Energy From Wastewater as a Renewable Energy Source for Heating and Cooling in Municipalities and Industry.

Successful Implementations, Further Potential and Future Outlook

Abstract

Energy from wastewater is increasingly recognized as a valuable, locally available renewable resource that can support the decarbonization of heating and cooling in both municipal and industrial sectors. This article highlights its diverse applications, including the supply of existing buildings, inhouse solutions, tapping treatment plant effluents, wastewater‑based cooling, and the benefits of digitalization for system monitoring and optimization. It also underscores the potential of combining wastewater heat with other renewable sources to enhance seasonal performance and system resilience. Recent real‑world projects demonstrate the technological maturity and reliability of wastewater‑based energy systems. Notable examples include the heating of the Town Hall in Tulln using approximately 100 kW of wastewater heat, and the large‑scale system at voestalpine in Linz, delivering 1 MW of heating to production areas and office spaces. Looking forward, the broader roll-out of energy from wastewater projects will depend on strengthened regional energy planning, standardized and accessible data, targeted funding schemes for feasibility studies and pilot projects, and closer collaboration between the wastewater and energy sectors. These advancements position wastewater as a key contributor to future climate‑neutral and resilient energy systems.