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Adrian Hightower

The Water Energy Nexus: Generating Electricity Requires Clean Water. Cleaning Water Requires Electricity

Modern societies are built upon the assumption of access to both clean water and energy. Both water and energy are derived from natural resources. Human utilization of water and energy directly impact the environment on a global scale. The transportation and treatment of clean water requires significant amounts of energy. The California Energy Commission estimates that 20% of California’s electricity demand and over 30% of California’s natural gas demand are associated with water use. Energy resource extraction, production, transportation, storage and conversion all require copious amount of water. The Virginia Water Resources Research Center, Blacksburg, Va, estimates generating electricity by thermoelectric power plants in the United States alone requires on the order of 500 billion liters of water per day. Resource waste and environmental degradation can be mitigated by understanding feedback relationships of water and energy utilization and management.

Questions generated by Prof. Hightower’s Presentation

  1. What approaches are there for reducing water use in energy production?
  2. Is it possible to purify water by heating up dirty water in the power plant? That is, could we cool a power plant with dirty water and then pass the hot water on to a treatment plant?
  3. What are the costs of starting up and shutting down a power generating process?
  4. How does slurry transport of coal work? What are the environmental effects of this, and what happens to the water used?
  5. Dr. Hightower suggested that we could use hydroelectric systems to fill in for solar generation at night. Is our hydroelectric generating capacity really large enough for this?
  6. Does using cooling towers (instead of heat exchange with water from a nearby body of water) come with a thermodynamic efficiency cost because of a higher temperature of the cooling fluid?
  7. It seems that it should make a difference whether a process just transfers heat to or from water or whether it consumes water in a chemical reaction.
  8. Dr. Hightower mentioned environmental problems associated with a power plant using seawater as a heat sink. Does the release of waste heat from power plants in general cause environmental problems? Would this be mitigated through the use of distributed energy systems?
  9. In one of the first graphs the amount of hydro was expected to increase by 3--6x. Where are these rivers?
  10. Is there any way to use power plant waste heat to heat houses/offices?
  11. Is the number of people with inadequate water supplies growing?
  12. Are there ways to extract energy without using such huge amounts of water? Is there much research on this?
  13. Looking at the water consumption table, can we really consider the water used in biodiesel as consumed, since it will eventually get regenerated into the atmosphere?
  14. What does it mean to not have access to clean water? Is it a source of water that needs to be boiled?
  15. I thought the uncertainty in cloud cover feedback effects is pretty controversial.
  16. Is it really reasonable that we will run out of water or is this a question of efficiency?
  17. For nuclear energy is there anything more efficient than water?
  18. What effect does the use of seawater have on power plants? Is it equivalent to fresh water when used as a cooling source?
  19. Have there been any attempts to remove energy generation away from the Carnot engine idea?
  20. Is water scarcity one of the big reasons California is trying to push so much sustainable energy into use?
  21. How long does it take to rev-up peak loading plants?