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1700 Petaluma Marshall Rd Bldg 31
PETALUMA, CA

Walker Creek Ranch (Bldg 31) at 1700 Petaluma Marshall Rd is a multi-building retreat and conference campus owned by the Marin County Office of Education, spanning 1,700 acres with lodges, dining halls, and overnight dormitories. The site supports year-round residential outdoor education programs and private events, driving continuous HVAC, kitc...

System layout — solar carports and rooftop arrays at PETALUMA
System layout — solar carports and rooftop arrays

Projected savings.

Year 1

$240,200

Lifetime (~30 yr)

$35,925,000

By the numbers.

1.1

Years to payback

$105.2M

Total benefits (lifetime)

$69.3M

Property value gain

$743,512

Tax incentives captured

Levelized cost of electricity

$0.02 / kWh · SolarPorts
vs.
$2.42 / kWh · PG&E

Like most PETALUMA businesses, the site was paying high Peak rates and large Demand charges — the kind of bill structure that punishes daytime energy use and penalizes the very hours commercial properties consume the most power. The result was a Levelized Cost Of Energy (LCOE) of $2.42/kWh from PG&E, reduced to $0.02/kWh from SolarPorts.

SolarPorts evaluated their interval power usage (every 15 minutes) and proposed a right-sized 263 kW solar system for on-site generation delivered as 3 SolarPort carport structures above the parking lot and a rooftop array on the building.

The system now produces roughly 495,207 AC kWh of clean energy each year, an estimated $240,200 in year-one utility offsets, and around $35,925,000 in net lifetime savings — turning a recurring operating-cost into a long-term, predictable energy hedge.

System spec

System design

Site
1700 Petaluma Marshall Rd Bldg 31
PETALUMA, CA 94952-9457
APN
106-200-08
Utility
PG&E
Seismic rating
1.2
Irradiance
2
System size
262.5 kW DC
Estimated production
495,207 AC kWh / year
Year-1 utility offset
$240,200
Lifetime savings (~30 yr)
$35,925,000
Solar panels
420 × Q.TRON XL-G2.3/BFG
(180 carport · 240 rooftop)
SolarPort structures
3
Wire loss
2.0%

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