From The Editor | October 17, 2016

How Treatment Plants Can Access Solar Energy

Peter Chawaga - editor

By Peter Chawaga

When you talk about costs at a water treatment plant, you’re almost always talking about energy use.

According to the U.S. EPA, drinking and wastewater treatment plants account for 30 to 40 percent of the total energy consumed by a given municipality and as much as 40 percent of operating costs for drinking water systems can be for energy.

In California, where water issues of all types seem to be under a magnifying glass, innovative energy use is no different. Southern California’s Metropolitan Water District (MWD) has been a leader in utilizing the power of the sun to offset the exorbitant cost of cleaning drinking water. Most recently, it announced a $6.76 million investment to build a solar-power generating facility at its Joseph Jensen Water Treatment Plant in Granada Hills.

The project, which MWD expects to produce 2.3 million kWh of energy per year, will take up six acres of the plant’s 125-acre plot and eventually pay for itself.

“The expected payback on that system … we’re estimating that one to be between 10 and a half to 12 and a half years,” said Mike Rojas, head of MWD facility development section.

In the instance that excess energy is generated, it will go towards maintaining the district’s metering system.

“That’s a really good part, because it’s behind the meter and we have a net metering agreement with Southern California Edison,” said Rojas. “In times where we may generate more than we need, then that power will be credited to Metropolitan and it will result in a reduction of cost in other Edison meters that we have in the system, so it will be credited back to us.”

The Joseph Jensen addition is the latest in a long line of such solar efforts from the district. Its first large solar project was installed at the Robert A. Skinner Water Treatment Plant in Winchester, CA, in 2009. It recently finished a project at its F.E. Weymouth Treatment Plant in La Verne, CA and has another at the Diamond Valley Lake Visitor Center in Hemet, CA.

This most recent solar facility was financed through a MWD capital investment program that is funded from a combination of debt-financed revenue bonds and current revenues, according to Rojas.

“Now, the other aspect to this is there are rebate incentives out there for solar projects, and those help make the economics better for Metropolitan to make these investments in solar projects,” Rojas said.

MWD can receive a $1.4 million rebate via the Los Angeles Department of Water and Power’s Solar Incentive Program if the project begins operating within 2017, before the rebate expires.

“We anticipate [the facility] to be online close to the end of 2017,” Rojas said. “We will probably complete construction in the August to September timeframe, and then we’ll be doing testing, commissioning, and validation for several months. We expect to be up and running before the end of the year in 2017.”

Although MWD may be better poised to reap the benefits of solar installation than other water districts thanks to its size and the rebates it can collect, Rojas is optimistic that other utilities can implement similar programs that at least offset some of their energy costs.

“What we’ve seen since 2009 when we completed the installation at Skinner is a big price drop in the cost to implement solar,” he said. “Panel production is becoming more of a standard process. Costs are dropping.”

As a first step, Rojas recommends researching the rebates that may be available in a given area and then making haste to capitalize on them.

“If [the utility is] small or doesn’t have its own engineering department, it would want to connect with a consultant who could help plant out a system, do the design, help get bids, and proceed quickly,” Rojas said. “If you wait, prices will still go lower, but the benefits, the rebates, they’re going to be gone.”