When the Carlsbad desalination plant opened in December 2015, regional water officials gushed about how reliable it would be. San Diego could now drink from the endless Pacific Ocean rather than be stuck depending on rain and snowmelt to come from hundreds of miles away.

So far, though, the plant has not been as reliable as promised.

Over the last year, the privately owned plant failed to deliver nearly a fifth of the water the San Diego County Water Authority ordered from it.

During the same period, there were 46 days when it delivered no water at all, according to business and regulatory filings by the plant’s owner, Poseidon Water.

Some of the shortfalls can be blamed on hiccups at a plant that is still getting its sea legs. The plant is the country’s largest ocean water desalination plant.

But, if anything, the plant’s reliability has gotten worse since it first opened. In 2016, Poseidon filled 95 percent of the Water Authority’s orders for water. So far in 2017, the company has only filled 70 percent of the Water Authority’s orders.

Reliability was the plant’s key selling point. Otherwise, it would be hard to justify the cost of its water. An acre foot of water from the plant costs $2,400. An acre foot is about as much water as two single-family homes use in a year. The Water Authority’s other major sources of water cost about half as much.

On Thursday, Poseidon CEO Carlos Riva met with the Water Authority’s board to reassure it that “these types of shortfalls are not unusual in large and complex projects” and that the company is adjusting.

“I want to assure you that Poseidon will continue to be a good steward of this important water supply asset for the community over the 30-year life of the project,” he said.

Water Authority officials also continue to speak highly of the 30-year deal they signed with Poseidon and of the company itself. They say ratepayers are insulated from financial risks – when the plant isn’t working, we don’t pay for it. There’s also so much water available after a wet winter that the plant’s water isn’t needed right now anyway. The issues at the plant have not affected the safety of people’s drinking water.

But, even as Riva spoke, the plant was down because of a mechanical failure that happened a week earlier. He said the plant would be back up and running “as soon as possible.”

The deal between the Water Authority and Poseidon is being closely watched around California. For one thing, besides the expense of the water, the Water Authority has to buy Poseidon water even when it doesn’t need it, which is one reason San Diego has some of the highest water rates in the country. Poseidon is also hoping to use the success of the Carlsbad plant to sell another one to water agencies in Orange County.

The San Diego County Water Authority promised to buy at least 48,000 acre feet of water per year from Poseidon.

In the first full budget year since the plant opened – July 1, 2016 to June 30, 2017 – the Water Authority ordered 49,600 acre feet of water from Poseidon. The plant only delivered 40,400, 18 percent less than the Water Authority asked for. Nearly all those shortfalls occurred in the first six months of this year.

As a result, Poseidon had to pay the Water Authority a penalty of $3.5 million – though the Water Authority still owed Poseidon $97.5 million for the water it did get. Despite its issues, the plant now produces about 10 percent of the region’s water.

“We have a very good story to tell,” said Peter MacLaggan, a senior vice president at the company. “The first year was exceptional in terms of performance. The second year we ran into some challenges, we’re addressing those challenges.”

The various problems at the plant include plant failures, regulatory wrinkles that will almost certainly be ironed out and some things beyond the plant’s control.

In April, for instance, the plant shut down for 15 days when an algal bloom along the coast soured the water. The plant was unable to treat any water without fouling up the expensive filters it uses to remove salt and other impurities from water.

Poseidon and IDE, an Israeli company that is hired to operate the plant, were apparently caught off guard by the algal bloom, which Riva called an “extreme” challenge.

Ron Watkins, a member of the Water Authority board, said he used to work at a power plant right next to the desalination plant. The plant fought algal bloom problems for years.

“It’s an issue you’re probably going to have to deal with for a long time, and perhaps in greater magnitude than you’re seeing this year,” he said.

Poseidon officials said they are changing their operations so they can produce drinking water even during future algal blooms, though they can’t guarantee they’ll be able to.

“We now have a battle plan for dealing with these situations, and we will learn from the next one and the one after that,” MacLaggan said.

Fortunately, the algal blooms near the plant seem to be associated with intense rainfall, so when they are most likely to happen, the region will least need the plant’s water.

In another significant shutdown, the plant was out of service for 10 days straight days in February for repairs to a water tank that had been causing problems since the plant opened.

The plant has also been shut down sporadically for inspections, tests and other water quality issues.

Other problems are a result of the unique way the plant gets water from the ocean.

The plant piggybacks off ocean water withdrawn by the adjacent power plant. The Encina Power Station uses ocean water to cool itself. The water from the power plant then goes to the desalination plant and then Poseidon tries to make it drinkable.

This arrangement has caused two problems.

First, sometimes the power plant is taken offline by its owner, NRG Energy. When the power plant is down, Poseidon can’t get ocean water, so it too must shut down.

Second, a state regulation sometimes prevents Poseidon from delivering water even if the water is clean and drinkable. State water regulators use the amount of salt in the water as a proxy for pathogens. Because salt molecules are far smaller than bacteria, if there’s not much salt in the water, there cannot be other nasty stuff. The problem for Poseidon is that water sometimes gets very hot when it passes through the power plant. When the temperatures rise too much, a bit more salt can make its way through the plant’s filters, even though worrisome toxins still cannot. The water is safe but can’t be sold.

Poseidon said it is working on a new way to test the plant’s water quality so the plant isn’t shut down because of temperature.

The power plant is also set to close soon and, once it does, Poseidon will have direct access to the ocean and won’t have to deal with hot water coming from the power plant.

“After that project is complete, the desal plant won’t be subject to temperature fluctuations beyond the seasonal changes, and the temperature issue will be resolved,” said Sean Sterchi, the top drinking water regulator for the San Diego region.

Besides the days it produced no water at all, on 73 days of the plant’s first 18 months in operation, it produced less than half of the 50 million gallons per day of drinkable water it is designed to make. Some of that low production is because of days the plant was dealing with less severe versions of the same issues that caused full-blown outages; other times the Water Authority simply may not have needed the water.

On other days, though, the plant has been able to make up some of the difference by producing more water than the 50 million gallons per day it is designed to: In early October, for instance, it produced about 53 million gallons of water for 16 straight days.

[divider] [/divider]

Originally posted at Voice of San Diego.