In December 2018, construction began on the Mount Signal 2 solar power station in Calexico, California. Swinerton Renewable Energy, New Energy Solar (NEW), and D. E. Shaw Renewable Investments (DESRI) gathered to break ground on Mount Signal 2, a 200MWdc photovoltaic solar project in Southern California's Imperial Valley. NEW brought Swinerton aboard as its engineering, procurement & construction contractor. Swinerton brought West Coast Aerial Photography, Inc. aboard to document the entire one-year construction of this large-scale solar farm, as documentation via aerial photography has become common with most of Swinerton's ground-mounted solar installations. These aerial images provide a unique perspective on how the construction of a solar farm takes place.
Aerial Photography at Mount Signal Solar Farm
Monthly aerial photography played a crucial role in documenting the construction of the Mount Signal 2 Solar Farm, providing comprehensive visual insights into this large-scale 200MW photovoltaic project. These aerial images captured every stage of development, enabling project developers and construction teams to monitor progress closely, identify potential challenges early, and optimize efficiency throughout the build.
By offering a unique bird’s-eye view, the photography facilitated better coordination among contractors and stakeholders, ensuring the project stayed on schedule and met quality standards. Additionally, this visual documentation served as a powerful tool for showcasing the construction process to utility partners and customers, highlighting the meticulous workmanship and advanced technology driving the Mount Signal 2 solar farm’s success.
Aerial view of Mount Signal 2 Solar Farm in California, a key part of the 794 MW Mount Signal Solar project, one of the largest photovoltaic solar farms in the United States, providing clean, renewable energy to thousands of homes.
Constructing a Solar Farm in Imperial County, California
Mount Signal 2 is a 200MWdc photovoltaic project within the broader 1,200 acre Mount Signal Solar Farm, also known as the Imperial Valley Solar Project, located 6 miles west of Calexico in Imperial County, California. Once tied into the San Diego Gas and Electric high-voltage power lines, Mount Signal 2 is expected to supply energy to power approximately 70,000 homes served by Southern California Edison.
How to Build a Solar Farm in Six Easy Steps
1. Site Selection and Preparation
The area where the solar farm will be installed must be cleared and leveled for solar module installation. Site selection is crucial and should be in large open areas, as any shade reduces output. For mounted systems like the Mount Signal project, structural integrity and load-bearing capacity must be determined, often involving the removal of trees or other vegetation, grading, and adjusting the soil as needed. Additional research is also done to carefully choose low productivity farmland for the solar panel racks, minimizing impacts on valuable agricultural land.
Workers prepare a section of the Mount Signal 2 Solar Farm in Calexico, California, a 200MWdc photovoltaic project generating clean, renewable energy to power over 70,000 homes in Southern California.
2. Installation of Panel Racks
Panel racks must be installed to support the solar panels. Installation is customized for each project site to maximize sunlight exposure while addressing specific needs such as securing the structure against high winds and ensuring waterproofing. These racks are firmly anchored to the ground and constructed from corrosion-resistant materials designed to withstand the harsh weather conditions typical of California’s Imperial County.
In the Northern Hemisphere, fixed solar panel systems are typically oriented toward True South with tilt angles close to the local latitude, often between 30° and 35°, to optimize year-round energy output. However, some large-scale projects like Mount Signal employ advanced tracking technologies that adjust panel positions throughout the day to follow the sun’s path, maximizing energy generation.
3. Wiring and Connections
Electrical wiring is routed from each solar panel in the array to a transformer or connection point on the power grid, enabling the electricity generated to be centralized and distributed for use by the local community.
4. Installation of Panels
Once the panel racks are installed and the wiring connections are complete, the solar panels can be mounted. This involves securely bolting each panel onto its designated rack position and connecting it to the electrical wiring system. The extensive Mount Signal project incorporates over three million photovoltaic modules, mainly utilizing First Solar Series 3 and Series 4 thin-film photovoltaic panels mounted on north-south tracking systems to optimize energy production throughout the day.
Close-up view of solar panels being installed onto mounting racks at the Mount Signal 2 Solar Farm near Calexico, California, showcasing the assembly process of this large-scale photovoltaic project.
5. System Testing
Before being put into service, the solar farm is thoroughly tested for safety and performance. This includes checking all wiring connections, ensuring proper voltage levels, and inspecting each individual panel for any potential defects. Any defects will prevent a solar panel's ability to absorb energy from the sun, impacting how much electricity the solar farm produces.
6. Connection to the Grid
Once the construction of the solar farm is finished, with all solar panels installed and properly tested, the final step is to connect it to the electric grid. This step allows the energy generated at the solar power station to be brought into the wholesale electricity market.
Aerial view of the completed Mount Signal 2 Solar Farm in operation in Imperial County, California.
Positive Impacts on the Local Community
The Mount Signal 2 solar project has brought significant positive impacts to the local community beyond providing clean, renewable energy. In a region like Imperial County, where unemployment rates have historically been among the highest in the nation (currently estimated at 17%) the project created over 200 local jobs during construction, offering much-needed employment opportunities to area residents. These jobs not only supported families but also helped stimulate the local economy.
The benefits extend beyond construction, as ongoing operations require regular maintenance, including cleaning solar panels, inspecting wiring and connections, and replacing any worn or defective components. This continued need for skilled labor ensures sustained employment opportunities in the region.
Moreover, the project has garnered broad support from environmental groups such as the Sierra Club and Audubon California, highlighting a shared commitment to wildlife preservation alongside clean energy goals. By mitigating approximately 356,000 tons of carbon dioxide emissions annually, equivalent to the carbon offset provided by 15 million trees each year, the Mount Signal 2 project contributes to a healthier environment, enhancing the quality of life for the local community and setting a model for sustainable development.
Aerial view of the Mount Signal 2 Solar Farm near completion in Calexico, California, which continues to provide ongoing employment opportunities through maintenance and electrical work, supporting local families and driving sustainable economic growth in the region.
The Benefits of Renewable Energy
Utility-scale solar farms like Mount Signal 2 not only provide clean energy for Californians but also create jobs for the local workers who help to build and maintain them. The broader Mount Signal Solar Farm produces about 1.29 billion kWh annually, powering roughly 192,000 homes, and mitigating around 850,000 tons of carbon emissions each year.
The Mount Signal project represented a significant investment, with a total cost of approximately $1.1 billion. Financing was secured through two main tranches: a $416 million long-term institutional tranche led by Morgan Stanley & Co and Citigroup Global Markets, and a $220 million cash-grant loan from Morgan Stanley Senior Funding and Citibank. Although costly, this investment is vital for advancing sustainable, green infrastructure. Projects like the Mount Signal solar farm are essential steps toward building more resilient, eco-friendly cities and communities capable of withstanding increasingly severe weather events.
The Mount Signal 2 Solar Farm near Calexico, California, boasts a capacity factor of 29.7%, reflecting its efficient energy production, and exemplifies the ongoing innovation in the solar industry by combining large-scale solar arrays with advanced technology to drive sustainable solar generation for the future.
The Mount Signal solar farm stands as a landmark achievement in renewable energy development, showcasing the integration of advanced solar technologies, meticulous construction processes, and strong community and environmental support. Spanning three phases and utilizing innovative tracking systems and thin-film photovoltaic modules, the project not only generates clean, sustainable power for hundreds of thousands of homes but also contributes significantly to carbon emissions reduction. With substantial investment and collaboration among industry leaders, environmental groups, and local stakeholders, Mount Signal exemplifies how large-scale solar projects can drive economic growth, job creation, and environmental stewardship. As the solar industry continues to innovate, projects like Mount Signal pave the way for a cleaner, more resilient energy future.