At the Smart Energy Event held in late August at the Energypolis Campus in Sion, Christophe Ballif, a professor at EPFL and a recognized expert in photovoltaics at CSEM, delivered a candid assessment of the global energy transition. Amid misinformation, technological advances, and structural challenges, his presentation set the record straight on what we can realistically expect from solar energy. In his view, the transition remains entirely possible with renewable energy, while nuclear power remains the worst possible option.
To understand what’s at stake, we must first look at the global figures. “We currently consume 186,000 TWh of energy, with growth of 2% per year, driven in particular by China, India, and Africa. The problem is that 80% of this energy still comes from fossil fuels, compared to just 20% from decarbonized sources,” he noted. The challenge is therefore clear: to make this large share of fossil fuels—which still dominates the global energy mix—carbon-neutral.
Christophe Ballif did not hesitate to point the finger at certain actors who are hindering the transition. “There is a fossil fuel lobby, as well as countries that depend on oil. It’s a constant battle against misinformation. Many influencers are playing into the hands of the oil lobbies by simply ignoring renewables,” he said.
Nuclear Power: A False Solution on a Large Scale
When asked about the role of nuclear power in the energy mix, the expert was unequivocal. By 2050, approximately 250,000 TWh of energy will be needed, which means tripling electricity production to reach 100,000 TWh. “To achieve this with nuclear power alone, we would have to build the equivalent of 13,000 power plants, each with a capacity of 1 GW. This is simply impossible to implement from a technical standpoint. Nuclear power can make a contribution locally, but it can only be a secondary solution. In the energy transition, nuclear power is nothing but noise,” he declared.
According to him, the system can function without relying heavily on nuclear power, provided that daily storage is managed effectively—particularly through pumped-storage hydroelectricity and batteries. “In Europe, the system is already working well because wind and solar power complement each other. Natural gas and other fossil fuels remain useful as a backup for emergencies,” he explained.
Costs that have plummeted
One of the strongest arguments in favor of renewable energy remains economic. “One square meter of solar panels currently costs 22 francs for the imported materials alone, which works out to 0.4 centimes per kWh. For gasoline, excluding taxes, the cost is 25 centimes per kWh. Solar power is therefore significantly cheaper,” he explained.
An impressive installation rate, but still insufficient
Every day, 2 GWh of solar panels are installed worldwide, mainly in China but also in many other countries. By 2025, the equivalent of 170 nuclear power plants had been installed in solar and renewable energy capacity. “And yet, we’ve only met 2% of global demand. We’d need to double or triple current renewable energy production to truly reverse the trend. Every country must do its part,” insisted Christophe Ballif.
China’s Central, and Ambiguous, Role
The professor spoke at length about China’s dominant position in the production of renewable energy technologies. “We need to invest heavily to set up production lines across the entire value chain, whether for solar panels or batteries. During the COVID years, China made these investments and now has considerable production capacity. Thanks to China, we have what it takes to save the world in 30 years.”
This situation can also be attributed to the Chinese real estate crisis, which has prompted banks to shift a massive amount of their lending toward the renewable energy industry. “In China, there is now far too much production capacity. As a result, costs are falling and quality is rising, amid fierce competition between companies and regions. That is why China remains unbeatable in this area.”
But this Chinese dominance is also creating geopolitical tensions. “China, which needs to export, is becoming the enemy of oil-producing countries, and the United States is helping them,” noted Christophe Ballif, while emphasizing that in Europe, there is strong pressure on companies to maintain their own production capacity in the face of Chinese dominance.
Batteries: A Real Game-Changer
When it comes to energy storage, the progress has been just as spectacular. “The drop in battery costs is a real game-changer, especially if we can increase the number of charge-discharge cycles. We’re now talking about one cent per kWh stored. These are opportunities that simply didn’t exist a few years ago.”
On the sensitive issue of resources, Christophe Ballif sought to reassure listeners. “There are enough materials available to achieve the energy transition using solar and other renewable energy sources. Substitutions are possible, and engineers always find solutions.” He also highlights a major geopolitical advantage. “These materials are much more evenly distributed across the globe than oil is. That’s good news, including for Europe.”
Switzerland’s Challenges and the Need for Flexibility
At the local level, Christophe Ballif notes a certain reluctance. “The climate isn’t very favorable in Switzerland right now. We’re seeing a decline in the installation of solar panels, linked to the prevailing uncertainties surrounding feed-in tariffs. But we have to keep in mind that we’re doing this to save the world, not to make a profit.”
He also points to very real technical challenges, particularly those related to the high penetration of solar power into the grid. “There is a real risk of overproduction at midday, as well as cybersecurity issues. The technical risk increases if we are unable to properly control this production.” Better coordination among grid stakeholders is therefore essential. “There are about 600 distribution system operators in Switzerland, which makes the situation quite complicated to manage.”
In his view, the future lies in a more flexible system capable of absorbing excess production. “For example, we can heat water when there is a surplus of electricity. And even for the winter demand dip, there are renewable solutions. Nuclear power remains, in any case, the worst option.”
Despite the challenges that remain, Christophe Ballif concludes on a decidedly positive note. “It’s incredible what we can now do with solar energy, and there’s still a lot more to come in the years ahead.”
Quotes taken on August 27, 2026, during the Smart Energy Event