The $1 billion Carlsbad Desalination Plant officially opens Monday and starts producing 50 million gallons of drinking water a day. That’s enough water to fill an Olympic-size swimming pool every 18 minutes.
The project was in various phases of planning and construction for two decades.
The facility is built on about 6 acres of land next to the Encina Power Station beside the Agua Hedionda Lagoon.
Bob Yamada is the director of water resources for the San Diego County Water Authority. He answered five questions about the desalination project.
What is desalination?
Yamada: Desalination, as it's being applied to the Carlsbad project, means taking in seawater and cleaning that seawater up and running it through a process called reverse osmosis that essentially separates the fresh water from the salts. And by doing so, we can create drinking water out of ocean water, which, as we all know, is not drinkable.
Why is it important to develop local water supplies?
Yamada: It is very important that we develop not only new supplies of water but also new local supplies that are locally controlled. And a supply that is drought-proof like the Carlsbad desalination project is. Back in the early ’90s when this region was facing 50 percent cutbacks in its water supply — coming out of that, the charge was, we need to diversify our water supply, we need to strengthen that reliability. We did so by many means, including the agriculture urban water transfer (moving water from the Imperial Valley to San Diego) we have, and including developing recycled water supplies and additional groundwater desalination. And now we’re adding a significant new water supply in seawater desalination to that portfolio that replaces unreliable imported water supplies.
Where does San Diego’s water come from?
Yamada: The San Diego region gets about 64 percent of our water from the Colorado River, about 20 percent from the state water project in Northern California, with about 16 percent in local supplies. With the addition of the Carlsbad desalination project, that local supply will grow to 25 (percent) to 26 percent. So it’s a substantial increase in the percentage of our water supply that’s served by local supplies.
Why is this water so expensive?
Yamada: The Carlsbad desalination project is actually a public-private partnership, whereby the water authority as the regional water wholesaler is purchasing the water that’s produced from the Carlsbad project and Poseidon Water. That is the owner of that project. The water authority has committed over a 30-year period to purchase the output from that project at a set rate, and that rate will escalate over time. We expect the cost of water to approach the cost of imported water as we go out into the future. Ultimately, we think the water from the Carlsbad project will be less expensive than our current imported water supply. Right now, the cost of imported water is about half of what the cost of water from the Carlsbad plant.
How much will the typical resident pay?
Yamada: Whether you’re going to directly receive water from the Carlsbad plant or you may not get that water directly, you are receiving the reliable benefit of having that water supply as part of our overall water supply portfolio. The average ratepayer in San Diego is going to see an average increase of about $5 (per month) to pay for the Carlsbad project over time.
