Technologies for utilization of industrial excess heat: Potentials for energy recovery and CO2 emission reduction

Industrial excess heat is a large untapped resource, for which there is potential for external use, whichwould create benefits for industry and society. Use of excess heat can provide a way to reduce the useof primary energy and to contribute to global CO2 mitigation. The aim of this paper is to present differentmeasures for the recovery and utilization of industrial excess heat and to investigate how the developmentof the future energy market can affect which heat utilization measure would contribute the mostto global CO2 emissions mitigation. Excess heat recovery is put into a context by applying some of theexcess heat recovery measures to the untapped excess heat potential in Gävleborg County in Sweden.Two different cases for excess heat recovery are studied: heat delivery to a district heating system andheat-driven electricity generation. To investigate the impact of excess heat recovery on global CO2 emissions,six consistent future energy market scenarios were used. Approximately 0.8 TWh/year of industrialexcess heat in Gävleborg County is not used today. The results show that with the proposed recoverymeasures approximately 91 GWh/year of district heating, or 25 GWh/year of electricity, could be suppliedfrom this heat. Electricity generation would result in reduced global CO2 emissions in all of the analyzedscenarios, while heat delivery to a DH system based on combined heat and power production frombiomass would result in increased global CO2 emissions when the CO2 emission charge is low.