Transforming solar sites from liabilities to assets

There is a saying that the best time to plant a tree was ten years ago, and the second best time to plant a tree is now. A solar developer applies that feeling to the land where his solar projects are installed, demonstrating the power of spreading and maintaining productive green ground cover.

Silicon Ranch established a branch of his company dedicated to regenerative land management practices nearly four years ago and has found that a forward-looking, natural approach to planning solar projects proves fruitful in the long run.

Regenerative Energy, a land management subsidiary of Silicon Ranch, uses sheep in its regenerative land management practices. Silicon Ranch

The goal of Silicon Ranch’s land management subsidiary “Regenerative Energy” was to develop a holistic approach to land preparation and maintenance through practices such as sowing biomimicry of native seed crops and maintaining topsoils. which is often lost when sorting locations.

“We were landowners for seven years and the land we were responsible for was not top of mind,” said Nick de Vries, senior VP of technology and asset management at Silicon Ranch. “It’s not the first thing you think about. You think of module degradation, you think of inverter [preventative maintenance], you think of these other things. Then you realize little by little that there is land here too and we were operationally not good at managing it.”

At the utility level, solar projects can cover hundreds of acres at a time. In regions with natural land cover rather than gravel, this means there is an obligation to maintain the land, especially for solar developers who lease or own the properties on a long-term basis.

“I had seen the solar industry as an obligation to manage their land, but I view land and vegetation as an asset,” said Michael Baute, director of regenerative energy and land management for Silicon Ranch. “We housed a technical asset in the biological asset, and the industry simply looked at that land — at that biological asset — as a liability associated with operational costs.”

Still, re-imagining land management as an asset is not without its challenges. As developers enter new markets with unfamiliar environments, they must learn the new considerations for native plant life, soil quality and precipitation levels.

The first construction rule to create a regenerative solar site is to disturb as little topsoil as possible. De Vries said conventional site preparation practice is to level the land with heavy machinery to flatten the topography for the solar structure. However, the first few feet of soil underfoot are necessary to prevent wind and water erosion and to maintain healthy native vegetation on land.

“We can see the sites that we can move the heaviest, they are the most unmanageable and operationally the most challenging,” de Vries said. “So this isn’t just a ‘hippie feel-good’ thing.”

The topsoil is a nutrient-rich layer of soil capable of supporting plant growth. Rooted vegetation stabilizes the topsoil, which risks eroding when exposed to wind and precipitation. At the solar project level, disruptive topsoil can lead to muddy work areas and stability issues with the array’s structural supports. At an ecological level, the erosion can lead to runoff that can enter nearby waterways and affect the biological makeup of those bodies of water.

Regenerative energy is sowing seeds ahead of the project’s construction, such as this site that now houses Clay Solar Ranch, a 106 MW project in Clay County, Georgia. Silicon Ranch

“On a cable, you have copper, aluminum and a dielectric sheath around it to make sure those dangerous energies can’t get out and electrocute someone,” de Vries said. “The soil needs that same protective layer.”

Maintaining healthy plant life under an array also aids in carbon sequestration. During photosynthesis, plants absorb carbonand when they decompose, that carbon that would have been released into the atmosphere is stored in the soil. By combining native plants with PV modules, both the array and the soil beneath it can reduce carbon.

Studies suggest that new topsoil regenerates of course hundreds of years. It is common in solar energy development to inherit project sites that were formerly used, such as agriculture. That means that in terms of soil quality, developers often “start with a negative bank account,” Baute said.

To address degraded soils and topsoil regeneration, Regenerative Energy collects a seed mix of grasses native to that respective region and reseeds the site. Given the length of the solar energy development process, seeds should ideally be sown at least a year before construction, according to Baute. Newly rooted plants will give the soil stability again.

On-site regenerative practices also consider operations and maintenance, using livestock instead of lawnmowers for landscaping.

“A lot of holistic management is biomimicry, where we mimic the way natural ecosystems have evolved over millions of years,” Baute says. “If we bring sheep onto our land, it honestly sounds a bit esoteric, but we’re mimicking the way bison, wolves and grasslands have evolved together over millions of years.”

Sowing the right plants on site provides many benefits to foraging sheep. The sheep will then fertilize the land and encourage further plant growth, which will create more stable soil and habitats for native animal and insect species. If the sheep eat healthily, they are more likely to reproduce, expanding the herd on that land. And all of the above means less reliance on landscaping equipment and less expenditure on fuel, labor and equipment maintenance.

“We build pastures, we use the impact of animals to improve the ecological health of our farms and ranches. We are not only looking for short term profit. We look at the long term’, says Baute.

Regenerative site practices are not just for site preparation. Regenerative Energy revisits Silicon Ranch solar projects that were installed conventionally to make them regenerative as well. These strategies can be applied at every step of the development, installation and operation process, providing project owners with both environmental and cost benefits.

“For the owner, taking care of your land is the only long-term strategy that works,” says de Vries. “The conventional method will expose it, put you at risk and the cost will only increase over time. So at every stage this is the better way.”

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