In the 1980s, a global race was underway: to find a more efficient way of converting energy from the sun into electricity.
Some 30 years ago, our research team at the University of New South Wales (UNSW) came up with a breakthrough, called the PERC silicon solar cell. The cells have become the most widely deployed electricity generation technology in terms of capacity added globally each year – comfortably exceeding wind, coal, gas, hydro and others.
Curious Kids: how do solar panels work?
PERC stands for Passivated Emitter and Rear Cell. By the end of this year, PERC technology will be mitigating about 1% of global greenhouse gas emissions by displacing coal burning. Assuming that its rapid growth continues, it should be reducing greenhouse gas emissions by 5% by the mid-2020s and possibly much more in later years.
The terrible bushfires in Australia this summer, enhanced by the hottest and driest year on record in 2019, underline the need for urgent reductions in greenhouse gas emissions. By far the most effective way is driving coal out of electricity systems through very rapid deployment of solar and wind.
Soon, our Aussie invention will be generating half the world’s solar power. It is a pertinent reminder of Australia’s capacity for finding transformative technical solutions to address climate change. But we need the right government support.
An Aussie invention
Solar cells convert sunlight directly into electricity without moving parts. More efficient solar cells generally produce cheaper electricity because fewer solar cells, glass covers, transport, land and support structures are needed for a given solar power output.
By the early 1980s, the best laboratory cells around the world had reached 17% efficiency. This means that 17% of the sunlight was converted to electricity, and the rest (83%) of the solar energy was lost (as heat).
During the 1980s, our research team at UNSW led by Martin Green and myself created a series of world-record-efficient silicon solar cells. We reported 18% efficiency in 1984, 19% efficiency also in 1984, and the important milestone of 20% efficiency in 1986.
This new, more efficient cell was better than the old ones because we eliminated some defects in the silicon crystal surface, which led to lower electronic losses. The PERC design also enabled us to capture the sunlight more effectively.
In the 1990s, further improvements to laboratory PERC cells were made at UNSW, leading to cells in the 24-25% efficiency range. The global silicon solar cell efficiency record remained at UNSW until recently.
There was a 25-year gap between development of the PERC cell and its rapid commercial adoption, which began in 2013. During this time, many people worked to adapt the PERC design to commercial production.
PERC cells are more efficient than previous commercial cells. Strong incentives for more efficient cells have recently arisen due to the continually falling share of cell costs as a proportion of total solar power system costs (including transport, land and mounting systems).
The big benefits of solar
Currently, solar power constitutes more than 40% of net new electricity generation capacity additions, with fossil, nuclear, wind, hydro and other renewables making up the balance.
Solar is growing faster than the other electricity generation technologies. Over time, as fossil-fuelled power stations are retired, solar (and wind) will dominate electricity production, with consequent large reductions in greenhouse gas emissions.
This year, enough PERC solar modules will be sold to generate 60-70 gigawatts of power. According to projections, PERC will reach three quarters of annual solar module sales in the mid-2020s, enough to match the generation capacity additions from all other technologies combined.
About A$50 billion worth of PERC modules have been sold to date. This is expected to reach several hundred billion Australian dollars later this decade.
Our position as a global leader in renewables installation is uncertain because the Renewable Energy Target, which was achieved in 2019, has not been extended.
With supportive policy, such as facilitating more transmission to bring solar and wind power to the cities, Australia could greatly increase the speed at which wind and solar are deployed, yielding rapid and deep cuts at about zero-net cost.
Such policy would entail stronger and sustained government support for renewables deployment, and research and development of new technologies.
Solar energy is vast, ubiquitous and indefinitely sustainable. Simple calculations show that less than 1% of the world’s land area would be required to provide all of the world’s energy from solar power – much of it on building roofs, in deserts and floating on water bodies.
Solar systems use only very common materials (we could never run out), have minimal need for mining (about 1% of that needed for equivalent fossil or nuclear fuels), have minimal security and military risks (we will never go to war over solar access), cannot have significant accidents (unlike nuclear), and have minimal environmental impact over unlimited time scales.
Australia is making major contributions to mitigating climate change both through rapid deployment of wind and solar and technology development such as our PERC cells. But with better government support, much more can be done – quickly and at low cost.
You’re scrolling through your phone and transfixed by yet more images of streets reduced to burnt debris, injured wildlife, and maps showing the scale of the fires continuing to burn. On the television in the background, a woman who has lost her home breaks down, while news of another life lost flashes across the screen.
You can’t bear to watch anymore, but at the same time, you can’t tear yourself away. Sound familiar?
We’ve now been confronted with these tragic images and stories for months. Even if you haven’t been directly affected by the bushfires, it’s completely normal to feel sad, helpless, and even anxious.
Beyond despairing about the devastation so many Australians are facing, some of these emotions are likely to be symptoms of “eco-anxiety”.
If you’re feeling down, you’re not alone
Research on previous bushfire disasters shows people directly affected are more likely to suffer mental health consequences than those who have not been directly affected.
After Black Saturday, about one in five people living in highly affected communities experienced persistent post-traumatic stress disorder (PTSD), depression or psychological distress.
Recognising this as a critical issue, the Australian government has announced funding to deliver mental health support to affected people and communities.
But living in an unaffected area doesn’t mean you’re immune. In addition to contending with rolling images and stories of devastation, we’ve seen flow-on effects of the bushfires reach far beyond affected areas.
For example, schools and workplaces have been closed, people have been forced to cancel their summer holidays, and sports matches and community events have been called off. This disruption to normal activities can result in uncertainty and distress, particularly for children and young people.
What is eco-anxiety?
Distress around the current fires may be compounded by – and intertwined with – a pervasive sense of fear and anxiety in relation to climate change-related events.
The American Psychological Association defines eco-anxiety as “a chronic fear of environmental doom”.
While concern and anxiety around climate change are normal, eco-anxiety describes a state of being overwhelmed by the sheer scale, complexity and seriousness of the problems we’re facing. It can be accompanied by guilt for personal contributions to the problem.
The Australian bushfires may have signalled a “tipping point” for many people who held a passive attitude towards climate change, and even many who have held a more active view of climate denialism. In the face of current circumstances, the crisis of climate change now becomes almost impossible to ignore.
While eco-anxiety is not a diagnosable mental disorder, it can have significant impacts on a person’s well-being.
Whether you think you’re suffering from eco-anxiety or more general stress and depression about the bushfires, here are some things you can do.
We’re pretty resilient, but support helps
We’re now living with the environmental consequences of a changing climate, and this requires people to adapt. Fortunately, most of us are innately resilient and are able to overcome stress and losses and to live with uncertainty.
We can enhance this resilience by connecting with friends and family and positively engaging in our communities. Making healthy choices around things like diet, exercise and sleep can also help.
Further, supporting those who are vulnerable has benefits for both the person giving and receiving assistance. For example, parents have a critical role in listening to their children’s concerns and providing appropriate guidance.
Become part of the solution
Seeking to reduce your own carbon footprint can help alleviate feelings of guilt and helplessness – in addition to the positive difference these small actions make to the environment.
This might include walking, cycling and taking public transport to get around, and making sustainability a factor in day-to-day decisions like what you buy and what you eat.
Joining one of the many groups advocating for the environment also provides a voice for people concerned about the changing climate.
Finally, there are many ways you can provide assistance to bushfire relief efforts. The generosity shown by Australians and others internationally has provided a sense of hope at a time when many are facing enormous hardship.
Seeking professional help
Some people, particularly those living with unrelated psychological distress, will find it harder to adapt to increased stress. Where their emotional resources are already depleted, it becomes more difficult to accommodate change.
Although we don’t yet have research on this, it’s likely people with pre-existing mental health problems will be more vulnerable to eco-anxiety.
If this is you, it’s worthwhile seeking professional help if you feel your mental health is deteriorating at this time.
Whether or not you have a pre-existing mental health disorder, if you’re feeling depressed or anxious to a degree it’s affecting your work, education or social functioning, you should seek advice from a health professional.
Evidence-based psychological interventions like cognitive behavioural therapy reduce symptoms of anxiety and depression, improving mental health and well-being.
If this article has raised issues for you, or if you’re concerned about someone you know, call Lifeline on 13 11 14.
Bushfires this season have left an estimated 1 billion dead animals in their wake, their carcasses dotting the blackened landscape.
The carcasses have already been flagged as a potential biosecurity threat, and the Australian Defence Force is tasked with collecting and burying the dead in mass graves.
There’s logic in this. Carcasses can harbour nasty diseases such as botulism that threaten human, livestock and wildlife health. They also provide food for invasive pests like feral cats and red foxes.
But carcasses can play a positive role as landscapes recover from fire, providing rich nutrients for other native animal, microbial and plant species.
The Morrison Government has announced a A$50 million package to help wildlife and habitat recover from the fires, and yesterday met leading wildlife experts and environment groups to get advice on the recovery process.
We suggest this process should examine carcass disposal methods other than burial, such as composting – effectively “recycling” the dead. It should also involve monitoring the carcasses that remain to understand both their positive and negative roles in fire-ravaged areas.
The positives: carcasses feed the living
Carcasses feed a range of native animals, including goannas, wedge-tailed eagles and dingoes. Post-fire, they can provide an alternative source of food for struggling native predators and pollinators. And feeding hungry predators with carcasses could redirect them away from vulnerable prey.
Carcasses also feed insects such as flies, ants, beetles, and their larvae, and support important ecological processes such as pollination.
As they decompose, nutrients leach from carcasses into the surrounding environment and create “halos” of greenery in the landscape, where vegetation thrives around carcass sites. Their influence on soil and plant communities can last for years.
The negatives: spreading disease and sustaining feral animals
Carcasses are home to bacteria that help break down animal tissues. But some carcasses also harbour harmful pathogens that bring disease.
For a disease outbreak to happen, the animal must generally have already been carrying dangerous infectious agents, like Anthrax or the Hendra virus, before they died. And many of these pathogens will not survive long on dead hosts.
Leaving carcasses out in the open can also feed introduced predators such as feral cats and red foxes, putting small native animals at risk. Some weeds thrive in the nutrient-rich soils around carcasses too.
Introduced insects like the European wasp, which appeared en masse following fires in Kosciuszko National Park, also take advantage of carcass resources. These wasps are highly aggressive and attack and kill other native insects.
How long does a carcass stick around?
We know very little about the ecological role of carcasses in fire-affected areas, and it’s important that more research is carried out.
We know burnt animals can decompose faster than other carcasses and harbour different types of insect scavengers.
However the recent fires are likely to have wiped out entire scavenger communities, including larger scavengers like dingoes and eagles, that help to clean our landscapes of dead animals.
The effects of this are unknown, but could mean that carcasses stick around in the environment for prolonged periods, even months.
Finding the right solution to a grisly problem
As climate change accelerates the number of natural disasters and mass animal deaths, more thought and planning must be put into carcass management.
In Australia, carcasses are often dealt with by not dealing with them: they’re left to rot. This happened for almost 100 feral horses that died last year at an empty water hole during a heatwave.
Animals culled in national parks and on farmlands are also often left to decay, untouched, as are the many dead animals that commonly line our country roads. But in landscapes where feral species are common, or where livestock or people are likely to encounter carcasses, leaving them alone isn’t the best option.
Carcasses are more often buried following disease outbreaks or when livestock die. We saw this during the 2019 Queensland floods, where thousands of drowned cattle were buried in mass graves.
Burial is a relatively inexpensive, fast and effective method of dealing with the dead. But it must be done carefully to avoid polluting groundwater sources and causing nutrients like nitrogen to build up.
Burying carcasses can also be compared to sending rubbish to the tip. Breakdown will be slow, and no useful end product is created.
A more useful option
An alternative option is to “recycle” carcasses by composting them. Composting can accelerate the decomposition of animal tissues and is environmentally friendly, capturing nutrients.
Composting kills most pathogens, whereas burial just moves the problem underground. It also suppresses smelly odours and doesn’t attract scavengers. The usable organic material resulting from the composting can also be applied to nutrient-poor soil.
Composting can be time-consuming and hard to get right. It requires careful monitoring of temperature and moisture content to ensure all disease-causing pathogens are killed, and odours are suppressed.
There’s also a “yuck” factor and the public would probably need convincing for the method to be widely adopted.
But whatever option we choose, it’s clear there’s more we can do with carcasses than simply burying them.
Emma Spencer, Ph.D. student, University of Sydney; Chris Dickman, Professor in Terrestrial Ecology, University of Sydney; Philip Barton, Honorary Senior Lecturer, Fenner School of Environment and Society, Australian National University, and Thomas Newsome, Lecturer, University of Sydney