Impacts of flexible-cooling and waste-heat recovery from data centres on energy systems: A Danish case study

The fast development of large data centres increases energy demand, pressuring energy systems and potentially hindering progress towards climate targets. Nevertheless, data centres are also a potential sector-coupling interface supporting the energy transition through demand flexibility in electricity markets and waste-heat recovery for district heating systems. In this respect, this paper quantifies the economic and environmental benefits of integrating large data centres into highly renewable energy systems, using Denmark as a case study and focusing on the transition until 2035. The Balmorel energy system model optimises the investments and operation of the energy system along with the data centre's portfolio of flexible-cooling and waste-heat equipment. The results illustrate that waste-heat recovery displaces conventional heat pumps in district heating, indirectly reducing investments in photovoltaic capacity while increasing electricity exports. Integration reduces Danish energy system costs by 5.1% and carbon emissions by 1.4% throughout this period. More importantly, this study highlights the significance of optimal integration, which saves up to 63% of costs and 180% of emissions that non-integrated data centres would otherwise incur. While these figures depend on local conditions, they emphasise the high costs to society of non-integration and the need for appropriate policies to support such integration.