Mentor’s Comment: As the push for sustainable energy intensifies, concerns are rising over the efficiency limits of widely used silicon photovoltaics. With the growing need for green hydrogen and land constraints, experts are questioning whether next-gen solar technologies offer better solutions. India must invest in efficient, diverse, and scalable innovations to meet climate goals and ensure energy self-sufficiency.

Today’s editorial analyses the concerns that are rising over the efficiency limits of widely used silicon photovoltaics. This topic is important for GS Paper III (Environment) in the UPSC mains exam.

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Why in the News?

Recently, as the global need for clean energy has increased and countries aim to fulfill their climate promises, silicon solar panels have become the most popular choice, changing the look of places from city rooftops to large solar farms in villages.

What limits silicon photovoltaics in meeting India’s climate goals?

• Low Energy Efficiency: Silicon solar panels have an in-field efficiency of only 15–18%, meaning a significant portion of solar energy is not converted into electricity. Eg: In Rajasthan, more panels are required to meet energy demand, increasing cost and land use due to low conversion efficiency.
• High Land Requirement: Due to their low efficiency, silicon panels need a larger surface area to generate the same output compared to newer technologies. Eg: The Rewa Solar Park in Madhya Pradesh covers over 1,500 hectares, reducing land availability for agriculture and conservation.
• Slow Climate Impact: Despite growing solar capacity, CO₂ levels have risen from 350 ppm in 1990 to ~425 ppm in 2025, indicating renewables are not scaling fast enough. Eg: Even after installing 4.45 TWh of renewable energy by 2024, India remains behind on its climate targets.
• Environmental Footprint of Manufacturing: The production of silicon panels involves high energy use and toxic chemicals, partially offsetting their green benefits. Eg: Most panels are imported from China, where coal-powered factories dominate, adding to indirect emissions.
• Incompatibility with Advanced Applications: Silicon PVs are less suitable for high-efficiency applications like green hydrogen production, which needs more consistent, high-output energy. Eg: In pilot projects in Gujarat, using silicon panels reduces the overall efficiency of green hydrogen production due to energy losses.

Why rethink electrolysis-based green hydrogen?

• High Energy Consumption: Electrolysis requires more energy to produce green hydrogen than the energy hydrogen provides when used, making the process energy-inefficient. Eg: In India’s pilot projects in Ladakh, the high electricity input from solar panels results in low net energy gain, raising concerns about economic viability.
• Storage and Transportation Challenges: Hydrogen has very low density, making it difficult and expensive to store and transport, often requiring high-pressure tanks or cryogenic conditions. Eg: In hydrogen mobility projects, such as those in Delhi, leakage and compression issues have hampered safe and cost-effective deployment.
• Compounding Energy Losses in Conversion: Using green hydrogen to produce green ammonia or methanol, and then extracting hydrogen back, leads to multiple stages of energy loss. Eg: In proposed export hubs like Vizag, converting hydrogen to ammonia for shipping and then reconverting it abroad reduces overall energy efficiency.

How do land and efficiency issues impact India’s solar push?

• Low Efficiency Increases Land Requirement: Silicon solar panels with 15–18% efficiency require larger surface areas to generate the same energy as advanced solar technologies. Eg: In Rajasthan’s Bhadla Solar Park, vast desert land is used to compensate for low panel efficiency, which limits deployment in land-constrained states.
• Urbanisation Limits Land Availability: Rapid urban expansion and the need to conserve green zones reduce the availability of suitable land for large-scale solar projects. Eg: In Mumbai’s metropolitan region, limited open space has pushed the focus toward rooftop solar, which has its own technical and regulatory hurdles.
• Hinders Achievement of Renewable Energy Targets: The inefficient land-to-energy ratio slows down the pace of solar capacity expansion, affecting progress toward India’s net-zero commitments. Eg: In Tamil Nadu, where land is both fertile and scarce, competing demands between agriculture and solar installations have delayed key solar proposals.

What role can artificial photosynthesis play in renewable energy?

• Direct Conversion of Sunlight into Fuel: Artificial photosynthesis (APS) mimics natural photosynthesis to convert sunlight, water, and CO₂directly into fuels like green methanol or hydrogen, offering a clean, efficient alternative to traditional energy-intensive processes.
• Bypasses Inefficiencies in Current Technologies: APS has the potential to eliminate multiple energy-loss steps such as electrolysis, storage, and reconversion, thereby enhancing the overall energy efficiency of renewable fuel production systems.

Why invest in next-gen renewable tech like RFNBO? (Way forward)

• Enhances Energy Independence: Renewable Fuels of Non-Biological Origin (RFNBO) can reduce India’s heavy reliance on imported fossil fuels (currently ~85%), promoting energy self-sufficiency in a geopolitically volatile world.
• Supports Diverse and Efficient Decarbonisation: RFNBO technologies enable the production of cleaner fuels like green hydrogen, ammonia, and methanol using renewable electricity, offering higher efficiency and adaptability for industrial and transport sectors.
• Future-Proofing India’s Energy Strategy: Investing in RFNBO ensures India is aligned with global clean energy innovations, allowing it to meet net-zero targets and remain competitive in emerging green fuel markets.

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