Highlighting the solar-agriculture-water nexus

The rapid expansion of solar energy in India presents challenges related to cropland encroachment and water-resource scarcity. To address these issues, a recent study ‘Assessment of the solar energy–agriculture–water nexus in the expanding solar energy industry of India: An initiative for sustainable resource management’ utilised open-access satellite observations and geographic information systems (GIS) technologies on the Earth Engine platform to create the Solar Panel Index (SPI) for efficient detection of solar farms, achieving a land use/land cover classification accuracy of 89%.

The study incorporated cropland, water availability, power grid, and land surface temperature datasets to generate a land suitability map. Sentinel-2 datasets, combined with Solar Panel Index, were used to identify solar farm locations and estimate their installed capacity within the study area.

The conversion of agricultural land into solar power plants has been a notable trend. Analysis of Land Use Land Cover (LULC) maps has shown a shift from agricultural use to solar installations across various states in India. This conversion raises concerns about potential impacts on soil quality and agricultural practices. Programs like the 'Kisan Urja Suraksha Evam Utthan Mahabhiyan (KUSUM) Yojana' and 'Saur Krushi Vahini Yojana (SKVY)' offer financial incentives to landowners for leasing their land for solar projects, but long-term installation of solar panels on agricultural land may affect land fertility and suitability for farming.

Impact on water resources

Water resource availability is crucial for solar power plants, with most relying on groundwater and surface water sources. The demand for water, both in quantity and quality, presents challenges, especially in water-stressed regions like Rajasthan, Madhya Pradesh, and Andhra Pradesh. Large solar power plants impact water management conditions, further straining water resources in certain areas.

A Land Suitability Map (LSM) has been developed to assess the viability of land for solar power generation, with Rajasthan identified as having the highest potential. However, concerns over the impact of solar projects on local water scarcity and soil quality emphasise the need for sustainable planning. Initiatives like the Pavagadh Solar Park in Karnataka have highlighted the importance of balancing solar energy expansion with environmental considerations to ensure long-term sustainability and minimal impact on local ecosystems.

The solar-agriculture-water nexus analysis at the Pavagadh solar park revealed strong correlations between solar power, agriculture, and water resources. This relationship highlights the interdependencies between solar energy production, agricultural activities, and water availability, emphasising the need for integrated land use planning and sustainable resource management in the context of solar power development in India.

Discussion

The study revealed that over 40% of all solar farms in the country are located on agricultural land, with the highest percentages in Karnataka (73.55%) and Tamil Nadu (68.81%). Additionally, areas with high installed capacity often coincide with low groundwater levels, worsening local water scarcity. Madhya Pradesh was found to have almost no power plants within 5 km of surface water bodies.

The rapid increase in solar plant projects has brought about significant changes in the environment, emphasising the importance of sound land resource management. The Solar Panel Index offers an efficient method for mapping solar farms using optical satellite data, holding promise for continuous monitoring and expansion of solar power. The Solar Panel Index algorithm, relying on widely available Landsat and Sentinel-2 images, enables the easy detection of solar farms through open-source data, aiding in the creation of datasets for solar farm locations and capacity estimation across India.

While solar power plant development can benefit specific regions, understanding the solar-agriculture-water nexus is crucial for sustainable growth. The encroachment of agricultural land for solar projects raises concerns about long-term impacts on food production. Field studies examining soil microbial communities beneath solar panels have revealed differences, indicating potential effects on soil health and nutrient cycles.

Balancing the trade-offs among food, energy, and water sectors necessitates comprehensive guidelines for sustainable land use planning. The integration of high-resolution Land Suitability Maps considering multiple sustainability factors ensures holistic decision-making, aligned with Sustainable Development Goals (#2, #6, #7).

The study provides insights for optimising resource use and aligning with sustainable development and energy security policies. Effective policies promoting sustainable resource management are vital, necessitating a holistic approach to address intersectoral interactions and enhance resilience to promote a sustainable future.

The following policies are recommended to promote sustainable resource management.

• Encouraging integrated planning approaches that take into account the interdependencies between water, energy, and food systems, and promote collaboration among stakeholders.
• Promoting education and awareness among stakeholders, such as farmers, policymakers, and the general public, about the benefits of sustainable resource management in the solar, agriculture, and water nexus.
• Developing regulatory frameworks that promote sustainable resource management practices, such as water-use permits or energy efficiency standards for buildings.
• Establishing land leasing agreements with solar developers that prioritise non-agricultural land, such as barren land or degraded forests, for solar development to reduce pressure on agricultural land.
• Implementing water pricing policies that reflect the true cost of water use, including the cost of treatment, distribution, and environmental impacts. This can encourage solar developers to use water more efficiently and promote sustainable water management practices.
• Promoting and incentivising the use of robotic cleaning systems for solar panels that can replace water usage and cut-short labour cost.

A holistic approach to resource management in the solar industry can drive economic growth and social development. Rigorous policies can prevent land encroachment globally. Effective water management policies and incentives for cleaning robots can alleviate water stress. These strategies promote sustainable natural resource use, aligning with economic and social development objectives. Policy guidelines from this research can facilitate balanced resource management in the solar sector, nurturing sustainable growth.

The full paper can be accessed here