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Closing the loop in Energy Sector – Solar Energy

Energy is an essential part of human life. With rapidly increasing energy demands of the modern world, the energy future of the world is arguably an important part of most national and international discussions.

Firstly, the demand for energy has been rapidly ramping up with the increase in population and growth of living standards. Secondly, our infrastructure highly depends on fossil fuels. So, the world is in need of low cost, sustainable energy production in Tera-watt scale with least effects on the environment.

The Sun which is the indirect source of all forms of energy on the planet produces massive amounts of energy and capturing it directly may be a solution for the energy problem. The amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year.

Accompanied by the technological advancements which resulted in around 90% reduction in costs, Solar energy grew by leaps and bounds in the last decade. According to Wood Mackenzie, global annual solar installations grew eight-fold from 16 gigawatts in 2010 to more than 135 gigawatts in 2020.

A cumulative amount of 627 GW of solar power was installed throughout the world by the end of 2019. India’s is one of the top installers in recent years with an installed solar capacity of 37 GW till date, including the recently inaugurated ultra-mega Rewa solar park by Prime Minister Narendra Modi emphasizing self-reliance in the solar power sector. India is also the lowest cost producer of solar power globally, in terms of the country-wise average for the total installed costs of utility-scale solar photovoltaics (PV).

In addition to its large-scale grid-connected solar (PV) initiative, India is developing off-grid solar solutions to meet rural needs; just under 6 million solar lanterns were sold in the country, reducing the need for kerosene. 1.7 million solar-home lighting systems and 46,655 solar street lighting were installed under a national program as of March 2019. (

India has also initiated the International Solar Alliance (ISA) which aims to deploy over 1,000 GW of solar generation capacity globally and mobilize investment of over $1 trillion towards it by 2030. India has also put forward the concept of "One Sun One World One Grid" and "World Solar Bank" to harness abundant cross border solar power on a global scale.

This disruptive clean energy also comes with challenges like any other technologies; The lifetime of silicon (1st generation) solar panel is typically 20-30 years and what happens to a solar panel after its end of life?


End-of-Life Perspective of Materials in the Value Chain

The current lifecycle of solar PV, in general, follows the traditional take-make-dispose model. At the end of its lifecycle, solar panels are generally destined for disposal. It is estimated that solar waste will amount to 80 million tons by 2050. All this will add up to the existing e-waste on the planet. During the last couple of years, this problem has become evident and there is a dire need to research and develop methods and technologies to tackle the panels after the end of life before they start to enter waste streams in large volumes globally.

Good recycling solutions are needed to tackle these complex pieces of technology after its life to recover valuable materials, including silver and silicon. They cannot be allowed to enter landfills as valuable resources go waste and they can even create environmental hazards due to the presence of toxic materials like lead that can leach out as they breakdown.

Although preliminary efforts should be to tackle the PV waste, there should be an increased focus on early lifecycle stages (material selection, design etc.) of the panels to design out waste in the first place and reduce input material, improvise lifetime and design for maximum reparability, reusability and recyclability.

Currently, the markets are dominated by Silicon solar panels but there are numerous other solar technologies in research, development and commercial usage phases which fall under the 2nd and 3rd generations of solar cells.

More than 90% of the solar cells in use are crystalline Silicon ones as they are the most efficient. The newer generations are catching up on the efficiency but have various other benefits from a circular economic perspective. They require less material input and some of them are easily recyclable compared to the Silicon ones.

The thin-film solar technologies in general are more environmentally friendly compared to the silicon wafer ones. Thin-film Cadmium Telluride photovoltaics carry the lowest life cycle impact in terms of energy consumption, waste treatment process, end-of-life dismantling, landfilling and recycling [1]. Organic photovoltaics have the lowest manufacturing costs and are light weighted, transparent and are best suited for low power applications.

Apart from the design and recovery phases, it is even important to concentrate on lifetime extension in the usage phase of the panels – thinking about how to repurpose panels wherever possible, as used solar panels carry higher value and fetch a greater price than the metals and minerals inside them. Unique business models like the product as a service or sharing platforms make renewable energy accessible and increase long term revenues. Product service systems and collaborative consumption models fall under this category. The CIRCUSOL (Circular Business Models for the Solar Power Industry) project by European Commission is funding a range of projects to portray how used panels from rooftops and solar farms can be repurposed.

So, it is important to consider all stages of the lifecycle – design, use and recovery phases to decide among the alternatives and pick the one that benefits over the long run.

Solar energy has amazing potential to power our daily lives especially when a circular model is developed. As a senior scientist at NREL who specializes in sustainability science (Garvin Heath) puts it up “PV is a major part of the energy transition, we must be good stewards of these materials and develop a circular economy for PV modules.” Finally, we must remember,

Positive returns every day the sun shines!

This is the first in the series of articles on Circular economy and solar energy. In the upcoming articles, we will further investigate into the value chain to see how the linear lifecycle of solar products can be turned circular, discussing the benefits and barriers involved.

About the Author

Vivek Manchala (LinkedIn) is a Circular economy enthusiast. He has his undergraduate degree in electronics engineering from Amrita university currently working with Continental Automotive. Solar energy and sustainability are among his primary interests. 


1. Life cycle assessment of most widely adopted solar photovoltaic energy technologies by mid-point and end-point indicators of ReCiPe method' by A. Rashedi & Taslima Khanam; Environmental Science and Pollution Research (2020)




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