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Mark Walling, vice president of engineering for Coastal Electric Cooperative in Walterboro, routinely gives tours of the Colleton Solar Farm. “It certainly has generated a good bit of interest,” he says.
Photo by Mic Smith
Those who live close by weren’t sure what to think when they heard about a new neighbor moving into the area. In the fall of 2013, residents learned Walterboro was going to be the home of South Carolina’s largest solar farm.
“All I knew was the best dove field for miles around was going to disappear,” recalls Jim Floyd, who lives across the street from the farm. “This was a favorite hunting spot.”
In a 15-acre field adjacent to Interstate 95, hunters gave way to construction crews as an army of solar panels rose. Completed ahead of schedule on Dec. 20, 2013, the project by then had a name—the Colleton Solar Farm. Rows of gleaming glass panels, 10,010 of them, began converting the sun’s energy into utility-scale power.
And the reaction today of the residents who live close to the farm? Floyd shrugs. “I hardly give it a notice anymore, to tell you the truth.”
Performance better than expected
The Colleton Solar Farm is a collaborative project among solar contractors TIG Sun Energy of North Charleston, Santee Cooper, and the state’s not-for-profit electric cooperatives. TIG Sun Energy owns the farm. Santee Cooper and the co-ops purchase the energy the farm produces and distribute it to homes and businesses.
Designed as a “commercial laboratory” to explore the viability of solar power in South Carolina, the farm is beginning to supply useful data as well as clean energy, says Grant Reeves, senior vice president of TIG Sun Energy.
In the first full year of operation, the Colleton Solar Farm generated 5 percent more electricity than predicted—enough extra energy to power 200 homes for a full month, he says.
Of the 10,010 solar panels on the farm, 60 percent are fixed, positioned facing south, to capture as much of the sun’s energy as possible. The remaining solar panels have tracking capability, meaning they move slowly throughout the day to follow the sun.
Analysis to date indicates tracking panels generate power for about 3½ hours longer per day during the peak summer months. As a result, electricity produced by the tracking panels costs 9 percent less per kilowatt-hour than the panels that are stationary.
“The tracking panels are more expensive on the front end,” says Reeves. “But it looks like they pay for themselves because of their productivity.”
Learning how to squeeze every bit of energy from the solar farm is an important part of the project. With today’s solar technology, electricity produced from the sun is more expensive than electricity produced from conventional sources of power, such as coal and natural gas. For utility providers charged with providing affordable electricity to the consumers they serve, the cost of solar is an obstacle.
Reeves predicts that as the price of photovoltaic panels falls—and as manufacturers increase the efficiency of their products—solar power will become a more cost-effective source of electricity.
“I think the farm has shown that solar has a place in the market,” he says.
Generating interest
When he arrives to unlock the front gate at the solar farm, Mark Walling nods toward the compound and says, “It’s impressive looking, isn’t it?”
As the vice president of engineering for Coastal Electric Cooperative in Walterboro, Walling has given dozens of tours of the solar farm.
“It certainly has generated a good bit of interest,” he says. “I think most people are surprised to see how many panels it takes to generate the amount of electricity it does.”
The panels dominate the landscape at the solar farm. Each panel is grouped with three others to form a rectangular “solar array,” and each array covers an area the size of a small room. When the sun is at its peak on a cloudless day, the farm’s panels can generate up to three megawatts of electricity, which is enough energy to power 300 average-size homes.
“You are talking about a good-sized neighborhood,” Walling says. “However, look how much space it requires to make that happen. The technology works. But you have to wonder how many open spaces we have like this in the state.”
Coastal Electric crews monitor and maintain the interconnection lines and equipment, and so far, the facility has experienced few technical or maintenance issues. It survived Winter Storm Pax in February 2014 without damage, but multiple days of rainy weather last fall highlighted a concern utilities have about the intermittent nature of solar energy.
When the sun isn’t shining, the farm does not produce energy. That’s “not a huge problem if you’re talking about an afternoon thunderstorm,” Walling says. Encounter long stretches of rainy weather, however, and the solar farm sits idle, and the power consumers rely on must be generated by other means.
“If we had to rely solely on the farm to deliver power, you can see how that would be an issue,” he says.
Reeves and other solar advocates point to emerging technologies in battery storage as the key to making solar a reliable source of electricity. If a new generation of batteries can store large amounts of energy for use when the sun isn’t shining, “a solar farm looks a lot more practical for the utilities,” he says.
The solar farm continues to provide valuable data about the costs and reliability of utility-scale solar power. Collecting that information was one of the driving forces behind the project, says Mark Svrcek, chief operating officer and senior vice president of corporate strategy at Central Electric Cooperative.
Central Electric, the organization that supplies wholesale power to all 20 of the state’s electric cooperatives, will continue to monitor and study the farm as a practical source of electricity. Svrcek says interest in renewable sources of power will grow as utilities grapple with federal regulations calling for a reduction in carbon-dioxide emissions from traditional power plants.
While solar—as it works today—may not be ready for prime time, Svrcek says, “I think it’s safe to say we are moving into a period when this carbon-free resource becomes a more significant part of utilities’ portfolios.”
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Colleton Solar Farm by the numbers
- 10,010: The number of solar panels that produce electricity
- 3: megawatts of electricity produced when the sun is at its peak in the sky.
- 300: number of homes powered by 3 megawatts of electricity
- 4,687: number of megawatt-hours generated in year one of operation
- 30,356: 60-watt lightbulbs powered for 8 hours a day
- 3,818: tons of carbon dioxide saved from power generated at the farm
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Get More
See the solar farm in action – Click here to see how much electricity the Colleton Solar Farm is generating right now.
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A solar farm comes alive – Watch the time-lapse video of the Colleton Solar Farm under construction.