The Scattergood power plant in El Segundo, CA, is owned by the Los Angeles Department of Water and Power and utilizes OTC. Image: California Coastal Records Project
The El Segundo power plant, located just south of the Scattergood plant, also uses the outdated OTC process. Image: California Coastal Records Project

What is not as well-known is that a large number of existing power plants located along California’s coast also contribute directly to the degradation of the state’s marine environment.

Alarmingly, twenty-one of California’s coastal power plants utilize outdated once-through cooling technology (OTC), in which intake pipes, drawing in millions of gallons of ocean water daily to cool the plant, kill plankton, fish, invertebrates, and other marine life. Then, the heated water is released back into the fragile ocean environment. Together, California’s coastal power plants that utilize OTC are permitted to draw in nearly 17 billion gallons of sea water per day.

Impingement occurs when fish, marine mammals and other marine creatures are pinned by the suction against screens located on intake pipes, which often kills them. Entrainment is the process by which small organisms, larvae, and eggs are sucked through the intake screens into the plant where they are killed by the heat and pressure within the cooling system.

Coastal power plants utilizing OTC also impact coastal ecosystems by releasing heated water back into the ocean, thus potentially upsetting the surrounding ecosystem by raising the water temperature to damaging levels.

In a related issue, co-location of proposed desalination plants has the potential to prolong the use of OTC power plants further exacerbating environmental damage.

Larger Environmental Impacts
The larger impacts of once-through cooling are considerable. For instance, the indiscriminate take of plankton, fish, invertebrates, and other marine life may alter and stress marine and estuarine food chains; decrease diversity; deplete commercially and recreationally important species; alter ecosystem structure and function; and cause further threat to species at risk of endangerment.

Although the impact of individual power plants on local coastal marine ecosystems is significant, the cumulative impacts from closely located facilities are likely even more damaging. In Santa Monica Bay, three power plants – Scattergood, El Segundo, and Redondo Beach Generating Stations – are located very close together at the southern end. Together, these three facilities withdraw and recycle 13% of nearshore waters in the Bay every six weeks.

Given that our local coastal waters are also highly impacted by other uses, including fishing, sewage treatment plant discharges and stormwater runoff, the impacts of this outdated cooling technology may serve to exacerbate the environmental problems within the already stressed Santa Monica Bay.

Federal & State Regulations
In 2004, the United States Environmental Protection Agency issued regulations requiring existing power plants using once-through cooling to reduce their environmental impacts by establishing performance standards to reduce impingement and entrainment at these facilities. Unfortunately, these regulations contain many potential loopholes that could allow facilities to avoid meeting the performance standards. California is currently developing a policy on how to implement the new once-through cooling regulations in the state.

What Heal the Bay is Doing
Heal the Bay is closely following this statewide regulation process, and is advocating for a protective California policy that does not include the flawed loopholes found in the federal regulations.

Heal the Bay also is actively tracking the permitting process for coastal power plants in our region and encouraging implementation of the most environmentally protective alternatives to once-through cooling. Methods to reduce impingement and entrainment include operational and technological changes, recirculating cooling, dry cooling, and the use of alternative cooling water sources, such as wastewater.

In addition, we strongly support cooling alternatives that eliminate impingement and entrainment altogether, such as dry cooling and the use of alternative cooling water sources to comply with the new regulations.