The pros and cons of solar energy

Solar power is the third largest source of renewable energy globally, behind hydropower and wind – but it's the fastest-growing. 

In 2023, three-quarters of new renewable electricity capacity came from solar power, according to the International Energy Agency.

Solar energy refers to power generated by sunlight, captured via solar panels. Most solar energy is photovoltaic (PV) – converting light into electricity – but the sun's rays can also be used to power thermal panels, which directly heat water or other liquids.

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Climate experts are united on the need to transition to renewable energy sources, but the field of solar power is not without its concerns and controversies.

Pro: it's already working

The momentum of solar energy uptake has already passed a "tipping point" towards "irreversible" dominance, according to researchers at the University of Exeter and University College London.

Their study, published in the journal Nature Communications last year, predicted that by the middle of this century solar power "will have come to dominate the [global energy] mix". It credited the technology's wide availability and "economic attractiveness" for creating "a cycle of increasing investments" around the world.

Con: billions of panels need recycling

The 2.5 billion or so solar panels currently installed around the world will start to lose efficiency after 25 to 30 years, said the BBC, yet "specialist infrastructure to scrap and recycle them is lacking". 

With the first wave of solar panels now "approaching retirement", action is needed to create facilities to recycle them effectively.

"It's going to be a waste mountain by 2050, unless we get recycling chains going now," Ute Collier, deputy director of the International Renewable Energy Agency, told the broadcaster.

Pro: improving technology

The efficiency of solar panels has seen "significant progress" in recent years, said The Independent, "primarily boosted by the so-called 'miracle material' perovskite", which consists of calcium titanium oxide.

One of the most persistent concerns over solar panels is their capacity to generate enough energy to cover cloudy spells, but perovskite solar cells "are able to capture about 20 per cent more energy from sunlight than traditional ones made from silicon", said the Financial Times. It's no wonder the material is "the talk of solar energy circles", although production would need to ramp up significantly if they were to become standard on the global market.

Con: vast solar farms

Rooftop solar panels can supply power effectively to individual homes and businesses, but harnessing solar energy on a wider level means massive solar farms.

For instance, the planned Botley West mega farm in Oxfordshire, which would supply energy to an estimated 330,000 homes, would take up about five square miles of countryside. Proposals such as this one are putting "the frontline of the battle to go green… in rural community halls", said Politico.

Botley West has provoked a fierce backlash, from concerns over the impact on wildlife to local residents "grumpy about potential noise and bucolic views being spoiled", the news site said.

Pro: the sky's not the limit

Solar farms in space would be a novel way to avoid protests over spoiled countryside – and they're closer than you might think.

Until a few years ago, the idea would have been "dismissed as science fiction", said Sky News science correspondent Thomas Moore, but now governments and private companies alike are investing in plans to launch specially designed systems of solar panels into orbit.

Solar panels would "capture 13 times more energy in space than they do on the ground", Moore said, so even allowing for energy lost while being beamed back to Earth, "it would still far outstrip solar generation on the ground".

Con: China's dominance

Even as uptake of solar energy increases worldwide, Europe-based manufacturers of solar cells are scaling back production or even going bankrupt because "in some cases 95%" of panels and parts installed in Europe come from China, said Reuters.

Chinese manufacturers offer lower prices than their Western counterparts, but reliance on China raises questions over "cybersecurity and sustainability", as well as labour practices. Almost half of the polysilicon used in solar panel production comes from the Xinjiang Autonomous Region – home to China's Uighur Muslim minority, who are regularly subjected to forced labour.

The European Commission's recent Solar Charter introduced measures designed to "help European clean tech manufacturers compete with foreign suppliers", Reuters said, but still chose to "steer clear of restrictions on cheap panel imports from China".