Apache Solar I
Apache Solar I, located at Apache Generating Station, provides 20 megawatts of renewable power to:
Our 6 Class A member cooperatives
Electrical District No. 2, a public power utility in Casa Grande, Arizona
Apache Solar Fast Facts:
20
Megawatt (MW) AC power generated
3000
panels
320
watts produced by each panel
134
acres of AEPCO property house the solar array
9
2.5-MW inverters convert the DC power to AC
SunAnza
We partnered with our Class A member Anza Electric Cooperative (AEC) to complete SunAnza:
A 3.4-MW solar and battery energy storage project
Helps AEC meet California’s renewable energy standards
SunAnza Facility Construction
Anza, California, is a small, remote community in the high-desert mountains above Palm Springs. Its growth is limited by the single Southern California Edison transmission line that has inadequate capacity to provide for load growth in the area. Unfortunately, the transmission line is among the least reliable in California — but created excellent conditions for testing a microgrid to supplement AEC’s power.
2017
- Sierra Southwest Cooperative Services, AEPCO’s sister organization, completed and placed in service the 2-MW SunAnza project on behalf of Anza Electric Cooperative.
- AEPCO worked with AEC, the National Rural Electric Cooperative Association, and the U.S. Department of Energy to study the benefits and costs of various designs.
2019
In late 2019, the team settled on a design to add:
- 1.35 MW of solar power
- 4 MWh of Tier 1 battery storage
- Microgrid control technology
2020
Construction was completed in December 2020
Battery Storage Expansion and Microgrid Control
The new battery storage system with microgrid control:
Provides an additional 5.2 MWh of battery storage.
Allows AEC to be better positioned to respond to power or transmission outages.
Allows energy generated during solar hours to be shifted to late afternoon or night—when electric loads typically peak—to reduce more costly power supply costs during these hours.
Cooperative Lender Financing
AEPCO’s financial team worked with cooperative lender CoBank to finance this project through a lease-back arrangement between its sister organization, Sierra Southwest Cooperative Services, and CoBank’s Farm Credit Leasing subsidiary. This lease structure provides a repeatable formula that:
Allows our cooperatives to monetize federal solar and storage tax credits.
Provides the lowest cost resource to AEPCO’s members.
Optimizing Hydropower Allocations
- AEPCO optimizes our members’ hydropower allocations from the Hoover Dam. We bring in this low-cost power from the federal Western Area Power Administration on an aggregate basis, dispatching it to members on an on-demand basis and billing them according to use.
- We work with our scheduling and trading partner, ACES, to dispatch Hoover power hourly.
- We also coordinate Hoover power with power from our Apache Solar I. We have the flexibility to quickly cover loads when solar unit output changes rapidly due to cloud cover or other conditions.
Balancing Renewable Sources Leads to Efficiencies
00:00
(Midnight)
Natural gas and coal generation at Apache Station are dispatched around the clock.
06:00
(6 a.m.)
The Apache Solar Project at Apache Station can generate up to 20 MW of electricity, but only when the sun shines.
18:00
(6 p.m.)
Low-cost hydropower from Hoover Dam is generally available 24/7, but the allocation is limited.
We work with ACES to use the resource when it has the most value—often when it complements solar generation or as a peaking resource to reduce costly power purchases.
In addition to the Apache Solar Project, we’re exploring transmitting wind energy from eastern New Mexico to Apache Station, and we’re analyzing battery technology to make solar and wind generation more cost-effective and reliable.