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CASTLE ROCK RD
WALNUT CREEK, CA

Based on surrounding parcels, Castle Rock Rd in Walnut Creek, CA 94598 is a low-density residential and A2 agricultural-zoned corridor featuring large-lot single-family homes and equestrian/ranch properties. No significant commercial energy load is expected; typical residential utility demand applies.

System layout — solar carports at WALNUT CREEK
System layout — solar carports

Projected savings.

Year 1

$76,300

Lifetime (~30 yr)

$5,692,000

By the numbers.

3.9

Years to payback

$13.5M

Total benefits (lifetime)

$7.8M

Property value gain

$622,197

Tax incentives captured

Levelized cost of electricity

$0.06 / kWh · SolarPorts
vs.
$1.15 / kWh · PG&E

Like most WALNUT CREEK 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 $1.15/kWh from PG&E, reduced to $0.06/kWh from SolarPorts.

SolarPorts evaluated their interval power usage (every 15 minutes) and proposed a right-sized 105 kW solar system for on-site generation delivered as 7 SolarPort carport structures above the parking lot.

The system now produces roughly 164,640 AC kWh of clean energy each year, an estimated $76,300 in year-one utility offsets, and around $5,692,000 in net lifetime savings — turning a recurring operating-cost into a long-term, predictable energy hedge.

System spec

System design

Site
CASTLE ROCK RD
WALNUT CREEK, CA 94598
APN
138270002
Utility
PG&E
Seismic rating
1.6
Irradiance
2
System size
105.0 kW DC
Estimated production
164,640 AC kWh / year
Year-1 utility offset
$76,300
Lifetime savings (~30 yr)
$5,692,000
Solar panels
210 × Trina 480 BiFacial
SolarPort structures
7
Wire loss
2.0%

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