The future of solar energy looks bright
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Will solar energy take over the world? The past few years have seen a frankly staggering acceleration in the pace of its adoption, with total generating capacity doubling between 2022 and 2024, to supply as much as 7 percent of the world's electricity. How high can this figure be?
In the first six months of 2025, wind and solar power together passed a historic milestone, generating more electricity than coal for the first time and making renewables the world's leading source of electricity. The driving force behind this “major turning point” in the energy transition, as described by UK think tank Ember, is the rise of solar power. It accounted for 83 percent of the total increase in global electricity demand in 2025. Amber's analysis showsand has been the largest source of new electricity in the world for three years in a row.
Solar's secret weapon? How cheap is it? This is the cheapest electricity in the world: the cost of installing a solar system has fallen in price by 90 percent over the past 15 years. “Right now, silicone panels cost the same as plywood,” says Sam Stranks at Cambridge University.
In other words, we have an abundant and cheap source of electricity that can be quickly built almost anywhere in the world. Is it fantasy to imagine that one day solar energy will be able to power everything?
At the most fundamental level of solar energy delivery to Earth almost limitless. Even if we take into account the efficiency of modern solar panels, it would require about 450,000 square kilometers of land to supply all of the world's energy needs with solar energy. UK think tank Carbon Tracker's 2021 report estimates. That's just 0.3 percent of the world's land mass.
Kingsmill Bondone of the report's authors, now at Ember, says that while there are “trade-offs” when it comes to land use (for example, solar energy can compete with agriculture), “there is plenty of room for most countries to adopt these technologies.”
New generation of panels
The question then arises: what is stopping solar energy from completely taking over the global energy supply? The first question is a question of efficiency. Silicon photovoltaic panels, which make up the majority of the global solar energy market, currently convert about 20 percent of solar energy into electricity. By comparison, hydroelectric power plants convert 90 percent of potential energy into electricity, wind turbines convert about 50 percent, and fossil fuel power plants convert 30 to 40 percent.
In real terms, this means that you need many more solar panels to provide the same amount of energy that you could get from other sources. That's why solar energy companies and scientists are working hard to try to get greater efficiency gains out of solar panels, in the hope that increased efficiency will bring the double benefit of solar power: even lower system costs and less demand on the land.
However, crystalline silicon panels are approaching the limit of the efficiency they can achieve: best-in-class cells are now about 25 percent efficient. “The practical limit for crystalline silicon content is probably about 28 percent,” says Jenny Nelson at Imperial College London.
Increasing efficiency will require a move to a so-called tandem solar cell, which uses a second semiconductor to increase the amount of energy the cell can extract from the solar spectrum. Tandem silicon perovskite cells are seen as the most promising option, with a theoretical efficiency limit of about 50 percent. Real tandem panels won't achieve that level of efficiency, but can achieve efficiencies of 35 to 37 percent, Stranks said.
After many years of research, the first tandem silicon perovskite solar panels were created. just starting to go into commercial productionand they need to be tested by the industry to see how long they maintain their performance in real-world conditions. But Stranks is optimistic about their potential. He estimates that in 10 years they will become the dominant technology in the market. “At first glance, they don't look much different from those installed on a roof or on the street, but they produce 50 percent more energy than modern panels,” Stranks says. “It's a big change.”
According to Stranks, the increased efficiency will not only further reduce costs, but will also open up new deployment opportunities. For example, highly efficient panels could provide solar roofs on electric vehicles, allowing their batteries to charge throughout the day. The stored energy could then be used for transportation or discharged home for use in the evening, he said.
Solving the storage problem
Such an innovation could help solve another serious problem associated with solar energy: its inconsistency. The sun, of course, does not shine all the time. For sunbelt countries, including India, Mexico and many African countries, this is not a problem because the sun shines almost all year round and batteries can be used to store excess energy during the day for use in the hours after dark. This solar and storage system is becoming increasingly cost-effective, with the cost of lithium-ion batteries falling 40 percent in the last two years alone. according to BloombergNEF.
“Ultimately, the only advantage that fossil fuels have over sunlight as a source of electricity is their ability to be stored,” Bond says. “And suddenly the storage problem was solved 90 percent of the time with one technology: the battery.”
But for countries further north, where winter days are short and grey, things are different. “[Solar] “is an incredibly, amazingly good source of energy with zero pollution and a quick return on energy investment – it just ticks all the boxes,” says Andrew Blakers at the Australian National University in Canberra, Australia. “Unless you live in Northern Europe, Northeast Asia or the Northeastern US, where there is a lot of sun in the summer and little in the winter. [solar] simply the best.”
In countries that suffer from long, dark winters, wind power could make up much of the shortfall, Blakers said. But it will also require energy storage solutions that can store electricity for weeks or months. Such “off-season storage” is still in its infancy, and few solutions work on a commercial scale. But they pumped hydropower, hydrogen and compressed air storage everyone could give the answer to this riddle. Blaker's forecast? “Batteries take care of the short term, hydroelectric power takes care of the long term.”
Political headaches
If anything, efficiency and storage are problems that are easy to solve. “I think the bottlenecks probably come from politics, policy consistency, regulation, vested interests from other industries,” Nelson says.
A prime example is the climate-skeptic Trump administration in the US. Earlier this month, federal officials canceled a massive proposed solar power project in Nevada that would have been one of the largest schemes in the world and just the latest in a series of actions to cut solar financing programs and block projects.
But Bond believes the move to renewables is now virtually unstoppable given their economic advantages over traditional generation sources. “Incumbents may hold back solar development in individual countries, in individual projects and in individual years,” he says. “The current Trump administration is doing everything it can to slow down the current deployment of renewable energy. But all that really means is that they will then fall behind in the global race to adopt advanced technologies.”
Blakers agrees, adding that solar energy may be the only way to meet rapidly growing demand for electricity from artificial intelligence data centers. “Even in the US, it's hard to imagine shutting down solar power, even by a determined federal government, because a lot of states like it, and it's by far the fastest way to get a lot of power,” he says.
Another major obstacle to clean energy is logistics. Existing power grids need to be retooled to cope with the huge and erratic supply of electricity coming from new areas. A more flexible power system, able to cope with surges in output and even adjust electricity demand in response, will help maximize the use of green energy. But building these networks of the future costs money. In the UK alone, energy companies plan to spend £77 billion over the next five years retooling the electricity network to cope with the shift to wind and solar power.
In low-income countries where grid networks are not yet as comprehensive, countries can move more quickly to build renewable energy infrastructure from the start, allowing renewables to penetrate deeper into the energy supply. The 10 so-called BRICS countries – Brazil, China, Egypt, Ethiopia, India, Indonesia, Iran, Russia, South Africa and the United Arab Emirates – now together account for more than half of the world's electricity production from solar power. according to Amber.
The broader challenge for countries is to electrify more of their energy needs, from heating to transport. Such progress is critical to reducing fossil fuel use in other parts of the world economy. As Nelson says, “If we want to decarbonize the planet, we need to electrify first.” Here again, low-income countries outperform higher-income countries. China's electricity share of final energy consumption reached 32 percent in 2023, far exceeding the 24 percent electrification rate in the United States and wealthier European countries. says Amber.
A sunny future?
Despite this year's success, the technical, logistical and political challenges described above may slow the adoption of solar energy in some countries in the short term. Earlier this month, the International Energy Agency predicted that renewable energy will more than double by the end of the decadebut doesn't match international goal to triple capacity by the same date. The agency said policy changes in the U.S. and challenges to integrating solar energy into the grid are hampering the expansion of renewable energy capacity.
But energy market experts are confident that solar energy will dominate the world's energy supply by mid-century and beyond. “By the end of this century, it will be abundantly clear that we will get all of our electricity from renewable sources, the vast majority of which will be solar,” says Bond, estimating that by 2100, up to 80 percent of global electricity production will come from solar power. In addition, at least 80 percent of total global energy demand will be electrified, he expects.
All barriers related to politics, energy storage and infrastructure will be removed to start the green energy revolution. “The human condition is to turn energy into things,” Bond says. “We use energy for everything. And then suddenly we found this cheap, universal source of energy – of course we're going to find out.”
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