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US EPA Clean Water Act 316(b) Phase 2 Regulations on
Cooling Water Intakes:
Cooling Water Intakes:
- The US Environmental Protection Agency (EPA) Clean Water Act 316(b) rule sets standards on
cooling water intake structures of coastal power plants.
Along the coast of California, all the coastal power plants combined are allowed to suck in 16.7
BILLION gallons per day for their Once-Through Cooling (OTC) systems. OTC is one of the cooling
technologies power plants could use. This method sucks in rivers of ocean water and circulates it
through the plant only once before discharging it back into the ocean at a high temperature. This
method of cooling is cheap because the power companies do not have to pay for the water, unlike
the cost of construction and maintenance of alternative technologies. Not only does this increase
the ocean temperature near the discharge and have a negative affect on marine life, but the intake
pipeline entrains (sucks up small marine organisms that do not get filtered out) and impinges
(larger marine animals get sucked against filters due to high velocity of intake) marine life as well.
Phase 1 of the CWA 316(b) regulations addresses the intake structures on new power plants,
while Phase 2 addresses the intake structures on existing power plants. This law requires that the
best technology available is used to minimize impacts on marine life and sets impingement and
entrainment standards, requiring that they be reduced by 80-95% and 60-90% respectively.
- In order to meet these standards, alternative cooling technologies must be used instead of OTC.
Alternative technologies available are dry cooling, closed-cycle wet cooling, or hybrid cooling
systems. For more information, go to the US EPA's website on the 316(b) regulations.
What is going on right now and how does this relate to Desal proposals?
- If these regulations are enforced, existing coastal power plants will have to use new technology that
minimizes the impacts on marine life. In all cases, OTC with ocean water will have to stop
because there is no other way to meet these standards than to completely stop open water ocean
intakes. If this happens, the source water for the desal plants will no longer be available and the
desal plants will be unable to produce water.
Co-located ocean desal plant proposals provide a new use for these outdated power plant cooling
systems. Even though desal plants at this point are a speculative source of drinking water, power
plant operators will use desal to get exemptions from these standards.
