CARBON MITIGATION IN THE POWER SECTOR AS A SOLUTION TO GLOBAL CLIMATE CHANGE, A GOOD IDEA BUT HOW MUCH WATER WILL It COST?

Issues of water unsustainability with respect to future energy projections are discussed in order to enhance our understanding of the feedback loop between water and energy and explore potential approaches to meet future energy needs without compromising water resources. Energy projections to 2050 from the International Energy Agency (IEA) are compiled, modified, and then used to model-calculate operational water requirements for electric-power generation. Water withdrawal statistics from the U.S. Geological Survey are used as model validation. Results show that the water needed for power generation in 2050 is expected to be much greater than current (2007) demands, whether in a carbon mitigating energy setting (average global increase of operational water withdrawal of 107%) due to the use of carbon capture and storage (CCS) technology, or a setting where energy policy remains “business-as-usual” (average global increases of 158%) because of the high water demand of thermoelectric power plants. In order to determine what future action would be most beneficial, a sensitivity analysis is performed to examine what factors of power generation have the greatest potential to alter future water needs. Analysis indicates that if a global average of 77.7% of coal, natural gas, and biomass power plants are equipped with CCS by 2050 (following IEA’s future projection), then operational water withdrawal and consumption will respectively be 66% and 32% greater than in an equivalent energy scenario without CCS. The sensitivity analysis also shows that the most effective (and feasible) potential methods to combat these future increases in water needs from CCS are through the implementation (or modified use) of four fundamental factors of power generation. These include (1) the use of closed-loop cooling towers and not open-loop cooling at thermoelectric power plants, (2) the use of combined cycle technology at all coal and natural gas power plants, especially those being installed with CCS technology, (3) the implementation of as much renewable energy (wind, solar photovoltaic, and ocean energy) as allowed for by other resources, and (4) the conservation of energy.