Bond, lease, or power deal
A general obligation bond is the straightforward path. Voters approve it, the district borrows against future property taxes, and the district owns the solar array outright. Owning it means the district keeps all the savings on its power bill and any incentives, but it also carries the upkeep and the risk if a part fails early. Bonds in Arizona are capital money, so they fit panels and canopies well, which are long-lived equipment rather than yearly operating costs.
The other common path is a power purchase agreement (PPA) or a lease, where a private company owns the system, installs it at little or no upfront cost, and sells the school the electricity, usually at a rate set below the utility's. A PPA moves the maintenance and the early-failure risk off the district's books, which is the main appeal for a district without bond room. The trade is that the savings are thinner, because the company has to earn its return, and the contract can run twenty years or more. Neither path is automatically better; it depends on whether the district has bond capacity and how much risk it wants to hold.
What the savings actually look like
The biggest single factor is the utility and its rate. Salt River Project (SRP) and Arizona Public Service (APS) both bill large customers partly on demand (the single highest spike of power use in a month, not just the total), and a school's demand peak often lands on a hot afternoon when the air conditioning is flat out. Rooftop and canopy solar can shave that afternoon peak, which is where a lot of the real money is, but only if the system is sized and pointed for it. A reader comparing two districts' results should check which utility each sits in before assuming the numbers transfer.
Export rules matter too. Arizona no longer has old-style net metering; after the Arizona Corporation Commission (ACC) decision in the mid-2010s, utilities pay a lower export rate for power a solar system sends back to the grid than the retail price. For a school that uses most of its own daytime power, which most do, that matters less, because the best value is the power the building consumes on site rather than what it exports. Savings worth a meaningful share of a school's power bill are plausible at last public reporting, but treat any single headline figure as a starting point, not a promise.
The maintenance nobody budgets for
Panels have no moving parts, which is where the low-maintenance reputation comes from, but the desert is hard on hardware. Dust settles between the infrequent rains and cuts output, and a single haboob (the wall of dust that rolls in during monsoon season, roughly June through September) can coat an array in an afternoon. Cleaning is cheap but not free, and skipping it quietly eats the savings. Inverters, the boxes that convert the panels' output into usable building power, are the part most likely to need replacing, often somewhere around the ten to fifteen year mark.
This is the real difference between owning and a PPA. Under a PPA, the company is on the hook for cleaning and repairs, and the school gets a predictable bill. Under a bond-funded, district-owned system, the savings are larger on paper, but the district has to fund cleaning, monitoring, and eventual inverter replacement out of its own budget, and those are the line items that get cut first in a tight year. A district that owns its array without a maintenance plan is the one most likely to be disappointed.
Worth watching this month
1. Watch school district governing board agendas this fall, since several Arizona districts place bond and override questions on the November ballot and the solar items usually appear in the project detail.
2. At the Arizona Corporation Commission, watch any open docket touching APS export rates or rate design, because a change there moves the math for every APS-territory school, though these dockets routinely move slowly.
3. In SRP territory, watch SRP's board and its price-plan updates, since SRP sets its own rates outside ACC review and its demand charges drive school solar savings.
4. Watch for monsoon-recovery output reports from districts with existing arrays, a routine but telling check on how much dust and storms actually cost over the summer.