From Solar Fields to Multifunctional Landscapes: Assessing the Effectiveness of Multifunctional Ground-Mounted PV Systems

The sun offers a boundless supply of clean energy, but capturing it requires space. As nations race to replace fossil fuels with solar power, vast fields of ground-mounted solar panels are springing up across the landscape. This shift brings a familiar tension: the need for electricity clashes with the need to preserve nature and grow food. For years, the debate has centered on whether solar farms destroy habitats or simply occupy land that could be used for something else. Scientists and planners have long tried to measure the efficiency of these installations, asking a simple question: how much power can we get from a specific patch of earth? The standard answer has been to count the energy output per square meter, treating the land as a single-purpose factory for electricity. However, this narrow view misses a crucial possibility. What if a solar field could do more than just generate power? What if it could also support wildlife, grow crops, or restore damaged soil, all at the same time? This concept, known as multifunctional land use, suggests that a single site could serve multiple masters, but measuring its true value has proven difficult. Existing tools often fail to capture the complex reality of a solar farm that is also a meadow or a grazing pasture.

A team of researchers at BOKU University in Vienna set out to solve this measurement problem by looking at real-world solar installations across Austria. They did not rely on computer models or theoretical scenarios; instead, they visited eight specific solar farms that were already operating with dual purposes. These sites ranged from panels built over former landfills to fields where sheep grazed beneath the solar arrays. The researchers interviewed the people who built and managed these sites, took detailed notes on the vegetation, and observed how the land was used. They found that while these multifunctional sites were successful in practice, the standard way of calculating their efficiency was misleading. When they applied the traditional method, which simply divides the total power output by the total area, the multifunctional sites appeared less efficient than a standard solar farm. This is because the panels are spaced further apart to let light reach the grass below, or because some land is dedicated to flower strips rather than electricity generation. The old math suggested these sites were a poor use of land, but the researchers knew this was an incomplete picture. The land was doing more work, just not the kind of work the old formula was designed to count.

To fix this, the team developed a new way of thinking called the Multi Land Use Effectiveness method. Instead of just counting watts, this approach treats the solar farm as a collection of different landscape features, each with its own value. Imagine a solar field not as a single block of metal and glass, but as a patchwork quilt of different elements: some parts are for electricity, some are for sheep grazing, some are for wildflowers, and some are for hedges. The researchers assigned a value to each of these patches based on how much it improved the land compared to its previous state. For instance, if a site previously grew crops with heavy pesticide use, switching to a solar farm with wildflowers and no chemicals was counted as a significant gain for nature. If a site had a fence that blocked animals from crossing, that was counted as a loss. By adding up these gains and losses across the entire site, they could calculate a single score that reflected the total benefit of the land, including both energy and nature.

When they applied this new method to one of their case studies, a solar farm that integrated several different installation types within a single area, the results changed dramatically. This specific site featured a mix of systems, including a standard ground-mounted array, an overhead bifacial system combined with apple cultivation, and a rotational cropping system with tracking PV, alongside dedicated ecological zones. Under the old system, the site looked inefficient because it produced less electricity per hectare than a dense solar farm. Under the new method, the site showed a clear gain. The researchers calculated that the land was effectively doing the work of a larger area. Specifically, the 5.2-hectare site with its mix of solar panels, grazing, and wildflowers provided benefits equivalent to what would have been needed on roughly 7 hectares of land if those functions had been separated into different places. In other words, by combining the uses, the site saved about 1.4 hectares of land that would otherwise have been needed to achieve the same result. This finding suggests that the most efficient use of land is not always the one that packs the most panels into the smallest space, but the one that integrates energy with other vital functions.

The study also highlighted the practical challenges that remain. The researchers found that the construction phase of these solar farms is often the most damaging time for the local ecosystem, with heavy machinery compacting the soil and fencing cutting off animal movement. Even in the best-designed sites, fences were often required by law for safety, which created barriers for wildlife. The team noted that while some operators wanted to remove fences to help animals move freely, regulations often forced them to keep them. However, they also found that simple adjustments, such as leaving gaps under the fences for small animals or planting hedgerows instead of solid barriers, could make a difference. The research confirmed that these multifunctional systems are not just theoretical ideas but are already being built and managed successfully in Austria. The operators reported that integrating sheep grazing or wildflower meadows was not only possible but often improved the site's relationship with the local community and environment.

Ultimately, the paper argues that we need to change how we evaluate solar energy projects. The current focus on maximizing power output per square meter is too limited to guide the future of renewable energy. If we want to expand solar power without destroying nature, we must value the land for everything it can do, not just for the electricity it produces. The new method proposed by the researchers offers a practical tool for planners and policymakers to see the full value of these sites. It shows that renewable energy and biodiversity conservation do not have to be enemies. By using a framework that counts the benefits of nature alongside the benefits of energy, we can design solar farms that are not just power plants, but living landscapes that support the transition to a cleaner future. The study concludes that with the right planning and incentives, these dual-use systems can turn the competition for land into a collaboration, creating spaces that are productive for both people and the planet.