Solar technology: a powerful force to combat climate change

Developing the world’s most commercially viable solar cell technology

In 1974, UNSW Scientia Professor Martin Green completed his PhD in Engineering Physics and joined UNSW as a lecturer in microelectronics. At the time, the US government started a program at NASA to improve the voltage from a silicon solar cell – previously only used on spacecraft – to harness the sun’s energy to generate electricity. Prof. Green decided to funnel his expertise into this effort as he saw the potential for positive societal impact by helping to reverse the effects of global warming and climate change caused by burning fossil fuels to generate energy.

He also knew solar technology and infrastructure would need to be manufactured cheaply to ensure widespread adoption and to have meaningful impact. His pivotal leadership in developing solar cell technology and educating his students – the future generation of the workforce – have earned Prof. Green an extensive list of global awards and a special nickname, “Father of modern photovoltaics”.

When he arrived at UNSW, Prof. Green assembled a team that surpassed NASA’s silicon solar cell voltage targets using a structural technique based on a quantum mechanical tunnelling approach he’d studied during his PhD. By the start of the 1980s, Prof. Green and his team then began to develop all the other components required to make a silicon solar cell that would incorporate their world-leading voltage technology. His next goal was to make solar cells with the best silicon cell energy conversion efficiency in the world. By maximising the electricity produced from sunlight falling onto solar panels, he could reduce the area of the panels and cut installation costs. Prof. Green knew this was essential to ensure commercially viability and to have any hope of solar energy helping to slow the rate of global warming. 

Prof. Green and his team achieved their first and second world records for silicon cell efficiency in 1983, making the first silicon solar cells over 18 per cent efficient by today’s standards. That same year, he conceived the Passivated Emitter and Rear Cell (PERC), a new cell structure he developed with his team at UNSW. Prof. Green estimated PERC’s maximum practical limit of 25 per cent efficiency, which the team achieved in 1999. Prof. Green’s research group at UNSW has held the global record for efficiency for 30 of the past 40 years, with PERC underpinning the recent exponential growth in high performance, low-cost solar electricity. 

Training the solar workforce 

Another major contribution of Prof. Green’s to the field of affordable solar energy is training the world’s solar entrepreneurs and future workforce. He co-founded the School of Photovoltaics at UNSW Engineering, and he has supervised more than 120 PhD students, many of whom went on to establish solar cell manufacturing in China.  
 

Responsible for 90% of solar panels produced globally in 2021–22 

According to the International Energy Agency, solar is the “cheapest option for new electricity generation in a significant majority of countries worldwide.” UNSW, through the groundbreaking work of Prof. Green, can claim credit for more almost 90 per cent of the solar panels that were produced in the world in 2021 and 2022. 

Prof. Green’s 12th PhD student Zhengrong Shi founded China’s first private cell manufacturing company Suntech in 2001. It was the first private Chinese company to list on the New York Stock Exchange in the largest tech float of 2005, raising $US400m. Following this path, a further 10 companies were listed on the US exchanges between 2002–2010 and six of these are now the largest manufacturers in the industry today. Of these six companies, five had founders, chief technical officers, or senior leaders that were part of Prof. Green’s research group.  Strong competition between these companies, and those which followed, has rapidly driven down solar prices. 
 

A powerful tool to combat the effects of climate change

PERC solar cells were introduced to the global market in 2016, cutting the costs of solar technology and infrastructure further. It’s estimated that since PERC began seriously challenging for commercial market share in 2016, it has reduced solar prices by almost 50 per cent compared to what they would have been without its introduction. 

By providing a clean and renewable energy alternative to the global community, solar energy technology developed under Prof. Green at UNSW is arguably the world’s most powerful tool to combat the effects of global warming and climate change.