe of electricity over the year, down to 2.2 in winter

5. Chpdh can readily cope with intermittency: • Heat stores store and forward at a later time, surplus wind energy • CHP can coast at low load with any spinning reserve losses captured as useable heat • CHP can switch to elec only mode with instantaneous increase in power, and vice verse AND • CHPDH can utilise: solar, geothermal, industrial waste heat

6. Double today’s energy costs, 10 day storage, €4.5k of insulation gives a 1/3 reduction of heat energy, COPs 3.2, 2.2 and 2.

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