Sustainable or Not? Impacts and Uncertainties of Low-Carbon Energy Technologies on Water

Water is a key element of our energy system. It represents a valuable renewable energy resource, which is converted to electricity in hydro-power plants to meet both baseload and peak demand thus assisting the regulation of our power system. Furthermore, water has an indirect but significant role in the energy system as it drives the turbines, as steam, and provides for the cooling necessary for the operation of coal, natural gas and nuclear power stations, which generate most of the electricity consumed by our society; and is vital for the development of biomass resources, which are used for power generation and as an alternative fuel for transport, as biofuels, albeit today at small quantities.

It is apparent that the anticipated increase in energy demand, mainly for electricity and transport fuels, both in developed and developing economies, will increase water use and consumption in energy applications. It is however frequently overlooked that the future energy technology mix will also have a profound effect on water needs. The pressing need to reduce the emissions of greenhouse gases, which mostly result from the burning of fossil fuels in the power generation and the transport sectors, is currently driving the development and deployment of new technologies with a largely reduced carbon footprint, with the aim to replace the current carbon-intensive energy technology mix in the medium to longer term. While, many of these low carbon technologies will not require water for their operation, such as wind and solar photrovoltaic systems, others will require significant water quantities, such as carbon capture and storage and concentrating solar power technologies. In addition, new pumped hydro-plants need to be constructed to offer large scale electricity storage, which is essential for the large scale deployment of wind and solar intermittent energy sources; and the utilization of biofuels is expected to increase as a response to the need to decarbonise the transport sector. Therefore, the future need for water resources for the energy sector will be determined by the degree of increase of energy consumption by our society and the deployed mix of low carbon energy technologies.

This presentation will attempt to assess the needs for water in the European energy system in the medium to long term. Initially, the water consumption for key low carbon energy technologies, such as carbon capture and storage, biomass and biofuels, and concentrating solar power will be identified and will be compared to that for conventional energy technologies deployed on large scale today. Based on this information and on published scenarios for the evolution of the European energy system to 2030, calculations will be presented that assess the needs for water in the power generation and transport sectors and compare them with figures reflecting current consumption. Finally, the areas where low carbon technologies could improve to reduce water needs, whilst maintaining their techno-economic performance characteristics, will be identified.