Solar electricity is now "the cheapest energy in history. Cheaper than coal, oil or gas energy. This is the remarkable change that's happened in the past five years," says Andrew Blakers, one of a small team of research engineers that has been instrumental in bringing about this transformation. In recognition of his work in developing the PERC (passivated emitter and rear cell) solar photovoltaic energy cell, he and three of his colleagues at the Australian National University (ANU) have been awarded the 2023 Queen Elizabeth Prize for Engineering. As one of the judges on this year's QEPrize said of the victorious PERC technology: "The winners this year stood out because of the importance of proving that we can produce solar voltaic cells that can meet the energy demands of the future. They showed it can be done."
Awarded for ground-breaking innovations that have been of 'global benefit to humanity', the Queen Elizabeth Prize for Engineering is arguably the most prestigious international honour in the sector. Its aim, says its most recent laureate Blakers, is to inspire "a new generation of engineers to create solutions that can help us tackle the biggest challenges faced by humanity, such as climate change". Chairman of the Queen Elizabeth Prize for Engineering Foundation Lord Browne of Madingley says the "QEPrize celebrates the engineers who time and time again solve the impossible and transform our world for the better. PERC solar technology is one of those innovations."
Blakers, who is Professor of Engineering at ANU, says that PERC "is now the most commercially viable and efficient silicon solar cell technology used in solar panels and large-scale electricity production, and accounts for almost 90 per cent of the global solar cell market". In combination with other renewable technologies, it is playing a role in "reducing more than three-quarters of present-day global emissions and reaching net-zero carbon emissions by 2050 – as called for in the Paris Agreement. Solar energy provides a solution that is not only clean and sustainable, but accessible and affordable to the wider public." With worldwide demand for solar growing and global economies increasingly recognising its benefits, the International Energy Agency estimates solar PV capacity will triple over the 2022-2027 period, becoming the largest source of power capacity in the world. Currently, solar is providing about half of new-build electricity generation capacity worldwide.
There's never been a Nobel prize for engineering – although several notable engineers have scooped the accolade in different fields – which has led to the general consensus that the Queen Elizabeth Prize for Engineering is the nearest thing we have to an equivalent. Blakers agrees, and is understandably aware of the scale of the honour, while taking pains to draw attention to the fact that such high-profile recognition is for sustained scientific collaboration. He's not just talking about the colleagues he worked alongside – Martin Green, Aihua Wang and Jianhua Zhao – but also the entire solar community that has, in contrast to other research sectors, shared its ideas widely. The PERC team, says Blakers, haven't patented their work in an attempt to encourage further work in the field.
Blakers maintains that the development of solar photovoltaics has been an incremental "team effort" right from the early days of the technology in the 1960s. "There hasn't been one of those Theory of Relativity breakthroughs that Einstein had. It's been a long succession of small steps by many, many people." He explains it was by collective effort that they first took silicon solar cells into space on satellites, and also out into remote areas. "That was a big thing in Australia because solar panels do a lot better than diesel gensets when you're 500km from the nearest town." From these initial applications, solar power has "turned into a global juggernaut that is pushing fossil fuels into oblivion". It's been a team effort by electrical, mechanical, materials, design and chemical engineers, as well as physicists "and everybody else in between". What this widespread co-operation has achieved, says Blakers, is to bring "something that costs thousands of dollars per square centimetre of solar cell down to thousands of square centimetres for a dollar". That trend is "what's sweeping fossil fuels out of the energy market".
The 67-year-old Australian professor has watched or taken part in most of the evolutionary timeline of photovoltaic solar energy, from its early days of being regarded as a fringe technology to the point where harnessing the power of the Sun is underpinning the large-scale production of low-cost electricity. But, says Blakers, "it doesn't really matter when you come into the industry. Because of its exponential growth, you're always in on the ground floor. If you came into this a decade ago, then the industry's now ten times bigger. I came into the area in 1979 and the market is 10,000 times bigger – probably a lot more – than it was. It's just mind-boggling growth in a small number of years."
Looking back over his career, Blakers identifies three phases in the evolution of solar. "At the start there was this idea that solar energy is a joke. Sure, if you're out in the middle of the Indian Ocean somewhere, solar panels are the way to go. But as for real energy that can run a smelter or an electricity system... you need massive subsidies. It's just not going to happen." Here the professor breaks off to imitate the sarcastic laughs of the detractors that were many and vocal at the dawn of the technology. "Then about five years ago, there was this massive change when the gas and coal industries recognised that solar was a real threat." This was when the tone changed from a be-my-guest attitude to the rhetoric of "hostility, misinformation, outright lying and concerted efforts to slow solar down". But now, says Blakers, "at least in Australia, there's pretty much universal acknowledgement that solar and wind have hands-down won the global energy race, and by the end of this decade will constitute 80-90 per cent of the energy mix".
Blakers sees Australia as a model for how the rest of the world can move towards a renewable future, describing the country as "the global solar pathfinder. It is generating twice as much solar energy per capita than any other country. Australia is way out in front, and it's all non-subsidised in a completely open market. The reason we are so far ahead is that we have a relatively free electricity market that anybody can hook into with their solar or wind farm as long as they meet a few tech specs. Most other countries don't have that. It has been a remarkable change. Every state and territory government, and the national government, understands that the faster we get to 100 per cent renewables, the lower will be our electricity prices. The world is going to follow the Australian path very fast because nobody really wants to burn coal, oil and gas anymore."
At this point, he digresses on the subject of Russia's aerial attacks on Ukraine's critical national infrastructure that has concentrated on power generation facilities. Blakers contends that the major supply disruptions caused by the bombardment would have been more manageable in a distributed renewable network. He thinks there are now "a lot of people" waking up to the idea that if you have systems "comprising thousands of wind farms and millions of solar panels spread across the entire continent with a strong network joining them all together, you've got to work hard to knock out even a few per cent. But take out one fossil or nuclear power station and you've lost 10 per cent of your electricity." Another advantage, says Blakers, is that territories implementing national renewable strategies will rely less on importing "other people's energy. You make your own."
Discussing how PERC has made such a contribution as a game-changer, Blakers explains the problem with designing solar cell for commercial use is the trade-off between "making a really efficient solar cell that no-one can afford to buy, or a really cheap one that you can't afford to mount on structures because it is so inefficient". What researchers such as himself have worked towards, he continues, is a "sweet spot", which is where the PERC cell finds its niche. "In a nutshell, traditional solar cells didn't worry about what was going on at the back of the silicon wafer. With these old-style cells, all the engineers really worried about was what was going on at the front. PERC allowed optimisation of both surfaces in a cost-effective way, and for the past decade, it has provided affordable-efficiency potential in that sweet spot." He speculates that in the next decade, it's likely that another technology will push PERC out of the equation, "but at the moment it is completely dominant".
One of the misconceptions Blakers has to deal with is the attitude that Australia is better suited to renewable adoption than other regions due to geophysical factors such as latitude, climate and area, while small northern islands such as the UK enjoy none of these advantages. But he sees no reason why the mix of solar and wind can't be applied as a universal renewable energy solution. "Yes, it can be," he says, reminding me that most Australians live at moderate latitudes – the planet's subtropical and temperate zones lying between the two tropics and the polar circles – a characteristic shared with 80 per cent of the global population. "For these six billion people, the summer-winter ratio of solar is less than two-to-one, meaning that solar works well in winter as well as summer."
For northern Europe, north-east Asia and North America, "that ratio can be as high as six-to-one, which means that in winter you're not getting much solar. But the fact is that wind energy works much better at high latitudes generally." In the case of the UK and Europe, Blakers elaborates, there is "unlimited offshore wind around Britain and further south you get a lot of sun. The obvious thing to do here is to connect north to south so that the winter wind energy goes south while the summer sun energy goes north. Britain won't go solar in a big way. But it has awesome offshore wind in the Irish Sea and the North Sea. Britain has got energy coming out of its ears – but it's not solar.
"That's the way you make the system work," says Blakers, adding that you also need wide-area transmission to smooth out local weather and the third factor of storage. The important point about the system, he continues, is the technology required to make it work already exists: "The world can readily get rid of 80 per cent of its greenhouse gas emissions using off-the-shelf technology already in production in vast quantities." The solution is staring us in the face, says Blakers. It's just a question of promoting teamwork between the two technologies that convert the plentiful natural resources of sunlight and wind. "Everybody has got solar and/or wind. Which means that everybody can benefit from a cheap energy system based on solar, wind and a modest amount of storage."
Reflecting on why he's never bothered to patent his work on solar cells, Blakers says: "When we published our work, we decided not to because it just seemed that the 20-year life of the patent would expire before the technology hit the commercial big time: so, what was the point?" But perhaps more importantly from the perspective of getting alternative energy into the mix, Blakers felt that "the sooner this technology gets out and gets used the better. There's not many of us," he says of the renewable research and development community, "who are in this for the intellectual challenge. All of us are in this to save the planet."
