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Scientific Reports volume 15, Article number: 44687 (2025) Cite this article
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Iran’s arid and semi-arid climate necessitates innovative strategies to address interlinked water and energy challenges. Floating solar photovoltaic (FSPV) systems offer a dual advantage by simultaneously generating clean electricity and reducing reservoir evaporation. This study assesses the technical, environmental, and economic feasibility of FSPV deployment across 117 major reservoirs in Iran using ArcGIS-based spatial analysis, high-resolution Solargis solar data, and evaporation modeling. Results show that covering just 0.5% of reservoir surfaces could generate approximately 36,000 MW annually—equivalent to 40% of Iran’s current power capacity—while preventing 4.2 million cubic meters of water loss each year. Economic analysis estimates an average CAPEX of USD 700,000 per MW and a competitive levelized cost of electricity (USD 0.048–0.065 per kWh). Moreover, FSPV implementation could offset up to 6,725 tons of CO₂, 14 tons of SO₂, and 25 tons of NOₓ per megawatt compared with fossil-fuel generation. These findings highlight FSPV as a strategic solution to strengthen Iran’s water–energy nexus and guide sustainable policy and investment decisions.
Although water covers over 70% of the Earth’s surface, only around 3% is fresh water, and less than one-third of the global average annual precipitation occurs in Iran¹;². The country’s geographic position within the global arid and semi-arid belt³, coupled with its uneven population distribution, has created pronounced spatial mismatches between water availability and demand. The population is concentrated in regions with limited hydrological capacity, leading to heavy reliance on inter-basin water transfers, intensive groundwater extraction, and the construction of large reservoirs to stabilize supply⁴.
Over the past decades, Iran has experienced multiple episodes of severe drought, intensifying pressure on water resources⁵;⁶. These challenges are compounded by increasing temperatures due to climate change, which accelerate evapotranspiration rates and reduce snowpack in upstream catchments, thereby diminishing inflows to reservoirs. Population growth and urbanization further exacerbate demand, while agricultural water use—accounting for over 90% of withdrawals—remains largely inefficient due to outdated irrigation practices⁷;⁸;⁹.
The expansion of surface water storage infrastructure has been a key element of national water policy. The number of large dams increased from 78 in the late 1980s to 354 by 2015¹⁰, significantly increasing the total volume of regulated surface water. While dams have improved flood control and enabled seasonal water regulation¹¹, they also create large exposed surfaces subject to high evaporation losses. Annual open-water evaporation from reservoirs is estimated at around 12 billion m³¹⁰, representing a significant proportion of the nation’s renewable freshwater resources. This loss is particularly severe in central and southern provinces where average annual evaporation rates exceed 2,000 mm¹².
Parallel to these hydrological challenges, Iran’s energy system faces mounting pressures. Electricity demand exhibits strong seasonality, with peak loads during the hot summer months coinciding with reduced hydropower output due to diminished inflows. The electricity generation mix is dominated by fossil fuel-based thermal power plants, which not only emit greenhouse gases and air pollutants but also consume considerable amounts of water for cooling. In 2019, the major power plants consumed approximately 12 million m³ of water for electricity production, further entrenching the interdependence between water scarcity and energy security¹³. Given these dynamics, the search for integrated, multi-benefit solutions that can simultaneously conserve water and generate renewable energy is both urgent and essential.
Floating solar photovoltaic (FSPV) systems have emerged over the last two decades as an innovative approach to mitigating both land-use conflicts and evaporation losses while expanding renewable electricity generation. The first commercial-scale FSPV installation was commissioned in 2008 at the Far Niente Winery in California, USA, following a smaller pilot system in Aichi, Japan, in 2007¹⁴. Countries such as Japan, China, South Korea, India, Indonesia, Thailand, the Netherlands, Singapore, and Brazil have integrated FSPV into their renewable energy strategies, leveraging synergies between existing water bodies and solar energy potential¹⁵.
The global installed capacity of FSPV systems expanded from 70 MW in 2015 to over 1.3 GW by 2019, corresponding to an approximate compound annual growth rate (CAGR) of 107%, reflecting the technology’s rapid commercialization (Acharya & Devraj, 2019;¹⁴.
Japan, for example, operates several of the largest FSPV systems worldwide, many exceeding 10 MW in capacity, often deployed on irrigation ponds and hydropower reservoirs¹⁶. China has invested heavily in FSPV for both inland water bodies and former mining pits, linking projects to rural electrification and industrial redevelopment¹⁴. South Korea’s Hapcheon Dam project, a benchmark for integrating FSPV with hydropower infrastructure, demonstrates a 40% reduction in reservoir evaporation alongside improved PV efficiency by approximately 15% due to water-based cooling¹⁷.
Key benefits driving this rapid adoption include:
Optimal land use efficiency: By deploying PV on reservoir surfaces, FSPV systems avoid competition with agricultural lands, urban areas, and ecologically sensitive habitats.
Enhanced electrical performance: The cooling effect of water surfaces can improve PV efficiency by 5–15% relative to ground-mounted installations, depending on climatic conditions¹⁸.
Evaporation mitigation: Shading of reservoir surfaces can reduce evaporation losses by up to 40%, conserving millions of cubic meters of water annually¹⁹.
Water quality improvement: Reduced sunlight penetration can suppress excessive algal growth, thereby improving water quality and lowering treatment costs.
While these benefits are site-specific, the underlying principles are applicable to a broad range of geographies. In arid and semi-arid regions—such as Australia, Jordan, Saudi Arabia, and Pakistan—FSPV has been identified as a strategic tool for enhancing water–energy resilience²⁰;²¹;²²;²³. These countries face challenges similar to Iran: high solar irradiance, elevated evaporation rates, and land-use constraints that limit expansion of conventional PV. By integrating FSPV into existing water infrastructure, they have achieved measurable gains in both renewable energy generation and water conservation.
Recent reports from international organizations highlight the accelerating global adoption of floating solar technologies. The World Bank (2023) and IRENA (2022) indicate that global installed FSPV capacity surpassed 3 GW by 2022, with over 400 projects either operational or under construction across 45 countries. These trends confirm FSPV as a rapidly maturing technology, particularly suited to arid and semi-arid regions facing water scarcity. However, the application of FSPV in Middle Eastern contexts remains underrepresented in the scientific literature, underscoring the need for region-specific assessments such as the present study.
Despite Iran’s extensive reservoir network and favorable solar potential, the deployment of FSPV remains limited. The Mahabad pilot plant, generating approximately 200 kWh/day, represents one of the few operational examples in the country²⁴. Current research on FSPV in Iran is largely fragmented, focusing on individual case studies, preliminary technical assessments, or comparative analyses between floating and ground-mounted PV systems²⁵;²⁶;²⁷. There has been no systematic, nationwide evaluation that combines technical, environmental, and spatial analyses to guide large-scale deployment.
Internationally, comprehensive assessments have proven invaluable in informing policy and investment decisions²⁸. developed a multi-criteria site selection framework for FSPV in Thailand’s hydropower reservoirs, incorporating technical, economic, and environmental factors²⁹. applied a similar methodology in South Korea, prioritizing sites based on water depth, solar radiation distribution, and carbon emissions reduction potential. These approaches not only identify optimal sites but also provide quantitative metrics for potential energy generation, water savings, and environmental benefits.
The present study addresses the knowledge gap in Iran by conducting a national-scale assessment of FSPV potential across 117 major reservoirs. Using ArcGIS-based spatial analysis, high-resolution solar irradiation data from Solargis, and evaporation modeling based on synoptic station observations, the study evaluates multiple deployment scenarios: covering 0.5% and 0.1% of unshaded reservoir areas and installing fixed 1,000 m² arrays per dam. The analysis estimates corresponding electricity generation, water savings, and pollutant emissions reductions, offering a detailed perspective on both technical feasibility and environmental impact.
By aligning with global best practices and adapting them to Iran’s specific climatic, hydrological, and infrastructural context, this research not only provides actionable recommendations for domestic policymakers but also presents a replicable methodological framework for other arid and semi-arid countries facing similar water–energy nexus challenges.
This study is the first to conduct a nationwide, data-driven assessment of FSPV potential in Iran, integrating hydrological, solar, and spatial parameters within a unified analytical framework. By combining evaporation modeling, geospatial mapping, and techno-economic analysis, it introduces a comprehensive methodological approach that can inform national policy and serve as a reference for other water-stressed countries pursuing integrated water–energy strategies.
This research investigates the potential of Iran’s main dams, obtaining information from governmental water resources management company, including their location and reservoir volume. Satellite images were used to check the maximum lake levels of Iran’s dams, with the highest level occurring in April 2019 due to floods. To improve accuracy and correct borders, raster maps were created using the OpenStreetMap site. Figure 1.a displays the location of the country’s main dams and their lakes. Furthermore, the study utilized observational evaporation data from 339 synoptic weather stations in the country (Fig. 1.b) to analyze the country’s weather patterns.
(a) Spatial distribution of major dams and their reservoirs in Iran. (b) Geographical locations of the 339 synoptic weather stations used in the study.
The Meteorological Organization’s daily synoptic data obtained from³⁰ was utilized to accurately determine evaporation amounts and related parameters, gathered from all stations, and prepared as the annual evaporation amount for 2019 using daily data. Furthermore, the evaporation map was created using station observation data and the ArcGIS software interpolation method. Besides, the lake evaporation map of dam reservoirs was produced, and the evaporation amount of each dam was calculated separately, resulting in the calculation of annual evaporation amounts of each reservoir.
The energy produced by solar panels is influenced by the surface of the panels and the average radiation irradiated. The efficiency of solar panels in converting solar radiation into electricity can be diminished by factors like electrical equipment, temperature, and environmental effects like dust. The calculated solar energy is based on Eq. 1.
Where E is the production energy in kilowatt hours, A is the total cross-sectional area of ​​the solar panels in square meters, r is Solar panel efficiency in percentage, H is the average annual amount of radiation on the surface of solar panels in kilowatt hours per square meter for each year and PR is the performance ratio in which reducing coefficients are used. These coefficients include reduction due to converter, temperature, cable, DC cable, AC shadow, weak radiation, dust, and other reducing factors.
The rate of reduction of evaporation caused by floating solar panels on dam reservoir water levels is calculated by multiplying the occupied surface, the rate of evaporation, and the reducing factor. The reducing factor is determined according to the type and reflective performance of the panel, the coverage percentage and its performance, and indicates the rate of evaporation among the panels.
The amount of energy produced from floating solar panels in the dam reservoirs of Iran, was calculated according to Eq. 1, using constant coefficients and related parameters. The Meteorological Organization’s data on the radiation parameter, which are crucial for calculating solar energy production, was significantly missing. Therefore, the use of data from the global reference site solargis.com was used. The site provided a solar radiation map, and the average amount of radiation was calculated for each dam reservoir.
The 2019 water zone area was used to calculate the occupied area of dam reservoirs for solar energy production, with the largest reservoir recorded due to a flood. The dam lake’s shading was isolated using the Hilshade operation in ArcGIS software due to the unique topography of each region and the surrounding mountains, resulting in a more accurate representation of the lake. As a result, the calculation of solar energy production was conducted on an area of the dam lake without shadow. The selection of 0.5% and 0.1% reservoir surface coverage follows benchmarks used in previous large-scale FSPV feasibility studies in Asia and Europe, which balance technical feasibility, cost efficiency, and minimal ecological disturbance³¹;²⁸. The Hillshade shadow-masking process in ArcGIS was validated by cross-checking shaded areas against high-resolution Google Earth imagery from selected reservoirs. The Solargis radiation data was selected due to its consistent national coverage and high spatial resolution (≈ 250 m), which overcomes the sparse distribution and missing data issues of Iran’s synoptic station network. The performance ratio (PR) of 0.70 reflects standard values for utility-scale PV installations in similar climates and incorporates derating factors for temperature, dust, and electrical losses.
The technical assumptions used in this study are based on commercially available systems. The FSPV arrays consist of monocrystalline silicon PV modules with 20% efficiency and a degradation rate of 0.5% per year³². The floating structure is composed of high-density polyethylene pontoons with 25-year durability and UV resistance³³. Arrays are anchored using cable-and-anchor systems adapted to reservoir bathymetry, ensuring stability under fluctuating water levels. Power conversion employs central inverters with 98% efficiency and grid interconnection capability at 20–30 kV. Regular cleaning is performed with automated water-spray systems to minimize dust accumulation, reducing manual labor requirements. Table 1 demonstrate assumptions summary.
The amount of produced energy is calculated by considering different areas and is displayed in Table 2. The results were calculated for 0.5% and 0.1% of the unshaded area of dam reservoirs, considering a fixed 1000 square meters for each dam. The volume of evaporation based on the occupied area and the evaporation rate of each dam tank was calculated and aggregated. Also, according to the per capita consumption of drinking water in Iran, 100 cubic meters per year, and equivalent to approximately 275 L per day have been considered. Figure 2 presents a comprehensive map comparing the solar energy production potential of major dam reservoirs across Iran. The map reveals significant regional variations, with southern and central regions exhibiting the highest potential due to greater solar irradiation and larger reservoir areas. Notable examples include the Karun, Karkheh, and Dez dams, which collectively offer substantial energy production opportunities. Conversely, reservoirs in northern and northwestern regions show lower energy potential due to smaller reservoir sizes and reduced solar radiation levels. This analysis underscores the importance of regional prioritization in the deployment of FSPV systems to maximize environmental and economic returns.
Spatial distribution of the estimated floating solar photovoltaic (FSPV) energy production potential across major dam reservoirs in Iran.
Figure 2 illustrates the solar energy production potential across Iran’s primary dam reservoirs based on regional characteristics such as solar irradiation levels and reservoir surface areas.
The analysis highlights considerable regional variability:
Southern and Central Regions: These areas exhibit the highest energy production potential. Dams such as Karun, Karkheh, and Dez stand out due to their large reservoir surfaces and high solar radiation levels. These factors make them prime candidates for large-scale FSPV implementation.
Northern and Northwestern Regions: In contrast, dams in these regions display lower energy potential, primarily due to smaller reservoir sizes and lower solar irradiance caused by geographic and climatic constraints.
This disparity underscores the importance of adopting a regional prioritization strategy when planning FSPV system deployment. Policymakers and investors should focus initial investments on high-potential reservoirs to maximize energy output and ensure cost-effectiveness.
The Table 2 results highlight the transformative potential of FSPV systems for Iran’s energy and water sectors. The values in Table 2 were calculated using Eq. (1), which relates energy output (E) to panel area (A), average annual solar radiation (H), module efficiency (η), and performance ratio (PR). Reservoir-specific evaporation data were derived from interpolated 2019 synoptic station records, and reduction factors were applied based on 0.5% and 0.1% surface coverage scenarios. The volume of water saved (Million Cubic Meter (MCM)) corresponds to the product of evaporative rate (mm/year) and shaded reservoir area, adjusted for local climatic coefficients. All radiation data were obtained from Solargis, ensuring consistency across spatial analyses.
By utilizing just 0.5% of the unshaded surface area of dam reservoirs, approximately 36,000 MW of electricity could be produced annually. This figure represents a significant contribution, equivalent to nearly 40% of Iran’s current power plant capacity. Additionally, the prevention of 4.2 million cubic meters of water evaporation could meet the annual drinking water needs of over 42,000 individuals, mitigating the water stress exacerbated by climate change. The results align with studies from Thailand, South Korea, and Brazil, where FSPV systems have successfully reduced evaporation while achieving significant energy outputs. For instance, South Korean reservoirs demonstrated a 40% reduction in evaporation and improved solar energy efficiency by 20% due to water-based cooling. Such findings validate the potential benefits highlighted in this study for Iran.
The main cost and challenge of building a solar power plant is acquiring land and its price, after securing an investor. With sufficient investment, using solar panels can add over a third of the current power plant capacity to the existing situation. Furthermore, the secondary wastes, including water resource consumption and fuel supply, and the resulting pollutant emissions, will not be produced. Besides, the project will not only prevent water consumption but also provide drinking water to nearly 42 thousand people by preventing the evaporation of water to a volume of 4.2 million cubic meters. Also, according to Table 1, by examining the area of the country’s dam reservoirs, or 1000 square meters from each dam, a significant electricity production of 7245 and 3512 megawatts can be achieved. In this scenario, the stored water can be utilized to supply drinking water to nearby villages with a total population of 5,200 and 2,200 people.
The technical sector faces the challenge of providing land for solar panel maintenance and care and maintenance of them, particularly in dam reservoirs. This problem is resolved by the Ministry of Energy, as the land is free and available for natural maintenance, leading the problem to be resolved independently. Besides, the issue of heating solar panels and reducing their performance has been effectively resolved by incorporating water into the panels’ design. Integration of FSPV with thermoelectric generators (TEGs) offers a novel pathway to enhance energy yield and enable partial night-time power generation. In addition to the cooling benefits that floating arrays provide to PV modules, reservoir thermal stratification creates exploitable water–air temperature differentials which can be harvested by thermoelectric modules to produce electricity during low-irradiance and nocturnal periods. Recent materials advances show that high-performance thermoelectric compounds are now reaching conversion efficiencies and temperature ranges relevant to reservoir-based TEGs: Bi₆Cu₂Se₄O₆ superlattices exhibit a lattice-vibrational hierarchy and mean-free-path filtering that support stable n-type transport with ZT peaks in distinct temperature windows³⁴; SnSe-based crystals—when engineered via multiband activation and defect chemistry—achieve very high average ZT across broad temperature ranges³⁵; SrSnSe₂ shows anisotropic Rashba band features and strong multi-phonon scattering conducive to high ZT at elevated temperatures³⁶; and Zintl-phase BaCaSn displays lone-pair–driven rattling dissipation and very low lattice thermal conductivity³⁷. Complementary mechanistic strategies (symmetry-breaking to amplify lone-pair expression, cation-driven vibrational hierarchy, and phonon diffusion engineering) provide materials design routes that can shift peak TE performance into temperature windows accessible in stratified reservoirs³⁶;³⁸;³⁹. Finally, resonant-level engineering in SnSe⁴⁰ demonstrates practical band-engineering approaches to improve Seebeck matching and device-level output. Taken together, these advances indicate that embedding compact TEG modules into FSPV platforms (for example on moored pontoons with thermal exchangers to deeper layers) can create a day–night complementary supply that enhances round-the-clock utilization of the same reservoir footprint.
Using the closest place of the dam lake to the dam itself for better control and maintenance is also a good solution for proper operation. Therefore, a suitable investor in this sector can meet a significant portion of the country’s electricity consumption needs, particularly during the hot seasons when power plants peak production. The study evaluates environmental potential in two parts: through clean energy use and pollution-free fuel consumption, as well as water consumption prevention and storage.
While standalone FSPV systems offer substantial environmental and operational benefits, integrating them into hybrid renewable energy configurations can significantly enhance system reliability and utilization efficiency. Recent advances in thermoelectric (TE) materials—such as Bi₆Cu₂Se₄O₆ superlattices with lattice vibrational hierarchy and mean-free-path filtering³⁴, high-performance SnSe crystals optimized through multiband activation and defect engineering³⁵, SrSnSe₂ compounds exhibiting anisotropic Rashba spin–orbital splitting and strong four-phonon scattering⁴¹, and Zintl-phase BaCaSn with lone-pair-induced rattling dissipation³⁷—open new possibilities for coupling FSPV with thermoelectric generators, wind turbines, small hydropower, or concentrated solar power. Such hybrid configurations can leverage complementary generation profiles, mitigate intermittency while maximizing the spatial and thermal resources available at reservoir sites. Moreover, integrating TE devices with FSPV could enable simultaneous harvesting of solar and thermal energy, thereby increase overall plant capacity factors and support grid stability.
Despite the promising benefits of FSPV, several technical challenges must be addressed to ensure large-scale viability. Anchoring systems must be adaptable to fluctuating water levels and varying reservoir bathymetry. Biofouling on module surfaces can reduce efficiency over time, requiring periodic cleaning and anti-fouling materials. Grid integration may also pose challenges due to the intermittent nature of solar power, necessitating advanced inverters and flexible grid management. Addressing these issues through targeted pilot projects and localized engineering solutions will be critical for scaling up FSPV deployment in Iran.
The produced electricity in Iran’s power plants in 2019, the type and amount of fuel consumption, and the conversion coefficients of each fuel type into pollutants, are presented in Table 3. From an environmental perspective, the adoption of FSPV systems would eliminate the need for fossil fuel-based electricity generation, preventing the release of 6,725 tons of CO₂, 14 tons of SO₂, and 25 tons of NO_x per megawatt. Moreover, the zero water consumption of FSPV systems offers critical advantages in a country where traditional power plants consumed 12 million cubic meters of water in 2019 alone.
These findings position FSPV systems as a cornerstone of Iran’s transition towards a sustainable energy future, with the added benefit of preserving critical water resources. Strategic prioritization of reservoirs with high solar irradiation and large surface areas will be key to maximizing these benefits. The production of these pollutants has a secondary impact on both the environment and human health⁴². In 2016, the World Health Organization reported that over 4 million people worldwide died due to air pollution⁴³, highlighting the importance of reducing fuel consumption to prevent secondary effects and consequences. Floating photovoltaic (FPV) systems offer significant water savings (4.2 million m³ annually) that can be strategically allocated for agricultural irrigation or drinking water supply⁴⁴. While moderate FPV coverage (40–60%) effectively controls algal blooms through light limitation⁴⁴, excessive coverage may disrupt aquatic ecosystems. The systems provide ecological advantages over ground-mounted PV by avoiding land-use change⁴⁵, though mooring installations may temporarily affect benthic habitats. Optimal deployment requires site-specific assessments to balance energy production with water conservation and ecosystem protection⁴⁴.
While the environmental and technical benefits of FSPV systems are compelling, their long-term operational performance is influenced by several complex factors. These include extreme weather events (e.g., storms, heatwaves), sediment deposition altering reservoir bathymetry, biofouling on module surfaces, and gradual performance degradation due to ultraviolet exposure and material fatigue⁴⁶. Incorporating design measures such as UV-resistant coatings, anti-fouling materials, and adaptive anchoring systems can mitigate these risks and enhance system resilience. Detailed environmental impact assessments should be conducted prior to large-scale deployments to ensure ecological compatibility.
The per capita water consumption for per megawatt of electricity production for all types of power plants in Iran was calculated based on the amount of electricity produced and water consumed in 2019 by the power plants (Table 4).
According to Table 4, Iran’s main power plants consume 12 million cubic meters of water for 32,130 megawatts of electricity. Using floating solar panels, no water is consumed, saving 4 million cubic meters, or 16 million cubic meters, and producing the same amount of electricity.
Beyond water savings and emission reduction, potential ecological risks of FSPV deployment were examined. Shading can alter reservoir thermal stratification and impact dissolved oxygen, phytoplankton, and fish populations⁴⁶;⁴⁷. Bird collisions with PV modules and floating structures are also possible, especially in migratory corridors. To mitigate these risks, environmentally compatible cleaning agents, adequate spacing between arrays, and bird deterrent measures are recommended. Sediment transport and flow regime changes should be further studied using hydrodynamic models.
A preliminary life cycle assessment (LCA) suggests that FSPV produces ~ 40 gCO₂-eq/kWh, significantly lower than coal (> 900 gCO₂-eq/kWh) and natural gas (> 450 gCO₂-eq/kWh). These results reinforce the environmental superiority of FSPV over fossil-based electricity generation⁴⁸.
Economic Feasibility.
The economic viability of large-scale FSPV deployment in Iran was assessed by estimating capital expenditure (CAPEX), operational expenditure (OPEX), and the levelized cost of electricity (LCOE). Based on international benchmarks, the CAPEX of FSPV projects is estimated at USD 650,000–750,000 per MW, depending on reservoir location and floating infrastructure requirements⁴⁹;⁵⁰. For this study, an average of USD 700,000/MW was assumed, consistent with previous feasibility studies in Asia³¹;⁵¹. OPEX, including periodic cleaning, insurance, labor, and maintenance, typically represents 1.5–2% of CAPEX annually³³.
Electricity revenues were modeled using current average Iranian wholesale tariffs of USD 0.035–0.045/kWh⁵², though the value could increase under renewable energy incentive schemes. A discount rate of 10% was applied, reflecting infrastructure project risks in Iran. Sensitivity analysis revealed that LCOE is most sensitive to variations in CAPEX and electricity pricing. The calculated LCOE of FSPV ranged between USD 0.048–0.065/kWh, competitive with natural gas combined cycle power plants in Iran (USD 0.045–0.060/kWh, including externalities)⁵².
These findings highlight that FSPV can achieve cost parity with fossil fuel generation, while delivering additional water conservation and emission reduction benefits not captured in LCOE metrics.
Climate change leads to a relative increase in temperature and a decrease in water resources. With the increase in the country’s population, the consumption of electricity is increasing as well as its per capita consumption. Therefore, the Ministry of Energy is implementing a policy to increase electricity production, making investment in this crucial area. In the meantime, due to the reduction of Iran’s water resources due to various factors^6,53,54, , better control over the existing source to address the main issue is mandatory. Iran’s hot and dry climate results in 70% of rainfall evaporation, affecting water storage behind dams. Changing the electricity production policy from fossil fuel power plants to clean energy is one of the main plans of the Ministry of Energy. Advanced countries have proposed the use of floating solar panels in dam reservoirs through similar studies and innovative method³¹.
The use of floating solar panels in dam reservoirs provides several main goals. By using the FSPV system, the Ministry of Energy is provided with free land for the purchase and provision of land, resolving a major challenge in the construction of a solar farm. Besides, water plays a crucial role in controlling heat and preventing the reduction in performance of solar panels due to temperature rise. On the other hand, solar panels prevent the evaporation of water from the reservoirs of Iran’s dams. In consequence, this research aims to explore the technical and environmental potential as a crucial initial step towards this direction.
This study confirms that floating solar PV can play a pivotal role in ensuring Iran’s energy and water security. Beyond its immediate quantitative benefits, FSPV represents a pathway toward integrated resource management in arid regions. Future research should focus on pilot-scale validation of technical and environmental performance, optimization of reservoir coverage ratios, and integration of hybrid FSPV–hydropower systems. These steps will enable policymakers and engineers to refine design standards, minimize ecological risks, and accelerate the transition toward sustainable energy–water systems.
Economic analysis indicates that FSPV requires an average CAPEX of $700,000 per MW, zero fuel costs, and a competitive LCOE compared to fossil-fuel alternatives, while OPEX is minimal, mainly for maintenance and cleaning. Sensitivity analyses confirm resilience to variations in electricity pricing, panel efficiency, and discount rates. Environmental evaluation emphasizes the need for careful site selection to minimize ecological impacts on aquatic ecosystems, sediment transport, and avian populations, while maximizing water conservation and energy production.
To promote FSPV deployment, Iran should adopt a multi-level policy framework integrating renewable energy and water management strategies. Specific actions include:
Introducing feed-in tariffs or premium tariffs tailored for FSPV projects to ensure financial viability.
Providing tax incentives and low-interest green loans for domestic investors and manufacturers of floating structures.
Including FSPV systems in national water management and energy transition plans to align with Iran’s long-term sustainability goals.
Facilitating international cooperation with leading countries such as Japan, Singapore, and the Netherlands to accelerate technology transfer and capacity building.
Establishing pilot projects on major reservoirs (e.g., Karun, Karkheh, Dez) to test technical performance and environmental impact under local condition.
The data that support the findings of this study are available from the corresponding author, Behzad Ghiasi, upon reasonable request. Inquiries regarding the data should be directed to: Behzad.ghiasi@ut.ac.ir.
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This work is based upon research funded by Iran National Science Foundation (INSF) under project No. 4000057.
Faculty of Environment, University of Tehran, Tehran, Iran
Behzad Ghiasi
Faculty of Agricultural and Natural Resources, Imam Khomeini International University, Qazvin, Iran
Hadi Ramezani Etedali
University of Tehran, Tehran, Iran
Hamzeh Tahsinpour
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B.G, H.R.E and H.T wrote the main manuscript text.B.G prepared all figures and tables.B.G and H.R.E reviewed the manuscript.
Correspondence to Behzad Ghiasi.
The authors declare no competing interests.
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Ghiasi, B., Etedali, H.R. & Tahsinpour, H. A strategic approach to water and energy sustainability: floating solar photovoltaics in Iran’s dam reservoirs. Sci Rep 15, 44687 (2025). https://doi.org/10.1038/s41598-025-28749-1
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Received: 14 July 2025
Accepted: 12 November 2025
Published: 29 December 2025
Version of record: 29 December 2025
DOI: https://doi.org/10.1038/s41598-025-28749-1
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