Why the world needs better green technologies, Pg 12.

Key Highlights:

• Silicon photovoltaics dominate solar power but have low efficiency (15–18%), requiring large land areas.
• New technologies like gallium arsenide thin films have achieved up to 47% efficiency in labs.
• India produces 6 GW of silicon cells, but efficiency gaps limit progress toward decarbonisation.
• Green hydrogen’s viability depends heavily on the efficiency of solar input, which silicon limits.
• Artificial photosynthesis (APS) and Renewable Fuels of Non-Biological Origin (RFNBOs) offer promising alternatives.
• Current hydrogen storage and transport technologies are costly and inefficient.
• India imports ~85% of its energy, highlighting the need for domestic R&D in futuristic renewables.

Detailed Insights:

• Limitations of Silicon Photovoltaics:
  • Require larger land area due to lower energy conversion, making them unsuitable for land-constrained or urbanising regions.
  • Slower scalability compared to the rapidly increasing global energy demand and CO₂ levels (now ~425 ppm).
• Green Hydrogen Production Challenges:
  • Electrolysis powered by silicon-based solar is energy-intensive, reducing net energy yield.
  • Storage and transport of hydrogen are technologically demanding due to its low density.
  • Converting hydrogen into green ammonia or methanol incurs additional energy losses, reducing overall efficiency.
• Need for Innovation:
  • Artificial photosynthesis (APS) mimics natural photosynthesis to directly convert CO₂ and water into fuels using sunlight.
  • RFNBOs aim to produce fuels without biomass, offering a more sustainable route.
  • A diversified portfolio of energy technologies is crucial for meeting net-zero targets and ensuring energy sovereignty.
• India’s Strategic Imperative:
  • To reduce import dependency and insulate itself from global shocks, India must increase investment in R&D, private sector partnerships, and next-gen energy innovation.
  • Emphasis on prevention over mitigation can reduce long-term environmental and economic costs.

Concepts Involved:

• Silicon Photovoltaics (PV): Solar cells using silicon semiconductors with average efficiency of 15–18%.
• Green Hydrogen: Hydrogen produced using renewable electricity through electrolysis; environmentally friendly but energy-intensive.
• Artificial Photosynthesis (APS): Technology that mimics plant photosynthesis to convert sunlight, CO₂, and water into fuels.
• Renewable Fuels of Non-Biological Origin (RFNBO): Synthetic fuels produced using renewable energy without biomass.