Technology is changing, costs are falling: how photovoltaics are central to the transition to energy

To achieve carbon neutrality by mid-century and limit global warming to 1.5°C above pre-industrial times, as envisaged by the Paris Climate Agreement, by 2030 the planet will need to install four times as much solar power as it does today. according to the International Energy Agency (IEA).

The good news is that prices have plummeted.

According to a report by IPCC scientists published in early 2022, unit costs for solar fell by 85% between 2010 and 2019, and for wind by 55%.

But “This is possibly the cheapest way mankind has found to produce electricity on a large scale.”said Gregory Nemeth, a professor at the University of Wisconsin-Madison and one of the lead authors of the report.

Solar panels AFP / Jonathan Walter.

Against the backdrop of soaring fossil fuel prices and concerns about energy security caused by the Russian invasion of Ukraine, the development of renewable energy sources has already begun.

According to a BloombergNEF report, global investment in solar projects in the first half of the year increased by 33% compared to last year, to $120 billion. In wind energy, they grew by 16% to $84 billion.

And Joe Biden’s climate plan, due to be passed by the US Congress, has bolstered that momentum by providing $370 billion in public money in tax credits aimed at reducing US greenhouse gas emissions by 40% by 2030 (compared to 2005).

“Mr. Biden’s Plan Will Restore Solar Panel Manufacturing in the United States”was judged by the director of the European Climate Fund, Lawrence Toubiana, in a French daily newspaper. in World Thursday.

According to Nemeth, it is likely that by the middle of the century solar energy alone will account for half of the world’s electricity. “There is a lot of potential,” he says.

French discovery

Solar station in Guignen, western France on December 8, 2020 AFP/Archive / Loic VENANCE.

“Photoelectric effect” – a process that allows you to get electricity from solar radiation – was discovered in 1839 by the French physicist Edmond Becquerel.

The first silicon-based cells were developed in the US in the 1950s, but today the vast majority of solar panels are made in China.

New PV cells on the market are 20% more efficient at converting light into energy than just five years ago, according to the IEA, thanks to new hybrid materials.

Among the novelties are the so-called panels “thin film”, cheaper than silicon cells. They can be “imprints” on all kinds of perovskite crystal ink substrates, a material discovered in the 19th century by the Russian mineralogist Lev Perovsky.

According to experts, this discovery could revolutionize the industry by increasing the number of places where solar energy can be produced. Provided that this new generation of panels wears out less quickly than currently and can last at least 20 years.

Which recent research seems to make possible.

In the journal Science in April, scientists reported success in making perovskite panels as efficient as silicon.

Another study, published in the journal Nature, is betting on semiconductors in “tandem” increase the energy conversion of the spectral range of solar radiation: perovskite for infrared and more carbonaceous material for ultraviolet.


A floating photovoltaic power plant in Piolenc, southern France on July 30, 2019.
AFP/Archive / Gerard JULIEN.

It remains to solve the problem of the night, when there is no solar radiation.

Stanford researchers this year succeeded in creating a solar cell that can generate power at night using the heat given off by the Earth.

“There is a lot of creativity in this industry”notes Ron Schoff, who leads renewable energy research at the Electrical Engineering Research Institute (EPRI) in the US.

One answer to the problem of increasing land use with solar farms, he says, will be double-sided panels: they generate electricity on both sides from sunlight and light reflected off the floor.

Other solutions rely on agrovoltaism, translucent panels for growing crops. In India, panels have been installed on canals for a decade to generate electricity and reduce evaporation.

Consumers can also play a role, Mr. Nemeth said, by changing consumption hours or joining private networks as part of Airbnb’s approach.