Water use in a sustainable net zero energy system: what are the implications of employing bioenergy with carbon capture and storage?

Net zero emissions of the global energy and land systems are needed to keep the temperature increase to the 1.5 degrees limit by 2100 as per the Paris Agreement (PA). Furthermore, updated Nationally Determined Contributions (NDCs) now include a net zero target by 2050 or until 2070. These climate policies require rapid technological development towards renewable energy and low carbon emission technologies like nuclear and carbon capture and storage. However, this transition is water intensive as water is needed in power plants cooling, gasification, carbon capture, hydroelectricity, or emission control. In this study, the focus is done on the first three by using an integrated assessment model TIAM-FR. It is based on techno-economic linear optimization and includes a water allocation module. Under two climate scenarios, the energy mixes of the world energy system are scrutinized. The results show that achieving net zero requires renewable energy mainly but would use bioenergy with carbon capture and storage. For the 2018-2100 period, water consumption increases by 100.5% for a 1.5-degree pathway whereas an NDC pathway increases it by 135%. The comparative analysis asses the choice of mitigation solutions with respect to regional water scarcity. At the end, a discussion on the relevant sustainable development goals (2, 6, 7, 13, 15) is presented.