City eyes recent land purchase for power plant

Jun. 28—In April, the City of Mesa finalized a deal to purchase 9 acres of vacant land at the northeast corner of University and Stapley drives from the U.S. Government for $2.6 million.

In the quitclaim deed transferring the property to the city, the U.S. General Services Administration stated the property was "duly determined to be surplus to the needs and requirements of the United States of America."

The GSA first offered the land to the city in June of 2021 and the city accepted.

The site is next to the Rogers Substation, the point of entry for electricity into Mesa's city-owned electric utilit that serves about 17,500 residential and commercial customers inside 5.5 square miles of the city's core.

The 9-acre Rogers Substation site is surrounded by residential neighborhoods and public facilities, including Hughes Elementary School and the Mesa Public Schools Curriculum Services building to the north.

In April, Energy Resources Program Manager Tony Cadorin told City Council his department was studying options for the site, including a "large-scale" 30 megawatt natural gas-burning power plant or a utility-scale battery storage facility.

Earlier this month, Cadorin signaled that the city is leaning toward the gas plant, presenting the Sustainability and Transportation Committee with a detailed explanation of the benefits for Mesa in building its own natural gas-burning facility.

The sustainability committee is made up of three council members and is currently chaired by Councilwoman Alicia Goforth.

The crux of Cadorin's case was that in order to increase the amount of renewable energy sources in the city utility's energy portfolio, Mesa needs to add more "local, dynamic" power sources, or power sources that can increase power to the grid quickly

Natural gas is a fossil fuel that emits CO2 into the atmosphere when it burns, but Cadorin argued that even if a dynamic source is not green, the overall impact would be the greening of the city's energy portfolio.

"I think people have just an instant aversion to (natural gas). 'Oh, you're adding natural gas generation. Don't do that.' Well, we're doing this for a reason," Cadorin told committee members.

"Without these flexible, dynamic resources, we just simply can't add much more solar" to the grid, he said.

A big battery could perform the same function as a plant, but Cadorin said the technology was still expensive and the city has some concerns about safety, as there was an explosion at a battery facility in Peoria in 2019 and fire at a Chandler facility in 2022.

Between the city's long-term contracts for hydropower, a recent solar power contract with SRP and new installations of city- and customer-owned panels, Mesa's electric utility is up to 40% renewable energy, he said.

Cadorin said a big city-owned natural gas plant would allow the city to bring up its renewable portfolio to 63%.

He called this level of renewables "industry leading in the state."

He added that energy demands in the Southwest are growing, and many utilities are replacing coal and gas fired plants with variable energy sources like solar and wind.

Because there is a gap between peak solar production and peak demand for energy on a daily and seasonal basis, Cadorin said his department worries that the frequency of grid "instability" could grow in the future and make the open energy market costlier.

"We can't put all our eggs in one basket," he said.

As far as the location of the gas plant, Cadorin argued for the 9-acre site near Hughes Elementary.

"This is a site that's not really well-suited for residential development or commercial development," he said.

"It's surrounded by very large high-voltage electric facilities, so we view this as a great opportunity to develop larger energy resources than we've historically done."

"I think some people have an aversion, 'Oh, there's gonna be a power plant in my neighborhood.' Well, there's certainly examples that we've seen where ... it's actually a very beautiful building."

In response to a question from Vice Mayor Francisco Heredia about negative impacts from a power plant on the surrounding area, city staff said they had worked hard on plans to get sound generated by a plant down to "the level of conversation."

Conversation produces sounds around 60 decibels, which according to the Noise Project, an initiative funded by the National Science Foundation, presents a low risk for hearing damage.

However, exposure to this level of noise for "prolonged periods" can cause indirect health impacts from an "increase in stress hormones, either through sleep deprivation, anger/annoyance, or disrupting your performance or communication."

Regarding air quality, staff said the city would have to obtain all the relevant permits from the state to ensure they are in compliance.

After the presentation, Goforth thanked the Energy Department for its efforts and expressed support for diversifying and adding renewables to the electric utility's portfolio.

She told the Tribune that she's "open to all options for getting to cleaner and renewable sources" of energy and wouldn't take building a gas plant "off the table."

"I'm interested in hearing more about it, and then doing more research on it," she said.