Capturing sunlight in a bottle and using it when needed, Pg10

Key Highlights:

• India's rooftop solar capacity has reached 23 gigawatts (GW), with land-based solar panels generating approximately 150 GW of power.
• The Pradhan Mantri Surya Ghar Muft Bijli Yojana offers subsidies for home solar panel installations, costing about ₹30,000 per kW after subsidies.
• Researchers at the University of California have developed Molecular Solar Thermal (MOST) systems using molecular photo-switches to store solar energy.
• MOST technology utilizes molecules like 2-pyrimidone that convert into an isomer, Dewar pyrimidone, upon absorbing sunlight, storing thermal energy for later release.

Detailed Insights:

• Global adoption of 'green' solutions, including solar panels, is significantly influenced by initiatives from UNESCO and the United Nations Framework Convention on Climate Change (UNFCCC).
• The Pradhan Mantri Surya Ghar Muft Bijli Yojana, launched in February 2024, aims to provide free electricity to one crore households by subsidizing rooftop solar installations.
• India plans to generate an additional 102 GW from innovative solar installations, such as those over irrigation canals and floating panels.
• Traditional silicon-based solar panels only produce electricity during the day, and battery storage systems can increase costs by 1.5 times.
• MOST systems address this intermittency by storing solar thermal energy in a molecular form, which can be released as heat for various applications like water heating and cooking.
• Unlike conventional solar panels that use red and near-infrared light, MOST molecules absorb wavelengths below 500 nm, in the ultraviolet region.

Scientific/Technical Concepts Involved:

• Molecular Solar Thermal (MOST): A technology that stores solar thermal energy in molecular form using photo-switches for on-demand release.
• Photo-switching: The process where molecules absorb light and undergo a reversible change in their structure, storing energy in the process.
• Isomerisation: A chemical process where a molecule transforms into an isomer, a compound with the same chemical formula but a different structural arrangement.
• 2-pyrimidone: An alkaloid molecule used in MOST systems that converts into its highly strained isomer, Dewar pyrimidone, to store solar energy.