September 23, 2021

Solar Energy and Vegetation Selection, Not Just an After-Thought

Solar, Solar Panel, Planning and Landscape Architecture

At first glance, vegetation may not be the first thing that you see when looking at a utility-scale solar project. On the other hand, it might be the only thing you see, as mature buffer plantings can keep views obscured. Whether working on a community solar garden or 100+ MW solar array, choosing the right vegetation can mitigate visibility concerns with adjacent landowners, reduce long-term maintenance, and add to the life of the system. The following considerations can help ensure the long-term success of the project.

1. Vegetative Screening

Geographic Location
Attention to detail regarding species selection is paramount. Emphasis should be placed on native or adaptive species that are acclimated to the climate and environmental conditions. This can promote a quicker establishment and increased survival rates.

The current drought conditions in the U.S. also impact vegetation. Selecting species that are less reliant on supplemental water to become established helps conserve water resources and decrease the potential financial burden of replacement due to plant mortality.

Invasive Species
Try to avoid invasive species when specifying species for vegetative screening buffers. The attributes that allow invasive species to grow rapidly and proliferate also contribute to the cascading negative environmental effects.

Shading
Shading can also have a significant impact on the productivity of solar arrays. When vegetative screening buffers are required near the array, consider the height the plant will be when fully mature. Thinking ahead is important to achieving a balance that will reduce shading impacts while also creating the desired visual screening.

2. Pollinator Scorecards

Solar development revegetation has been a great avenue for implementing pollinator species by states and other regulatory agencies. The goal of the effort is to revitalize pollinator populations across the U.S. Scorecards evaluate projects on several factors, including the total number of diverse species, seed mix areas, and establishment and maintenance practices. If the project hits a certain threshold, it receives accreditation to be called a pollinator-friendly site, which may be a requirement or project goal.

To promote a pollinator-friendly site, try selecting more expensive native pollinator seed mixes with taller forb species on the outside periphery of the project site where no height constraints exist. Under the panels, a low-growing grass-heavy mix is preferred. Carefully plan where you place pollinator mixes. If misplaced, pollinator mixes may require frequent mowing, which could increase maintenance costs and reduce the number of blooming flowers available to pollinators.

3. Bifacial Solar

An emerging and predictably popular trend for solar is the use of bifacial solar modules. Bifacial solar modules increase total energy generation by utilizing both sides of the panels. From a vegetation standpoint, selecting something with a low growing profile can minimize potential shading or interference with sunlight being reflected to the back side of the modules. Selection of species on the ground that have a lighter foliage color can actually contribute to a higher sunlight reflectance as well.

There are many factors to consider when selecting the vegetation for a solar project. With a well-planned plant species selection strategy, you can reduce the financial burden of a project while contributing to healthy pollinator populations. Westwood’s experienced planning and landscape architecture team can create a plan to keep energy output maximized while also revegetating the land to mitigate erosion concerns and improve the pollinator population. Reach out to learn more.

Author 
Nic Meyer, PLA

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