Updated analysis: Glendale police station solar payback shifts slightly, remains positive over 25 years

City staff presented an updated cost and rate-of-return analysis for rooftop solar at the Glendale police station and discussed installation constraints and warranty coverage.

The police chief told the council Clark Dietz reviewed roof life and warranties and concluded the payback period would move from the earlier 17–18 years to roughly 19–20 years under the updated roof-life assumptions. The chief said the roof is about seven years old, carries a 20‑year manufacturer’s warranty and an estimated maximum service life of about 35 years. Using Clark Dietz’s numbers, staff said a total project cost of $304,000 (including financing assumptions) would produce an estimated $183,000 net positive return over a 25‑year analysis period.

Council members asked whether the manufacturer warranty included labor. Staff and the Clark Dietz representative clarified the warranty covered parts (panels) but not long-term labor; a one‑year labor warranty was discussed for installation. Councilors also raised an electrical-panel constraint that limits how much additional solar capacity can be added without panel or breaker upgrades; staff said the project team considered other options and that rooftop installation was the feasible option for the site.

There was no motion on the update; staff said the contractor bid opens the next morning and that any solar installation would be handled as a change order to the larger renovation project and brought back for formal approval if the change order exceeded signing authority.

What this means The updated estimate modestly lengthens the payback timetable but retains a positive net present outcome over 25 years, according to the analysis presented. Council members signaled general support to continue, subject to final bids and any required electrical upgrades.