Desalination plant gets green light. Will energy use spike water rates?
The Santa Cruz City Council has unanimously endorsed an agreement for a desalination plant, sparking community concerns about energy and environmental impacts.
Their March 23 decision gave the green light for project design and planning, but does not commit the city to construct the plant, says Mayor Mike Rotkin. The agreement also outlines a water-sharing plan with the Soquel Creek Water District, giving Santa Cruz primary rights to use the facility.
“The city council is on record at this point for moving forward with the desalination plant, although we won’t approve construction until we have seen the environmental review,” says Rotkin.
The decision trails a March 9 vote to renew a $300,000 contract with Kennedy Jenks—a San Francisco-based environmental firm charged with soliciting plant designs. A request for designs proposals will be sent out in April. “This is an optimistic prediction, but if all goes smoothly, the desalination facility could be running by 2015,” says Rotkin.
The plant will remove five million gallons of seawater from the Monterey Bay each day—possibly through vents built into the sea floor. Reverse osmosis will produce 2.5 million gallons of drinkable water. The remaining brine will be trucked to a water plant, mixed with treated wastewater, and put back to the bay.
Community members met on March 18 to discuss concerns over water rate hikes, and the plant’s energy use. Held at the Live Oak Elementary School, response was largely negative. Of the 220 attendees, 110 responded to an opinion poll. Only 18 participants said they wanted to see the plant built.
“The desalination plant will use a lot of traditional energy, which only contributes to the problem of global climate change,” says David Stearns, who attended the workshop and helped organize speaker panels.
In Mediterranean climates like Santa Cruz, global warming is predicted to lengthen the dry season, and cause unpredictable weather patterns. “We won’t solve this problem with desalination because it releases more greenhouse gasses than any other option,” says Stearns. “Desalination will exacerbate climate change, and leave us more dependent on the power grid during a time when energy prices will be highly volatile.”
Past plant designs underestimated the cost of energy use by 32 percent, according to a report published in March by the statewide nonprofit Residents for Responsible Desalination.
Energy use accounts for more than half the cost of desalinating water. Efficient desalination takes 12.5 kilowatt hours to produce 1,000 gallons of purified seawater, says Linette Almond, deputy water director and engineering manager or the Santa Cruz Water Department. In contrast, it takes three-kilowatt hours to treat 1,000 gallons of river water.
The city has not yet released how much of the plant’s power will be offset by renewable energy. Rotkin says solar panels will likely be placed on city buildings, making Santa Cruz greener over all. While the panels will not directly supply energy to the plant, they will help compensate for the increased energy use.
Stearns says the city should account for its current footprint before introducing more demand for energy. “Putting up solar is a good place to start, but panels on city buildings really need to address current energy use,” says Stearns. “Unless they build enough solar and renewable energy sources to directly run operations, the city will be using a lot more energy, and consumers will eat the cost in the form of water rate increases.”
Rotkin says he can’t predict how much rates will rise in Santa Cruz, but says the cost of the desalination plant will result in an increase. “There are no final cost figures yet, but it will definitely come out of rate increases and water system hook up charges,” he says.
Israeli communities raised water rates by as much as 36 percent after introducing desalination, according to the Israel National News. In California, desalination costs $3,000 to $13,000 per acre-foot. “It won’t likely be any cheaper than $4,000 for Santa Cruz because the city is building a small plant,” says Debbie Cook, a current board member at the Santa Rosa-based Post Carbon Institute, and a speaker at the March 18 community forum. In contrast, drawing water from surface sources and aquifers may cost about a few hundred per acre-foot.
In the United States, electricity prices are predicted to rise over the short term as renewable power sources like wind and solar slowly integrate into the grid. “The feedback loop will kill desalination in Santa Cruz,” says Cook. “The increase in rates forces people to conserve water whether they want to or not, or else they find a way to get water from somewhere else. This kills the demand for the plant.”
A similar case unfolded in Santa Barbara, Calif., 10 years ago. In 1991 voters approved a $34 million desalination plant, but due to a lack of use, the City of Santa Barbara sold half of the plant’s modules in 2000. “They never incorporated the plant into the city’s water supply.” Says Cook, “It’s in standby now, but not operating.”
If approved, the Santa Cruz desalination plant will be one of the first city-backed plants of its kind. Catalina Island is home to the only desalination plant designated for public utility. Carlsbad, Calif. recently approved a public plant, but must still clear several permitting issues. Statewide, about 19 ocean desalination plants have been proposed.
“If cities shift towards desalination, and all these go online, the climate impacts will be very large,” says Cook.
Environmental impact review processes don’t currently evaluate climate costs. There is no rule in place that allows agencies to deny permits based on greenhouse gas emissions.
However, Rotkin says the plant will help Santa Cruz survive a bad drought cycle. “We have done the easy things like drip irrigation and low flush toilets,” he says. “We looked at the possibility of saving 10, 15 and 30 percent of our water, and after a lot of discussion we decided 15 percent is the amount we could curtail use. Even with this level of conservation, we will still need the plant during a bad series of drought years.”
Cook says there is room for improvement. In Australia consumers use less than 35 gallons a day. The average Santa Cruz resident currently use about 66 gallons of water a day. “Elected officials are always reluctant to tell people to use less of something,” says Cook, who served as the mayor of Huntington Beach in 2002 and 2008. “People don’t like it, but it can and has to be done.”
Installing rooftop harvesting on UC Santa Cruz and city buildings could capture winter rains, providing water for the first few months of the summer. Gray water is now a legal option for homeowners, and many cities are exploring incentive programs.
While the city and university have installed water-saving fixtures and successfully cut water demands, there is no discussion of gray water or rooftop capture. “This might be something to look into,” says Rotkin.
Santa Cruz is expected to grow by 11,000 people by 2030. This number includes 4,000 additional students predicted to enroll at UCSC during its expansion. In total, 374 acres of forest will be disrupted for new buildings, including many second growth redwoods.
“Redwoods are among the best in the world at sequestering carbon,” says Stearns, “whether or not we need the desalination plant due to university expansion, it’s ironic the city is losing so many acres of valuable offset resources all while building one of most climate-damaging sources of water.”
Debate over the plant’s necessity, cost and environmental impact will intensify over the next three months. Three studies will be released in April and May, including a yearlong trial project detailing the results of a small-scale plant constructed at the Long Marine Lab in 2008. An energy minimization and greenhouse gas reduction report are also being finalized, according to water district officials.