Examining the ecological trends in UK solar farms

Clean and renewable solar energy is a practical and viable solution against climate change, a ray of hope for a warming planet. But every silver lining has a cloud.

While solar farms create jobs and remove more CO2 than trees, they can also cast a shadow on the environment. Poorly designed PV fields can disrupt wildlife habitats and reduce plant diversity. Suboptimal installations can also affect surface albedo and subtly shift local temperature, humidity, and rainfall patterns, causing unintended ecological side effects.

So, how can we harness the sun without harming the planet? According to Solar Energy UK, the first step is to measure precisely how PV farms impact local ecosystems using systematic biodiversity tracking.

In this vein, the trade association partnered with consultancy firm Clarkson & Woods, Lancaster University, and Wychwood Biodiversity to publish a standardized ecological monitoring approach for solar farms. Their pilot study gathered comparable data across 87 UK solar sites to show how PV farms affect local flora and fauna. It also lays out metrics to measure these impacts. Let’s take a closer look. 

How are solar farms impacting the environment?

Vegetation management can improve plant and animal populations around PV installations, allowing solar farms to support biodiversity preservation and natural restoration across the UK. Here are some of the most interesting themes and insights from the report:

Botany

Researchers placed 1,504 quadrats directly beneath PV panels, between rows of panels, and outside the fenced-in panel areas to monitor and catalog the types of vegetation growing in different environments within the participating solar farms.

They found a remarkable diversity of plant species: 59 types of grasses (graminoids), 211 broadleaf plants, and 28 other plant types, such as woody plants and climbers. Yorkshire fog grass was the most abundant species, found in over 50% of the quadrats. Hardy plants, particularly wildflowers and native grasses, provide essential habitat and food sources for pollinators maintaining this thriving botanical community.

Weeds

Found in 82% of solar farms and 22% of all surveyed areas, injurious weeds such as common ragwort, broad-leaved dock, curled dock, creeping thistle, and spear thistle need to be managed so they don’t spread to neighboring agricultural lands. When contained, they can coexist with other plants and provide resources for bees, butterflies, and moths.

Planting plugs and bulbs of robust, shade-tolerant wildflowers and ferns is a good way to keep harmful weeds in check, according to a NextEnergy Solar Fund case study. This creates a dense weed-suppressing ground cover that maintains a healthy ecosystem under the solar panels. 

Invertebrates

Researchers found at least 47 species and over 3,000 individual insects across surveyed sites, including butterflies, bumblebees, moths, dragonflies, and various bees. They also found that farm margins and meadows harbored more variety and more insects overall compared to areas between solar panels. The meadow brown butterfly was the most common, but rare species like Norfolk hawkers and scarce chaser dragonflies were also observed.

Birds

The report identified over 90 bird species across participating solar farms. Notably, the British Trust for Ornithology lists 21 of these species as Red (endangered) and 25 as Amber (of medium conservation concern).

Solar farms with rich plant and invertebrate life tend to attract a wider range of avian life. The report identified nearly 8,000 birds across these sites, each hosting 25 species on average, with some sites reaching as high as 47. Interestingly, solar power plants are also becoming important feeding grounds for skylarks. Ground-nesting birds like oystercatchers and meadow pipits also inhabit these farms, with some displaying breeding behaviors.

Mammals

Despite this, many species, especially smaller ones, are elusive. Researchers are turning to advanced methods like environmental DNA analysis to understand better how these mammal populations interact with PV installations. Researchers analyze DNA fragments found in the environment to detect hard-to-spot small mammals and amphibians and get a clearer picture of biodiversity.

Can solar farms support biodiversity?

Solar Energy UK’s report confirms that a well-designed and properly managed solar farm can be a nature reserve throughout its operational life. Rows of tilted panels and open spaces create an interplay of sun and shade, resulting in unique microhabitats for plants and animals. 

Land managers can make the most of this distinct environment to boost biodiversity net gains and minimize their solar farm’s impacts by:

• Planting native hedgerows and establishing field margins using wildflowers or grasses to create food sources, nesting, and shelter sites for birds, insects, and small mammals.

• Constructing natural ponds and using displaced construction soil to form bunds (raised banks or mounds) that promote shrub and scrub growth, reduce nutrient runoff into nearby water bodies, and create favorable conditions for developing species-rich grasslands.

• Using the cooler soil temperatures under solar panels to encourage plant diversity and provide comfort for grazing animals during warmer months.

• Installing panels high enough to allow crop growth underneath, and as such creating shaded environments that reduce water evaporation and optimize growing conditions for certain types of vegetation.

• Collaborating with conservation organizations early in the planning stages to make biodiversity a core component of solar farm designs. 

On a system-wide level, the solar industry needs a standardized system for analyzing interactions between land management, solar panels, and wildlife over time. Solar Energy UK’s monitoring guidance and the Biodiversity Net Gain (BNG) mandate provide this framework. 

BNG requires developers to monitor and manage their solar sites for 30 years, a long-term perspective that aligns well with the typical 25- to 30-year lifespan of PV panels. With dedicated oversight and adaptive management, solar developers and land managers can actively support biodiversity and sustainable land use.