District solar portfolio met 95% of weather-adjusted expectations and produced roughly $622,000 in bill savings, advisor says

An independent advisor reported that the district’s solar and battery portfolio produced savings and performed close to expectations in fiscal year 2023–24, but the district faces program decisions about ownership, future inverter replacement and EV-charging costs.

David Burdick of TerraVerde Energy said the district’s nine solar installations — each roughly 100–200 kilowatts and coming online in 2018 under third-party ownership — operated at about 95% of weather-adjusted expectations. Burdick told the board the portfolio “harvested $622,000 of bill savings,” meaning that if the district had not deployed the solar facilities its general fund utility costs would have been about $622,000 higher last fiscal year.

TerraVerde presented month-by-month production versus weather-adjusted expectations and described variability in winter months and stronger performance in some summer months. Burdick said the district’s solar systems outperform many districts that have third-party ownership, where performance can fall into the 50–80% range. He also said two inverters were currently out of service (reported at Locke and Egan), and TerraVerde was coordinating with the third-party owner, Forefront, to dispatch technicians.

The presentation outlined other operational details and decisions trustees raised in Q&A: electricity usage across district sites has risen overall since the solar installations (TerraVerde reported district consumption was up roughly 17–18% over the fiscal year), yet the district is buying about 34% fewer kilowatt-hours from the utility than it did before the solar array deployments. Burdick said the higher-than-projected avoided-cost total was driven by larger-than-expected utility-rate escalation, which increased the dollar value of each kilowatt-hour offset by solar.

Board members asked about EV charging (costs and usage) and whether the district should consider buying out the power purchase agreement (PPA). Burdick said most PPA contracts include buyout provisions at set operational anniversaries — commonly at the end of five or six years and again at later anniversaries — and the typical contract term is 20–25 years. He explained buyouts are possible but “not a straightforward transaction,” with fair-market valuations often above the stated termination value; if the district used bond funds to buy out a PPA, the district would assume operation and maintenance and equipment-replacement costs, including future inverter replacement.

Burdick estimated string inverters typically have an expected useful life of roughly 10–15 years (he suggested many sites could be toward the 15-year range in a moderate climate) and said panel arrays themselves generally last far longer. Forefront currently covers operating costs and technician dispatch under the third-party agreement, Burdick said.

Trustees asked TerraVerde to provide further analysis on EV charger usage and costs and to prepare a buyout/ownership study if the board wished to evaluate that option given recent bond passage and availability of capital.