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Scientific Reports volume 15, Article number: 30287 (2025) Cite this article
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Solar energy expansion often comes at the cost of forest destruction, creating fundamental conflicts between renewable energy goals and ecosystem preservation. Here, we demonstrate that solar trees could enhance power generation capacity while preserving coastal forest landscapes. Our quantitative comparison reveals that linear arrangements of these structures achieve superior power capacity compared to conventional fixed panels while preserving existing forest cover. Through 3D geospatial simulations and standard test conditions, we show that linear arrangements of solar tree structures preserve 99% of forest cover, whereas conventional fixed panel installations require eliminating 98% of forest cover while achieving equivalent power generation capacity. Although our study centers in South Korea, the methodology has broad applicability for other nations looking to expand renewable energy while preserving forest ecosystems. The first thorough quantitative model to compare the installation of solar trees to conventional ground-mounted panels in coastal forest areas is presented in this study. By providing a strategic route for densely populated nations to meet ambitious energy targets without jeopardizing forest carbon reservoirs, the study directly supports the objectives outlined in the COP28 Global Renewables Pledge and the Glasgow Leaders’ Declaration on Forests. Solar trees are a promising dual-solution to align energy and environmental priorities as global commitments call for the tripling of renewable capacity by 2030 while maintaining forest preservation pledges.
The global movement towards renewable energy is gaining traction and major economies are setting high objectives. The European Union set to use its electricity supply fully renewable by 2050, while Chinese government plans to achieve carbon neutrality before 2060 with setting significant milestones by 2050^1,2. The shift gained more momentum at COP26 and COP28, where world leaders reported their commitments to phase out coal power and transitioning away from fossil fuel, the era of carbon neutrality is beginning³. “Carbon neutrality” means a condition wherein greenhouse gas emissions are balanced by natural or engineered uptake by global carbon sinks, such as forests⁴. In the path to carbon neutrality, countries must drastically reduce the use of fossil fuels as a source of greenhouse gas emission.
Solar energy yields significantly higher power output per unit area compared to other renewable sources, including wind and bioenergy⁵. Solar power is projected to become the most cost-effective energy technology across most global regions⁶. Amid accelerating technological advancements and a significant reduction in production costs, solar power is increasingly positioned to become a leading substitute for coal-based energy in the near future. Thus, solar energy is not an option but a necessity to achieve carbon neutrality. However, the profound loss or fundamental devastation of natural ecosystems occurs worldwide because flat fixed solar panels completely remove forest cover, thus reducing the carbon sinks at project sites^7,8. In South Korea, solar power plant expansion in mountainous regions led to increasing annual deforestation rates: 529 hectares in 2016, 1,435 hectares in 2017, and 2,443 hectares in 2018⁹. Removing mature forest cover has triggered widespread soil erosion and landslides near solar installations.
Solar trees combine photovoltaic power generation with forest carbon sequestration. These structures mimic natural tree morphology with solar panel arrays as branches and leaves^10,11. The vertical design enables photovoltaic generation in the upper canopy while allowing sufficient light penetration to preserve understory vegetation¹². Previous studies evaluated individual solar tree performance using point-specific environmental parameters, including wind speed, temperature, and solar radiation^13,14,15. Energy output from individual units shows high temporal variability due to changing solar angles and weather conditions. However, single-unit performance metrics inadequately predict area-wide generation capacity compared to conventional solar installations¹³. This may lead to a misinterpretation of the overall energy production of the solar power plant when it is assessed solely based on the performance of individual solar trees. While conventional solar installations typically operate with thousands of modules, solar trees lack standardized protocols for energy production assessment. This gap creates uncertainty in evaluating their area-wide installation capacity relative to traditional flat-panel arrays.
Estimating the energy-generating potential of solar power plants is an important step in determining photovoltaic project viability. This is because the projected power output from installed solar panels serves as the foundation for assessing the economic feasibility of solar power plants. However, solar energy generation is highly variable, influenced by environmental factors such as solar radiation, temperature, and wind conditions. Previous studies have measured energy acquisition efficiency in power plants based on collector area (square meters or square feet) rather than installed capacity for energy production¹¹. As a result, solar trees were not easily comparable to flat fixed solar panels and were often excluded from relevant statistics, depending on whether they were commercially available or existed only as prototypes developed by individual researchers¹⁶. The installation capacity of solar power plants enables quantitative comparison between solar trees and traditional flat fixed panels, even if the operating time or location of the power plant is different. The Maximum power output(W) per module is calculated under globally standardized test conditions (Standard Test Conditions, STC¹⁷). This allows for a direct comparison of installation capacity between traditional flat panels and solar trees under standardized conditions, independent of external factors such as location, solar irradiance, temperature, and weather. STC creates a uniform test framework, facilitating standardized evaluations of photovoltaic modules across manufacturers. Quantitative evidence can be provided to compare the spatial efficiency of solar trees against traditional panels through installation capacity analysis.
Previous studies have offered valuable insights into the performance of individual solar trees¹⁸. However, a significant gap remains in evaluating the feasibility of large-scale deployment in real-world mountainous terrains. Among the limited existing research, one study most closely aligned with the present work demonstrated the potential for installing solar trees in mountainous areas, highlighting their applicability in such challenging environments¹⁹. Coastal forests are vegetation communities established under salty winds on the coast, and their composition and structure are different from forests concentrated in the mountains on land. They prevent disaster by blocking strong winds, salinity, tsunamis, and fog. Coastal forests play multifaceted functions such as noise prevention, biodiversity conservation, natural scenery, health and recreation area and surface run-off prevention. Here, this study aims to evaluate the installation capacity between simulated solar trees and flat fixed panels in coastal forest landscapes. Using satellite images from Google Earth, captured both before and following the construction of the solar power plant, we examine flat fixed panels against simulated solar trees to compare their area-specific installation capacities.
The study area (YoungJin solar power plant in Goseong county, South Korea), Pléiades satellite imagery taken in November 2021. Inset: The asterisk (*) indicates the location of the study area within South Korea. The red polygon delineates the boundary of the solar power plant selected as the experimental site for this study. The letter S shows the photovoltaic power plants that have rapidly proliferated throughout the study area in the last decade. A three-dimensional view of the highlighted area is shown in Figs. 2 and 3, while a two-dimensional view is presented in Fig. 4.
The satellite imagery was obtained from Google Earth Pro 7.3.6 (https://www.google.com/earth/versions/#earth-pro). The map was created in Google Earth Pro 7.3.6 and Adobe Photoshop CS3 (https://adobe-photoshop-cs3-update.en.sofonic.com/).
The study area is located in Yeochun-ri, Ganseong-eup, Goseong County, Gangwon Province, South Korea, spanning from 128°39’83″ to 128°39’99″ E longitude and 38°36’13″ to 38°35’91″ N latitude. The site is characterized by gently sloping hilly terrain (inclines less than 25º) and reaches a maximum elevation of 271 m (Fig. 1; Table 1). Forests around the coast of South Korea have recently experienced serious damage due to solar power plants. The green area occupied by the coastal forest was transformed from natural forest cover into an industrialized landscape dominated by black solar panels. The surrounding artificial structures built along with the solar power plant transformed the coastal green scenery into a landscape completely covered with cement concrete. Landslides frequently occur due to soil loss in areas where coastal forests have disappeared. Soil run-off from deforested areas also caused serious pollution problems in rivers, streams, coastal lagoons, beaches and oceans. Spaces covered with black solar panels have transformed habitats into places where living things cannot survive, completely destroying the biodiversity of the forest ecosystem²¹. Despite their promotion as an environmentally friendly ‘chimneyless industry,’ solar power installations in coastal forests have created significant environmental challenges.
Goseong County, where the study area is situated, is a local government located in the northernmost part of South Korea. In the Korean War armistice agreement after the Korean War, Goseong County was divided into South and North Korea. Thus, there are two Goseong counties in the Korean Peninsula, one in South Korea (664.55 km²) and one in North Korea (518.56 km²). It is located near the Korean Demilitarized Zone (DMZ) and Civilian Control Zone (CCZ), a relatively untouched area where land-use activities have been heavily regulated since the Korean War Armistice. Goseong DMZ is a place that symbolizes the tragic history of divided Korea, lasting for more than six decades. It is located in the foothills of Mt. Geumgang, which is known to Korean people as the most sacred and beautiful mountain in the Korean Peninsula. The summit in Goseong County is the first peak among the 12,000 peaks of Mt. Geumgang. The solar power plant was developed by clearing a section of the mountain ridge located at the first peak of Mt. Geumgang. Most of the mountains located at the foot of Mt. Geumgang in the study area have problems such as landslides and soil loss due to artificial structures built by solar power plants, as shown in Fig. 1.
In the midst of military confrontation, the residents of Goseong always experienced war-related anxiety and endured the pain of being excluded from development. Goseong, which is located at the starting point of Mt. Kumgang tourism, once emerged as a center of inter-Korean exchange and cooperation. Mt. Geumgang tourism brought significant changes to the quiet town of Goseong. Land prices rose sharply due to investments from outsiders, including the metropolitan area. The commercial districts of Goseong, which had depended on Mt. Kumgang tourism, retreated into underdeveloped villages again due to the abrupt cessation of tourism. Goseong residents now hope that the construction and installation of a solar photovoltaic power plant in the region will provide an opportunity for a regional revitalization comparable to the previous Mt. Geumgang tourism boom. Consequently, small-scale solar power plants are concentrated in this study area as high land prices in the Seoul metropolitan area make it difficult to install such facilities there.
Establishing fundamental data is essential for evaluating solar trees in terms of installation capacity. The simulation provides a foundational reference for conducting comparative analyses of the experimental site before and after the construction of the solar power plant. Google Earth serves as a representative data source for tracking changes in the coastal forestry landscape prior to development. It offers high-resolution satellite imagery in both 2D and 3D formats, capturing conditions before and after solar power plant construction. For this study area, high-resolution imagery is available from DigitalGlobe and Airbus²²including QuickBird (65 cm resolution) and Pléiades (50 cm resolution). The images used in the study consist of fused images provided by Google Earth, generated through the combination of panchromatic and multispectral imagery²³. Google Earth provides free access to image downloads for research purposes, while restricting large-scale downloads intended for commercial use. The latest satellite imagery serviced for the study area by Google Earth was captured in November 2021. The most recent imagery predating the flat fixed plant construction was taken in April 2012.
In order to model the influence of a solar tree on its surroundings, it is essential to utilize three-dimensional satellite imagery with high spatial resolution captured both prior to and following the construction of a solar power facility. One key benefit of employing Google Earth as a data source is its ability to provide access to such imagery across different time periods at no financial cost. Previous studies using Google Earth reported local applications for specific targets, such as solar power plants that require high-resolution images²¹. Three-dimensional imagery available through Google Earth may vary depending on the angle and position from which the scene is observed. A significant gap remains in current research concerning the simulation of solar tree installations using Google Earth’s 3D imagery obtained before and after the development of solar power plants, especially when viewed from a fixed observer perspective. In order to improve both visual realism and spatial consistency in these simulations, it is important to model solar trees at a consistent scale and apply standardized spacing that accurately reflects their real-world placement. In this study, Google Earth 3D imagery was employed to incorporate realistic dimensions and spacing of solar trees based on ground-level perspectives. Hanwha Q CELLS Korea installed a 4.8 by 4.1 m solar tree in front of the National Assembly Building in Seoul on August 31, 2017. This installation captures solar energy during daylight hours and uses stored electricity to power LED illumination at night²⁴. Photomontage techniques were applied to convey the spatial impact of solar tree deployment within the study area, using Adobe Photoshop in conjunction with 3D terrain modeling. The photomontage is a widely accepted method in academic and professional contexts for visualizing proposed landscape modifications, particularly in the fields of environmental planning and design²⁵. The solar tree structure at the National Assembly site was digitally integrated into the geospatial context to generate before-and-after imagery that accurately conveys the extent of landscape transformation.
To position the simulated solar trees at regular intervals within the 3D landscape, slope distances were measured using the elevation profile tool available in Google Earth’s path measurement function. A uniform spacing of 20 m was applied across the terrain to reflect realistic deployment conditions. Topographical measurements were taken at systematic 20-meter intervals using Google Earth’s elevation path functionality for precise spatial positioning within the simulation environment. In remote sensing, interpreting spatial features involves quantitatively analyzing image-based data tailored to specific user objectives. This study evaluated changes in the coastal forest landscape by measuring three distinct landscape elements (forest coverage, solar panel installations, and unoccupied terrain) using the polygon measurement tool within Google Earth Pro’s interface. This allowed for a quantitative assessment of land cover changes before and after the installation of solar trees. This remote sensing methodology facilitated quantitative information extraction aligned with specific analytical objectives. Specifically, three distinct landscape elements within the study region were visually identified based on consistent spectral and spatial characteristics such as canopy texture, color, and shadow patterns. This approach enabled a comprehensive assessment of the coastal forest ecosystem modifications from solar tree implementation. This method has been widely applied in prior studies for land cover classification and vegetation mapping using Google Earth²⁶.
Depending on the development progress, solar trees can be divided into three stages: trial construction at the living lab level, installation as a promotional product, and profit generation through energy sales in a solar power plant. The solar energy industry earns revenue by supplying electricity generated from solar power plants to the national grid. It is estimated that no solar tree manufacturing company in the world is reaching the level of selling the generated electricity. Currently, the companies that install solar trees do not manufacture solar modules. Reports indicate that there is no solar tree manufacturer among the world’s top 10 solar panel manufacturers²⁷. In verifying the area-wide installation capacity of the solar trees, comparing many solar trees with various designs and performances helps secure the reliability of evaluation results. This is because the evaluation result differs depending on which solar tree is applied. No previous studies have identified products specifically suited for large-scale deployment comparisons between solar trees and conventional photovoltaic systems. Because solar trees are designed to replicate the branching structure of natural trees, their energy output can vary considerably, depending on the number and configuration of these structural elements. Since solar trees are sold with differentiated capacities according to locations such as zoos, museums, airports, and parks, reflecting customer demand, a comprehensive comparison of traditional methods across all commercially available solar trees is unfeasible.
The selection of appropriate evaluation criteria is a critical initial step in comparing solar trees with conventional photovoltaic panels. The installation capacity of a solar power plant refers to the maximum amount of electricity that the system is capable of producing under optimal conditions. According to the U.S. Energy Information Administration (EIA), capacity denotes the peak electrical output a generator can achieve under ideal circumstances. In contrast, electricity generation refers to the actual amount of electricity produced over a specified time. In contrast, electricity generation refers to the actual amount of electricity produced over a specified time period²⁸. For example, when the installed capacity of the system is 1 MW, it indicates the maximum power output, that can be obtained at an ‘instant’.
However, the solar plant operating at the maximum capacity of 1 MW will not be able to continuously produce 1 MW of power. Power is measured in kilowatts or megawatts (kW or MW). Energy, which is the power over a period of time, is measured in kilowatt-hours or megawatt-hours (kWh or MWh). The total amount of energy that a solar power system can produce is influenced not only by its capacity but also by the duration of its operation. Installation capacity is primarily determined by the number of solar modules installed, as each module contributes to the overall potential output. Like traditional solar power plants, solar trees are equipped with conventional photovoltaic panels. Notably, solar modules represent the most significant cost component in constructing solar power facilities. Most manufacturers and certification bodies rely on Standard Test Conditions (STC), an industry-wide benchmark to evaluate module performance. STC provides a standardized basis for comparing the output of PV modules, simulating ideal conditions with an irradiance of 1000 W/m², a cell temperature of 25 °C, and an air mass of 1.5¹⁷. The maximum power indicated according to the STC was selected as the criterion for comparative evaluation between solar trees and the traditional flat fixed panel.
The Council of Scientific & Industrial Research (CSIR) in India has highlighted that the CSIR–Central Mechanical Engineering Research Institute (CMERI) has developed what is claimed to be the world’s largest solar tree¹⁶. This promotional material for this solar tree provides detailed specifications (maximum power per panel: 330 W, number of panels mounted on a solar tree: 35, the installation capacity of the solar tree: 11.5 kW) on the panel mounted on the solar tree. For the purposes of this study, it is assumed that solar trees installed in the designated study area share the same specifications as those developed by CSIR—specifically, 35 solar panels with a combined capacity of 11.5 kW and a surface footprint optimized for minimal land use²⁹. It was assessed whether it is possible to achieve a similar installation capacity to the traditional method. EcoWatch, a grassroots news outlet with a digital readership exceeding two million monthly visitors, has published a list of the top 10 solar panels, ranked according to criteria such as efficiency, durability, warranty, cost, and temperature coefficient. This ranking was referenced in the selection of photovoltaic modules considered for comparative evaluation in this study, ensuring that the analysis reflects panels commonly recognized for high performance and market relevance²⁷. It is assumed that the solar panel evaluated with the highest ranking by EcoWatch³⁰ is mounted on a solar tree manufactured by CSIR of India (Table 2).
The solar tree simulated using 3D Google Earth imagery captured prior to installing flat fixed solar panels, based on QuickBird satellite imagery dated April 2012 (see Fig. 1 for image location). (a) The simulated placement of solar trees within a coastal forest area damaged following the construction of the flat fixed solar plant. (b) a simulation along an adjacent hiking trail, with a slope distance of approximately 460 m. In this scenario, 97 solar trees were positioned according to a spacing criterion of one tree every 20 m. The reddish polygon delineates the section of coastal forest impacted by the flat panel installation. A scale bar was not included, as horizontal and vertical scales vary with the observer’s viewpoint in 3D satellite renderings.
The satellite imagery was obtained from Google Earth Pro 7.3.6 (https://www.google.com/earth/versions/#earth-pro). The map was created in Google Earth Pro 7.3.6 and Adobe Photoshop CS3 (https://adobe-photoshop-cs3-update.en.sofonic.com/).
The most critical step in simulating solar trees is identifying installation points within a defined area based on predetermined spatial criteria. No existing studies have systematically examined quantifiable indicators—such as separation distance and precise installation locations—when simulating solar tree placement using Google Earth imagery. The standard arrangement method for solar power plants is an area-based project that places solar panels intensively in a specific place. The area-based project transforms the coastal forest landscape into a gray land cover where only solar panels and cement concrete remain. It is not possible to conserve forest carbon and secure solar energy simultaneously. In the area-based development project, the only option is the complete destruction of the ecosystem. A solar power plant is a long-term business that stably produces electricity and secures profits for more than 20 years. If a solar power plant is not properly maintained, even if the design and construction are well completed, the energy production efficiency will drop sharply, affecting the profit. If a module is contaminated by fallen leaves, dust, bird droppings, or snow, the amount of sunlight it can absorb decreases, leading to reduced power generation. Furthermore, since multiple cells are connected, there is a high possibility that the solar panel will not work if an individual cell fails due to contamination. Arranging the solar tree linearly to secure a working space and to prevent cell contamination can overcome the damage caused by the area-based arrangement. A mountain hiking trail—rather than a vehicular road—has been constructed in the study area. The surrounding landscape is fragmented due to prior human activities, making the vicinity of the trail a particularly suitable site for solar tree installation. Thus, solar trees were installed along the study area boundary and hiking trails, as shown in Fig. 2.
Every solar power project presents unique engineering and environmental challenges, which are influenced by factors such as the size of the solar tree’s steel trunk and site-specific characteristics, including topography, drainage, soil composition, vegetation, and the timing of construction activities. Among these, the most critical variable is the separation distance between solar tree installation points, as it directly determines the spatial extent of environmental disturbance during construction. This distance can vary depending on the topographical features of the site, and analyzing different forest landscapes can help assess the influence of spacing on ecological impact. Given the complexity of variables such as elevation, slope, aspect, forest cover, and solar radiation, it is nearly impossible to simulate solar tree placement while simultaneously accounting for all influencing factors. When scaled accurately within the 3D imagery, a solar tree measuring 4.8 × 4.1 m allows for substantial deployment across the study area, which covers approximately 22,856 m². For example, visual clarity was diminished along a 460-meter section of the hiking trail (Fig. 2b) when too many solar trees were placed in a limited space. A spacing interval of one tree per 20 m was adopted to enhance interpretability and avoid unrealistic visual compression. This configuration allowed for a realistic representation in the simulation and illustrated that separation distances can minimize ecological disturbance. As shown in Fig. 2, this spacing strategy effectively demonstrates that solar trees can be integrated into the coastal forest landscape without causing substantial ecological disruption.
Three-dimensional Google Earth satellite imagery illustrating the degraded coastal forest landscape following the installation of flat solar panels. The reddish polygon delineates the boundary of the solar power plant. See Fig. 1 for the location of the image. * shows the evidence that the coastal forest landscape surrounding the solar power plant was extensively damaged during construction. Seven years after the completion of the construction, it remains in an unrestored state.
The satellite imagery was obtained from Google Earth Pro 7.3.6 (https://www.google.com/earth/versions/#earth-pro). The map was created in Google Earth Pro 7.3.6 and Adobe Photoshop CS3 (https://adobe-photoshop-cs3-update.en.sofonic.com/).
However, Fig. 3 shows that the photovoltaic power plant significantly damages the coastal forest cover outside the power plant boundary. Since the solar power plant construction project was completed in 2014, the forest landscape damaged during the construction period should be restored to its original state. As specified in the Environmental Impact Statement²⁰the construction was carried out here by cutting the slopes. During the construction process, the surrounding forest cover was damaged due to the operation of excavating machines. The damaged coastal forest was left unattended seven years after the completion of the construction. To facilitate a quantitative comparison of installed capacity before and after the construction of the solar power plant, a total of 97 simulated solar trees were installed strictly within the boundary of the solar facility. This constraint ensured that the simulation reflected only the designated development area. However, if installations were extended into adjacent zones where the coastal forest landscape has already been degraded, a substantially greater number of solar trees could be accommodated. Considering the damaged coastal forest cover around the power plant, the impact of solar trees on the coastal forest landscape demonstrates greater benefits than the level presented quantitatively in this study (Table 2).
The result of this study provides quantitative evidence that the traditional method requires a much larger space compared to solar trees because it installs solar panels while completely destroying the coastal forest cover. This study confirms that the same installation capacity as the traditional flat fixed panel can be achieved, even if only 63 solar trees are installed, although the 97 solar trees can be arranged in the experimental target (Table 3). The power generation performance of solar panels is developing at a tremendous rate. The LG Mono X^® Plus 450 W panel delivers nearly twice the output of the 230 W solar panels installed in the study area in 2014, highlighting the significant advancements in photovoltaic efficiency over the past decade. As the power generation performance of the panel improves, the solar tree will be able to secure better installation capacity than the traditional method while occupying a smaller area. LG Mono X^® Plus 450 W panels are a similar physical size to the 330 W panels utilized in the solar tree manufactured by the Council of Scientific & Industrial Research (CSIR), India. This means the LG Mono X^® Plus 450 W offers more electricity per square meter than the 330 W panel.
Comparison of coastal forestry cover between solar trees and flat fixed panel installation, (a) coastal forestry landscape before solar power plant construction, (b) non-forestry landscape after flat fixed panel construction. See Fig. 1 for the location of the image.
Time series images (2012 and 2021) were obtained from Google Earth Pro 7.3.6 (https://www.google.com/earth/versions/#earth-pro). The map created in Google Earth Pro 7.3.6, Erdas Imagine 9.1(https://erdas-imagine.sofware.informer.com/9.1/) and Adobe Photoshop CS3 (https://adobe-photoshop-cs3-update.en.sofonic.com/).
Over the past two decades, the cost of solar energy has decreased dramatically, making it increasingly competitive with conventional energy sources. One of the most notable trends has been the substantial drop in solar module prices. Between 2006 and 2015, the average price per watt fell by approximately 82.5%, from $4 to $0.70. This sharp decline is widely attributed to continuous improvements in photovoltaic technology, increased manufacturing efficiency, and the realization of economies of scale in global production³¹. Solar trees will have significantly improved installation capacity compared to current levels in the not-too-distant future due to economies of scale if the demand for solar trees increases alongside technological advancements.
Google Earth imagery provides compelling visual evidence of extensive landscape transformation, with the once-green coastal forest largely replaced by artificial structures, resulting in a highly heterogeneous environment. As shown in Fig. 4; Table 3, approximately 98% of the forested area was converted into dark gray solar panel surfaces following the completion of the flat-panel solar project. This large-scale land conversion alters the coastal environment’s visual character and suggests significant ecological disruption, including potential loss of native vegetation, habitat fragmentation, and reduced biodiversity. In contrast, the 2012 satellite imagery, captured when solar trees were installed, demonstrates that solar infrastructure can be integrated into the landscape with minimal ecological disturbance. The preserved forest canopy visible in the earlier imagery highlights the potential for low-impact renewable energy development. These findings underscore the importance of selecting solar technologies and spatial arrangements that align with environmental conservation goals, particularly in ecologically sensitive areas such as coastal forests³².
The linear arrangement of solar power plants has a very important meaning from the perspective of long-term preservation of the natural beach environment. Since solar energy can be obtained without damaging the coastal forest cover, the benefits that green areas provide to humans, such as carbon absorption, can be enjoyed as it is. The green space where solar trees are linearly arranged will continue to contribute to preserving the coastal natural environment and its associated ecological benefits. The coastal forest landscape before the construction of the flat fixed panel plant provides visual evidence (Fig. 4a) that solar trees could offer nature-friendly psychological stability by providing a space where citizens can rest comfortably in their natural state. Citizens will be able to enjoy nature observation activities such as plant collection, insect observation, and bird watching in the solar tree forest. Further, local residents will be able to enjoy coastal forest recreation such as mountain climbing and hiking in the mountainous area where solar trees are installed.
South Korea ranks among the world’s most densely populated nations³³. Multiple studies have emphasized the ongoing increase in land prices across the country³⁴. In fact, research shows that South Korea has the third highest land prices globally³⁵. The cost of land acquisition in South Korea exceeds that of constructing a solar power plant. Given that solar trees require only a small installation area, they offer significant cost advantages over flat fixed panels in countries with high land prices such as South Korea. A previous study examined the relationship between electricity demand and national land area among forty-two major countries worldwide³⁶. South Korea ranked the lowest among these nations due to its combination of high electricity demand and limited land resources available for solar energy development. In the process of installing solar power plants in South Korea, landowners may be eligible for government subsidies and are also granted exemptions from certain land use regulations²¹. The recent surge in solar installations across the country reflects the expectation of profits driven more by increasing land values than by revenue from electricity generation³⁷. These conditions indicate that South Korea represents a favorable environment for solar tree investment.
Solar tree technology requires further development to reduce installation costs to match conventional fixed panel systems. Market introduction of solar panels specifically designed for solar trees by major manufacturers could accelerate their widespread adoption. However, it is difficult for individual companies to take the initiative in the solar tree business because it is less likely to take a risk burden on initial cost when the market outlook is uncertain. Therefore, in the initial stage of solar tree adoption, international organizations such as the Green Climate Fund (GCF) or the South Korean government must invest financial resources to develop solar tree technology. This study aims to inform discussions about specialized solar modules for solar trees compared to conventional fixed panels.
A key factor in evaluating the energy production capacity of solar trees compared to traditional flat panel systems is the selection of the solar panel type to be integrated into the tree structure. Equally important is determining the number of solar trees to be deployed within the designated study area, as outcomes can vary significantly depending on panel specifications and the extent of deployment. In designing comparative assessments between solar trees and conventional flat fixed PV systems, it is essential to account for the variability in panel size, orientation, and configuration associated with solar tree installations. Solar panels’ dimensions and power ratings can differ based on the intended evaluation period, the study area’s spatial constraints and environmental conditions. These contextual factors can substantially influence energy output and, if not properly considered, may lead to biased or unrepresentative results. To address this limitation, future studies should conduct comparative analyses using a range of commercially available solar panels that are technically compatible with solar tree designs. Incorporating such variability is essential for enhancing the objectivity, reproducibility, and generalizability of findings regarding the performance of solar trees relative to conventional flat fixed PV systems.
The geographical scope of this study was deliberately confined to a coastal mountainous region, which allowed for clearly defined research boundaries and facilitated data collection under relatively controlled conditions. While this localized focus allowed for a more in-depth and context-sensitive analysis, it also limited the generalizability of the findings to other geographic or environmental contexts. To address these limitations, future research should incorporate a broader range of case study areas to strengthen statistical validity and establish a more generalizable foundation for the claim that solar trees can generate more energy while occupying less space than conventional flat fixed solar panels. Furthermore, the findings are constrained by the absence of empirical validation regarding energy production performance per unit area in relation to key physical site characteristics—such as topography, drainage, soil composition, and vegetation. Addressing this limitation in future studies will be essential to enhancing the robustness and broader applicability of the results.
Solar trees, as simulated through Google Earth, provided both visual and quantitative evidence that linearly arranged solar trees are capable of achieving higher installed capacity than standard flat fixed panels, while occupying smaller land area, avoiding deforestation. This study holds significance in that it presents realistic evidence supporting the application of the installation capacity concept as a basis for conducting uniform comparisons of photovoltaic modules developed by different manufacturers. Therefore, the results of this study may serve as an objective reference for prioritizing the adoption of solar trees in solar power projects situated within mountainous landscapes. The New York Declaration on Forests, which was adopted at the United Nations Secretary-General’s Climate Summit held in New York in 2014, included a pledge to reduce the global rate of deforestation by half by the year 2020 and to restore hundreds of millions of acres of degraded land. However, including South Korea, the international community has failed to maintain this promise. The author hopes that the result of this study will encourage countries worldwide to take concrete action against deforestation rather than issuing declarations that reiterate past rhetoric. The findings of this paper offer realistic suggestions for the over 140 countries worldwide committed to working towards halting and reversing forest loss by 2030 in the Glasgow Leaders’ Declaration on Forests and Land Use to establish a policy to introduce solar trees in forestry landscapes specifically. Policies promoting the adoption of solar trees in forestry landscapes (e.g., by giving subsidies and incentives) can accelerate the adoption of this technology, thereby promoting renewable energy development. In the long run, increasing the national solar tree installation rate can help to reach carbon neutrality targets.
The datasets utilized during the current study are available in the data archive repository maintained by Google Earth Pro version 7.3.6 (https://www.google.com/earth/versions/#earth-pro).
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Korea Maritime Institute, 26, Haeyang-ro 301 beon-gil, Yeongdo-gu, Busan, Republic of Korea
Dan-Bi Um
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Um, DB. Superior energy output of solar trees compared to flat fixed panels in coastal forest installations. Sci Rep 15, 30287 (2025). https://doi.org/10.1038/s41598-025-12313-y
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Received: 07 April 2025
Accepted: 16 July 2025
Published: 19 August 2025
Version of record: 19 August 2025
DOI: https://doi.org/10.1038/s41598-025-12313-y
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