Decarbonising the Heat: What 55 European City Case Studies Reveal About Fossil Fuel Phase-Out in Buildings

Buildings account for about 40% of final energy use in Europe, yet heat decarbonisation rarely gets the global attention it deserves. This session draws on the EU Covenant of Mayors' Cities Heat Detox campaingn, 55 case studies across 22 EU countries (2024–2025), to present one of the most compriehensive evidence sets on city-led fossil fuel phase-out in buildings.

Cases range from Vienna's city-wide gas phase-out (eu-mayors.ec.europa.eu/en/vienna-s-heat-detox-for-an-even-happier-city), to Warsaw's waste-heat recovery from metro infrastructure, to Mechelen's multi-stakeholder Heat Coalition, to Marseille's seawater-based district cooling. The sessison extracts transferable design principles: when does district heating work versus building-level solutions? What financing models scale? How does citizen engagement shape outcomes?

The evidence base spans cities of all sizes, from large capitals to small towns, explicitly addressing the financing and governance barriers that affect less-resourced municipalities most. Energy poverty and affordability are treated as primary design considerations throughout.