VOICES | LARS FABRICIUS The sharing economy Using heat networks to share waste heat and store surplus renewable energy will take pressure off the Grid and offer the UK a cost-effective route to net zero, says SAV Systems Lars Fabricius T he UKs energy sector has made great progress in reducing carbon emissions with the growth in renewable energy. Wind power, in particular, has been so successful in replacing fossil fuels that Grid integration is now becoming the real challenge. As a result of a shortfall in transmission capability, it is estimated that the UK exploits only around 50% of its installed wind-power capacity. The consequence of this is that, to balance the Grid in 2019, the Balancing Services Use of System payment was more than 1.4bn, which includes constraint payments to wind farms for discarding power. Using large volumes of wind-generated electrical power makes balancing the Grid difficult. To improve the situation, huge investments in grid infrastructure are required, alongside modulating conventional, controllable power plants. This includes demandresponse initiatives, electricity import and export through transnational interconnectors, and electricity storage, such as hydroelectric and batteries. LARS FABRICIUS is managing director at SAV Systems Import This illustrates the inflexibility of this solution, and highlights the need for alternative approaches to storing energy, such as power to heat and power to gas. By contrast, in Denmark which has probably the highest percentage of wind power per capita in the world there is a growing appreciation that successfully replacing fossil fuels with renewables will require far more than wind turbines and batteries. It will require a complete revolution of the countrys economy. Denmark turned to renewables as a reaction to the oil crisis in the early 1970s, when most Danish homes had oil-fired heating. The drivers for change were cost and security of energy supply; now, a target of net zero by 2050 is driving Denmark to embark on a second renewables revolution. The expensive hard electric approach being pursued by the UK has been eschewed in Denmark in favour of sector (or utility) coupling to provide low carbon heating and cooling to buildings. This is based on installing heat networks in urban areas to share energy between sectors, with heat pumps used to supply heat to 4.8TWh 4.8TWh 5.0TWh 21.9TWh Wind Hydroelectric power, wave power 79TWh Electricity 1.3TWh Photovoltaic 12.2TWh Solar thermal 4.5TWh 6TWh Electric heating 7.2TWh 2.4TWh Heat pumps & elec heating 7.5TWh 2.1TWh 8.5TWh 15.1TWh Cooling Individual consumption 9.7TWh 35.6TWh Heating network 1.0TWh 1.1TWh Biomass waste 3.8TWh 12.7TWh 7.5TWh Waste heat Losses and compulsory export Electricity consumption (domestic and services) 1.6TWh 0.5TWh Sun Geothermal Export 5.0TWh 42.5 TWh Figure 1: Sankey diagram showing how Denmark can achieve 100% enable energy supply by 2045, based on the Danish Society of Engineers (IDA) proposal (in collaboration with the Department of Planning at Aalborg University 7.7TWh 9.6TWh 16.5TWh 0.2TWh CHP & waste incineration 26.7TWh Conversion losses 15.1TWh 23TWh 1.2TWh 24.3 TWh Diagram courtesy of Aalborg University: Lund, H.et al (2021). IDAs Klimasvar 2045 Sdan bliver vi klimaneutrale. Ingenirforeningen IDA Transport 39.2 TWh Transport Conversion losses Biomass & gasication Conversion losses Losses 9.7TWh Gas: 2.3TWh Electricity: 0.7TWh 8.8TWh Biofuel conversion Conversion losses 3.4TWh 3.4TWh 20.9TWh Industry and data centres 27.7 TWh Industry and data centres 36 May 2022 www.cibsejournal.com CIBSE May 22 pp36-37 Lars Fabricius.indd 36 22/04/2022 18:09