Emergency Generators to Move Water During Power Shutoffs

When high temperatures, extreme dryness, and record-high winds create conditions where a spark might lead to a major wildfire and threaten a portion of the electric grid, PG&E turns off the electricity. This is known as a Public Safety Power Shutoff (PSPS). And when PG&E shuts off the power at critical pump stations, the District is unable to pump water into reservoirs—water that may be needed to fight fires.

In 2019, the District experienced a few brief power shutoffs at pump station sites in western Dublin. At the time there were only two pump stations in the District’s water distribution system equipped with emergency generators. Operations and Engineering staff went to work. They identified 7 of the District’s 17 pump stations as critical to operating the water system. These seven pump stations move water to reservoirs on the edges of the water distribution system and are critical to providing water to all pressure zones.

“Our goal is to be able to handle any threat to the water distribution system in an emergency and to maintain water service for most, if not all, of our customers,” says Associate Engineer Sean O’Reilly, the project manager responsible for designing and installing six of the emergency generators and portable generator tap boxes. Tap boxes are the electrical wiring connections outside of the pump stations which enable operators to quickly plug in the emergency portable generators and provide power to the pump stations. 

Two portable generators sit on trailers, ready for use if needed.

About the Generators

Two of the seven generators will be permanently installed at two critical pump stations: 4B that moves water (and the sole source for fire protection) to the Schaefer Ranch community and 200A that moves water to Dougherty Valley. These are the District’s outer most areas of service, and the emergency generators at these pump stations should be operational by the end of 2021. 

Five of the emergency generators are portable so they can be moved on short notice wherever they are needed. Given the power needs of the various pump stations, the District purchased three 130-kilowatt (kW) generators and two 250-kW generators, which combined will meet the District’s needs at the critical and less critical pump stations throughout the water distribution system. Each portable generator is about the size of an airstream trailer and can be hauled in place by a mid-size pickup truck equipped with a trailer hitch. The District has 15 such trucks and 15 operators/mechanics capable of towing the emergency generators. These portable emergency generators should be operational by late summer 2021.

The most critical pump station, 1A, is being rebuilt under a separate contract and will receive one of the portable emergency generators and a tap box. This project is being managed by Assistant Engineer Jose Oropeza. 

In addition to purchasing emergency generators and rewiring pump stations so the portable generators can be plugged in quickly, the District is also installing uninterruptible power supplies at eight reservoirs. An uninterruptible power supply is essentially a 24-hour battery that enables remote sites (e.g., reservoirs, pump stations) to transmit data (e.g., water levels in the reservoirs). In an emergency it is important for the reservoir sensors and communication equipment to be operational, so the pump station knows when to pump and when to shut off. If the pump station does not know the volume in the reservoir, it will not turn on. Uninterruptible power supplies will provide consistent power to sensors and communication equipment at the reservoir sites. Reservoirs are filled automatically by their respective pressure zone pump stations, and it is critical for the data stream from reservoirs to the pump stations remains uninterrupted. It is also important that the water system operators in the control room at the Field Operations Facility and out in the field on their wireless devices have current, accurate information.

Cost Savings

The total cost of this project is $3.42 million dollars. The District saved approximately $50,000 by purchasing the Cummins emergency portable generators via SourceWell, a procurement resource that enables bulk buying for public agencies. Of the three emergency generator vendors, only Cummins Inc. (Columbus, Indiana) provides the size of generators the District needs that match the power demand for the District’s critical pump stations. 

Downside of Emergency Generators

There are downsides to emergency generators. They generate a lot of heat. They are noisy. And they pollute the air. 

Regarding air pollution from the emergency generators, the District will need to get permits to operate them. For the portable generators, the District will request a permit from the California Air Resource Board. For the permanent standby generators, the District will request a permit from the Bay Area Air Quality Management District. All of the generators will comply with local, state, and federal emissions requirements.

Also, because water operators need to test the emergency generators regularly to ensure they are working properly and ready for an emergency, the air quality permit will allow operators to run the generators 50 hours a year for testing and training, and up to 24 hours a day for the duration of a power outage emergency. 

Regarding noise, District staff is working with the cities of Dublin and San Ramon to receive variances to operate the generators in an emergency, especially generators used at pump stations located close to homes and businesses.

The emergency portable generators are powered by diesel fuel typically stored separately from the emergency generators. Emergency generators cannot be transported with a tank full of diesel, and District staff can transport no more than 100 gallons of diesel at a time. That said, there is a limit on how much fuel a generator can contain; only enough to operate for around 24 hours. Depending on the models, when fully fueled, both the portable and stationary emergency generators can run for 24 to 35 hours.

Even with all these downsides, in the event of an emergency, emergency generators can save lives by providing much needed water, especially in the event of wildfires.

“This project may not be the most glamorous, but it’s very important and critical that we are able to distribute water throughout our system and protect against fire,” O’Reilly says.

Posted: June 16, 2021