One morning in late May, Brittany Coates sat on the back of a bench with her feet on its seat, listening to music as she waited for a ride to work. A cool breeze swept through the Tohono Tadai transit center, chasing out the exhaust from the idling silver and blue buses.
Raising her voice to be heard over the rumbling of the engines, Coates was quick to offer her opinion on Tucson studying whether the city should invest in a massive solar-energy plan. The plan could make Tucson a leader among the budding number of Arizona cities and tribal nations investing in this type of renewable energy. An initial proposal calls for placing panels across 15 miles in the city, stretching from the Tohono Tadai transit station, through downtown to the Tucson International Airport.
“We get enough sun here and shit. We should be doing everything solar,” Coates said. “I’m surprised they haven’t tried to do something like this earlier.”
Ward 6 Council member Steve Kozachik proposed the solar-powered microgrid project at a May 23 City Council Study Session. Owned and operated by the city of Tucson, the project, coined Solar ROW Microgrids, could potentially power a form of electric public transportation like Tucson’s streetcar.
The council and Mayor Regina Romero voted to send the proposal, which is in its initial stages, to the Climate Action Team made up of city officials and the Commission on Climate, Energy, and Sustainability, a citizen’s commission composed of community members that is independent of the city staff.
The two groups will review the proposal and issue a report in September.
“I want to get as many eyeballs on it as possible,” Kozachik told Arizona Luminaria. “I want to get them to be looking at [the proposal] and poke holes in it.”
Jim Sell is the commission’s new chairperson and is a retired professor of geography and sustainability. Sell told Luminaria he has a lot of questions about the proposal.
Those questions include the total cost of the project and the amount of electricity it would generate, where the microgrid would be, and whether or not Tucson Electric Power will be involved.
The commission plans to discuss the proposal and the potential of forming a sub-committee to further examine it at their meeting on June 28.
We’ve heard from many Luminaria readers who want to learn about issues early, so they have time to get involved and decide how they want to guide civic and community actions. So Luminaria made this guide to break down your burning questions about what microgrids are and what they might mean for Tucson.
What is a microgrid?
A microgrid is a miniaturized version of an energy grid that is able to provide power on its own and disconnect and reconnect from the larger electrical grid at will, said Nathan Johnson, assistant professor of engineering at Arizona State University, in an interview with Luminaria.
Microgrids can be powered by many different sources of energy. However, they are often seen as a way to use more renewable energy because they can take advantage of an area’s natural resources – like Arizona’s sunshine.
There is no definite data about how many microgrids exist in Arizona. A map created by the U.S. Department of Energy identifies 3 microgrids in the state of Arizona with data current to 2022; however, there are microgrids not displayed on the map, such as one at a data storage center in Phoenix.
Arizona lags far behind California and Texas, two of the states with the most microgrids. The map lists California as having 92 projects and Texas as having a whopping 257.
Many of Texas’s microgrids power small stores like Buc-ee’s, a chain of general stores and gas stations that partnered with electric companies to build natural-gas-powered microgrids at its stores in 2016.
Caterpillar runs the only microgrid near Tucson at a site in Green Valley where it tests its mining equipment. A combination of solar panels and a backup generator create power.
Microgrids are different from backup power because “if the grid goes down, then the building or community isolates and then turns on backup generation, but you can’t leave that backup generation active — that’s a very important distinction,” said Johnson, who is also the director of ASU’s Laboratory for Energy and Power Solutions.
Alternatively, because a microgrid is able to disconnect from the central grid, it can keep providing power if there is a wide-scale power outage.
Researchers are examining microgrids as a potential solution to a growing number of climate-change-fueled blackouts, according to a report by the University of Wisconsin-Milwaukee.
A model for what Tucson is proposing can be found in Puerto Rico, where community members recently built a large solar-powered microgrid. Owned and managed by the community, approximately 700 solar panels provide a steady source of power in case of outages caused by Puerto Rico’s increasingly intense hurricanes.
Microgrids are also often confused with “minigrids,” which are not connected to the larger grid at all, Johnson said.
Unlike large, centralized grids that carry electricity from a single power plant across long distances, microgrids are localized sources of power, which means that they create energy for use nearby, according to Microgrid Knowledge, a microgrid provider.
This feature of microgrids means they can bring power to rural areas where it is challenging to connect homes and businesses to the larger grid.
For example, the Navajo Nation, Hopi and San Carlos Apache Tribes all have recently received federal funding to build microgrids that will help power homes, water pumps and hospital buildings.
Where would the solar panels be placed and what would they be used for?
Kozachik’s proposal, which features a microgrid powered exclusively by solar panels, suggests placing the panels along a 15-mile route named Tucson Norte-Sur.
The route that starts at Tohono Tadai transit center before cutting through downtown from Tucson Mall to the airport is not new but has been a topic of conversation recently.
In 2020, the Federal Transit Administration awarded the city of Tucson nearly $1 million dollars to create an equitable transit-oriented development plan in the area.
Equitable transit-oriented development is an approach to design and build walkable, mixed-use neighborhoods with access to public transportation without gentrifying low-income areas and displacing people of color, according to the city’s website.
Tucson chose this route as a potential area for future transit development because it includes the most popular SunTran routes and accounts for 15% of all Tucson public transit ridership, according to a presentation at an open house for the project.
In addition, along the route 74% of residents are people of color, and 57% are rent-burdened households, defined as when a household spends more than 30% of their income on rent or other housing costs according to research done by the city.
Kozachik suggested the solar microgrid run along the Tucson Norte-Sur route because the city is already examining it for development.
“We hope to use that route for either a hybrid trolley or streetcar, you know, some sort of electrified transit,” Kozachik said. “Since we’re doing it there anyway, let’s try and layer this idea on top of it.”
The city could place solar panels to shade the sidewalks and bike lanes along the route, he said.
The microgrid could contribute to Tucson’s goal of equitable transit-oriented development by providing cheaper power to adjacent homes and businesses.
“When people are looking at the cost of homeownership, utility expenses is a real one,” Kozachik said. “We’re talking about providing an alternative, off-the-grid energy source that is less costly, that can be used for things such as affordable housing along the way.”
Sell, the citizen commission’s chairman, wants to think carefully about how to use the power generated by the microgrid and where to place it.
“Suppose electricity goes down for a week in town,” Sell said. “Do we need to have a streetcar that still operates? Probably. But is it more important than air-conditioned shelters [or] medical facilities being up and running?”
The tentative proposal does not yet include how much power the microgrid could generate. That will ultimately depend on how many solar panels the city builds.
“If we build a mile of [Tucson Norte-Sur] or if we go 15 miles of that it will completely change the dynamics. The longer it gets, the bigger it is, the more power you can generate,” Kozachik said.
How much would electricity cost? And would Tucson Electric Power be involved?
In the background of the proposal for the solar microgrid is a larger debate in Tucson over the cost of electricity and the future of the grid as the temperature and population increase.
Tucson voters recently denied Proposition 412, which would have added a 0.75% fee to the electric bills of TEP customers to put controversial power lines underground and fund climate-related projects.
Prop. 412 and other proposed rate increases are TEP’s response to having more customers using more energy, said Joe Barrios, TEP’s supervisor of media relations, in an April Luminaria article.
Sell said one of the questions he has is how TEP will fit into the plan for the microgrid.
“Is this supposed to be a standalone, grow-your-own utility that’s apart from TEP? Which is not exactly something they’ll be attracted to,” Sell said.
Kozachik said he wants the microgrid to be operated and owned by the city, not TEP. How that would work remains to be seen, because while microgrids can run locally and independently, they typically tie into a central grid.
Barrios told Luminaria in early June that TEP would need more information about the proposal before he could comment on it specifically.
He added that TEP currently works with many customers who have their own energy-producing systems like solar panels. He said their decisions about those systems are entirely up to the customer.
“It’s important to remember that when a customer decides to install a system on their side of the meter, it is their system,” Barrios said. “We operate power plants, we operate transmission lines … and then our service literally ends at the meter.”
The microgrid, if built, would be the first city-owned source of power.
Kozachik wants to offer Tucsonans more options for power to provide competition with TEP to drive down electricity costs.
“This is all about getting us … decoupled from the TEP stranglehold that they’ve got on where we get our power,” Kozachik told Luminaria. “To the extent that we can offer more options in the marketplace, then competition is a good thing, monopolies or not, when it comes to cost issues.”
Kozachik said the type of power provided by the microgrid would be cheaper than that provided by TEP.
However, Johnson said the power generated by a microgrid is not necessarily cheaper than that provided by a utility.
“It’s possible, but it depends on the local costs [and] technology,” he said.
Kozachik said the city is working through those issues.
Tucson has not yet allocated funding for the project or applied for any grants, because they are still working out the details of the proposal.
The funding pilot information on the proposal’s website suggests applying for a federal grant for “investments in surface transportation infrastructure that will have a significant local or regional impact.”
What’s next?
On that breezy day in May when Coates was questioning why Tucson hadn’t already invested in this type of solar energy, Shannon Bass was also at the Tohono Tadai transit center waiting for a bus.
For Bass, equity in transit and community resources hits home. She used to live on the streets, taking shelter in the neighborhood around the transit center before Old Pueblo Community Services and the city of Tucson helped her find housing.
“So I take the bus everywhere, all day,” Bass said with a laugh.
She pointed to the fact that Tucson is growing as a reason to build the solar microgrid.
As the city starts digging into and refining the solar microgrid proposal, Bass would like officials to think bigger.
“I think we should have this all over town,” Bass said.
Before stepping into the waiting bus, Bass smiled and said she’s excited to see it happen.
How to get involved
To weigh in on Tucson’s solar microgrid idea, attend the Commission on Climate, Energy, and Sustainability’s remote meeting on June 28. Meeting information will be posted at the “current agenda” link when it becomes available.
Share your opinions with Steve Kozachik and Ward 6 staff at (520) 791-4601 or email ward6@tucsonaz.gov. Or contact your city council representative here.
Republish our articles for free, online or in print.
