Microgrids Protect Essential Water Services for California Residents During Outages

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Communities can live without power, but they can’t survive without water. That’s  one of the reasons the Ventura County Public Works Agency’s water and sanitation department in California is planning a microgrid at its Moorpark Water Reclamation Facility, which serves low-income residents.

Batteries added to San Diego Zoo. Photo courtesy of PowerFlex.

Microgrid provider PowerFlex is financing and installing the microgrid, due to be installed during the second quarter of 2022. It also has plans for ensuring a different microgrid serves  the city of Thousand Oaks, California’s Hillside Canyon Waste Water Treatment Facility, said Michael Robinson, associate director of microgrids and new markets at PowerFlex, an EDF Renewables company.

The water facilities are subject to public safety power shutoffs (PSPS) from utility Southern California Edison (SCE), which means they must rely on polluting and expensive diesel backup generators during outages.

In Ventura County in 2020, SCE held PSPS 11 times in portions of Moorpark, Santa Susana and the Simi Valley, said a spokesman for Ventura County Public Works.

Right now, Ventura County’s Moorpark facility has about 1 MW of solar — plus a diesel generator that’s used during outages, said Robinson. Without a microgrid, when there’s an outage, the solar goes offline. With the microgrid, the solar will continue to operate, and for a longer time period during outages, thanks in part to the 750-KW, 3,000-KWh battery that’s part of the microgrid.

The Thousand Oaks project faces the same challenges, and PowerFlex plans a similar solution.

Both microgrids will receive funding from the equity resilience budget of California’s Self-Generation Incentive Program (SGIP), which is available to low-income and disadvantaged communities that need energy resilience.

In the Ventura County case, the microgrid project is eligible for a $1,000/kWh incentive because it’s located in a high fire threat district, provides critical facilities infrastructure — sewage treatment — and serves a community that includes low-income residents. The total payment from SGIP will be $1,992,050, said Homer Arredondo, an engineer for Ventura County Public Works’ water and sanitation department.

Under a financing arrangement from PowerFlex, the Ventura County and Thousand Oaks projects require no upfront payments. PowerFlex collects the SGIP incentives from the state, leases the microgrid equipment to its customers and is paid back through monthly payments.

“You could call it an energy-as-a-service contract,” said Robinson. “We finance it, we are responsible for operations during both grid-connected times and power outages. We generate savings so the savings cover the cost of the customer’s lease payments.”

The state of California provides 50% of the SGIP payment upfront, and the other 50% is paid out over a 5-year period, based on the number of battery cycles, said Robinson. A battery has completed one cycle when it fully charges and discharges. Generally, a battery cycles about 300 times a year, he said.

The microgrid at the Ventura County Public Works Agency is expected to save the district and its customers $355,400 over the 15-year life of the battery by reducing demand charges as well as energy charges during on-peak, time-of-use tariff periods, said Arredondo.
First, the microgrid will allow the company to use the solar and battery to reduce demand charges. Second, the microgrid will reduce the agency’s energy costs by taking advantage of SCE’s time-of-use tariff (TOU-PA3E tariff). The solar will charge the battery during less expensive off-peak hours, and the battery will be discharged during expensive peak rate times, which occur between 4 p.m. and 9 p.m., said Arredondo.

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PowerFlex won’t use the microgrid for demand response programs because it’s more economical to do demand reduction and participate in time-of-use rates, said Hamilton.

To ensure the solar panels continue to provide power during an outage and the microgrid islands, PowerFlex will change the electrical writing of the facility, Robinson explained.

The company reconfigures the wiring so the solar doesn’t push power back onto the grid, which could shock a lineman, for example. To allow a solar system to island, PowerFlex adds both physical assets and software, creating a microgrid.

The planned microgrids will allow both Ventura County and Thousand Oaks to reduce diesel use by preventing solar systems from shutting down during outages.

The Ventura County and Thousand Oaks facilities need to operate all day every day. Currently, if a power outage occurs, the agencies need to operate diesel 24/7 during an outage, said Robinson. With the microgrids, if the solar panels are harvesting sunlight, little diesel will be needed.

The benefits of the microgrid at the Ventura County facility are numerous, said Arredondo.

“The microgrid allows the district to further modernize the power system operation at Moorpark Water Reclamation Facility, resulting in a reduction in our operational expenses, increasing our resiliency and improving the quality of service we provide to our customers,” he said.

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  1. “The water facilities are subject to public safety power shutoffs (PSPS) from utility Southern California Edison (SCE), which means they must rely on polluting and expensive diesel backup generators during outages.”

    There’s an interesting aside in this tale. Waste Water treatment plants can have two different treatment pathways. Aerobic digester or Anaerobic digester activation. Aerobic digester (open system oxygen added) is the easier of the two, but it still off gasses, methane and CO2 in the process. Anaerobic digesters (closed system sans oxygen) are designed to use different bacteria that when used in the digester, off gasses and captures a mix of gasses which are scrubbed and can be stored for later use in a typical engine generator set. This operation has been used to collect burnable gasses to use in the waste water process to power the plant for power shedding, peak demand shedding or standby power use. These Waste Water Recycling Plants sometimes referred to as WRPs (warps) can become more efficient by using the bacteriological break down of waste to catch, store, and use later the gasses for fuel to help run the plant. Add solar PV and large energy storage to complete the micro-grid and an efficient treatment process one has designed.