Analyzing possibilities of using energy from surface and sewage water for the energy transition of the built environment : study in the Netherlands

With the arrival of the Environmental act in the Netherlands, municipalities are getting more responsibility for the energy transition which demands eventual disposal of fossil fuel-based energy systems. As alternatives, the focus of this study is on thermal energy from waste and surface water. Even though some studies have already shown the national and local energy potential with waste and surface water, for a lot of local policymakers, the energy potential and how and where it can be applied in their community is unclear. This study explored the current methods of extraction, storage and distribution of thermal energy from waste and surface water and how and where it can be applied in a local region (Breda). A potency map was made showing the monthly heating/cooling demand. The potential supply energy is calculated by using monthly averaged flow rates and temperatures based on measured data. The results show that currently a theoretical maximum of 41% of the heating demand for residential buildings can be supplied with energy coming from river water (surface water), and in the future, when the houses are more energy efficient, this could be 69%. However, the surface water potential seems quite high, as at the moment the whole river is being used. In reality, this percentage will be a tenfold lesser as the intake pump or heat exchanger will only use a small part of the river. For wastewater, the energy supply is lower with a current value of 25% and a future value of 44%.