Via the Environmental Research Web, an interesting report on the watergy consumption of power plants:
US power plants – in particular their cooling systems – are responsible for more than 40% of the nation’s freshwater consumption. However estimates of how much water is used at individual power plants can vary greatly. What is more, most long-term projection models for power-plant water use lack sufficient data when it comes to different regions of the country.
The development and construction of future power plants will depend, in part, on water availability in a particular region. Understanding how much water is used in different types of plants, be they coal, nuclear or based on renewable sources, will thus be crucial for developers and policymakers alike.
We collected published water-use data from academic literature, state and federal government agencies, non-governmental organizations and industry. We converted these data into a consistent metric of gallons of water use per Megawatt-hour (MWh) of electricity generated. This approach allowed us to provide estimates of the amount of water consumed for each type of electricity-generating technology and cooling system.
Our results show that certain low-carbon electricity technologies using recirculating cooling systems, such as concentrating solar power, coal with carbon capture and storage, and nuclear power, can consume more water than conventional technologies like subcritical pulverized coal and natural-gas combined-cycle technologies.
Other low-carbon technologies, like solar photovoltaic and wind, require little to no water to generate electricity.
Dry cooling technologies, which can work for concentrating solar power, geothermal, natural gas, biopower and power from coal, can reduce the amount of water consumed by as much as 90% compared to recirculating cooling technologies. However, these technologies, while reducing overall water usage, might also be less efficient.
The fact that different technologies – such as concentrating solar power, nuclear, coal and geothermal – show large variations in water consumption means that future analyses could yield disparate results if average water consumption values are used in calculations. We are thus currently looking at ways to “standardize” the assumptions behind estimates of water use to reduce such data variability.
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