Over the past century, solar energy activist Jaideep N. Malaviya points out, global temperatures haven risen by 1.5°F (almost 1°C) human activities have released large amounts of carbon dioxide and other greenhouse gases (GHG) into the atmosphere. Most of the GHG come from burning fossil fuels to produce energy, while deforestation, industrial processes and some agricultural practices also emit gases into the atmosphere.
GHG - mainly CO2, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, and sulphur hexafluoride - act like a blanket around Earth, trapping energy in the atmosphere and causing it to warm. “Build-up of GHG can change the earth's climate and result in dangerous effects to human health and welfare, and to ecosystems,” says Malaviya, a professional researcher, consultant and trainer in solar photovoltaics (PV) and solar thermal who is the secretary general of the Solar Thermal Federation of India (STFI).
While renewable energy sources like solar and wind are rapidly advancing to fulfil the energy demand and are likely to become substitutes for fossil fuel-based energy in future, the production of solar PV cells has a carbon footprint. The energy required to make a solar panel from mining basic raw materials is recovered in just two years; while the recycling of solar panels further aids the fight against climate change.
How much GHG is avoided from solar power? Each megawatt-hour (MWh) of electricity generated from conventional sources creates approximately 90 kg of CO2. A 1 MW solar system in India, on the other hand, will yield an average of 1,600 MWh annually, reducing around 150 tonnes of CO2 emissions every year. Taking into account the two years to pay off the embedded energy in the panel, such a 1 system will have a net saving of around 3,000 tonnes of CO2 in 25 years.
The manufacture of a complete solar energy system – comprising the solar cells, glass, aluminium frame, laminate, mounting and cabling, inverter, and takeback for recycling – has a carbon footprint of 21 to 29 kg of CO2 per MWh. Against this, coal-based power has a carbon footprint between 500-600 kg per MWh, Malaviya explains. This is more than 20 times as much.
Of the government’s target of 450,000 MW of renewable energy by the year 2030, solar energy is set to contribute about 70 per cent - or 300,000 MW. But every MW of solar panel weighs approximately 50 tonnes. At the end of their life, these panels would create 15 million tonnes of waste by 2050. This, he points out, would cover 6,000 km of the road if stuffed in standard 40-foot containers.
Recycling them, on the other hand, would recover almost 80 per cent of raw material for use in making new panels. This will result in overall CO2 abatement of 360 billion tonnes of CO2) in their lifetime. The new 3R’s of solar panel are recycling will thus be Recycle, Reduce and ReGenerate.