Expert Talk: Here comes the sun: A positive tipping point for solar energy

2024: A year of unwanted climatic records

2024 has been a year of broken records, but not the kind we can celebrate. It was officially the hottest year ever recorded, with almost every month setting a new temperature record [1, 2, 3]. And when a month didn’t reach first place, it came in a close second right after 2023. Global temperatures have now risen by 1.5°C compared to pre-industrial levels (1850), a threshold scientists have long warned could trigger severe and irreversible climate impacts [1, 2, 3]. This increasing heat is not just a statistic; it is already triggering dangerous climate negative tipping points [4, 5]. Tipping points are critical thresholds, and once they’re crossed, they set off self-reinforcing, irreversible changes. One alarming example is the melting of Greenland’s ice caps. As the ice disappears, less solar radiation is reflected back into space, causing even more surface heating [6]. Additionally, these ice caps contain permafrost, which stores large amounts of methane, a potent greenhouse gas (GHG) that, once released, accelerates climate change even further [7, 8, 6]. Speaking about GHG, another record was achieved in 2024 in human-caused carbon dioxide (CO2) emissions [3, 2].
As a result, actions need to be undertaken to slow down global warming. Therefore, international efforts such as the Paris Agreement aim to limit temperature rise to 1.5°C by 2030 [9]. Furthermore, the European Green Deal has set an even more ambitious target: achieving net-zero emissions by 2050 [10].

Solar energy as an important driver for the energy transition

As energy demand rises due to the behavior of a growing population and industrialization, a shift from fossil fuels to clean energy is critical to meet the global climate goals. A key solution is electrification, which includes transitioning the powering of homes, heating, and transport from fossil fuels to electricity [11, 12]. Technologies like electric vehicles (EVs) and heat pumps are far more efficient than their fossil-fueled counterparts, reducing emissions while improving energy use [11]. Although this transition is expected to double or even triple electricity consumption, the superior energy efficiency of electrified systems will ultimately lead to a reduction in overall energy demand [12, 13].

The solution for this significant growth in electricity demand while minimizing the emission of GHGs is the deployment of renewable energy sources, as they are highly scalable and thus can rapidly be expanded to meet the growing needs. Among all sources, solar power plays a leading role as the sun is the most abundant energy source on Earth. Furthermore, in the past few decades, solar energy capacity has doubled every three years, illustrating a significant exponential trend [14]. With its rapid growth and scalability, solar energy is a key driver of the clean energy transition and essential for a sustainable future.

From niche to necessity: Solar energy reaches its breakthrough moment

The transition to renewable energy is not a question of if but how fast it can happen. Fortunately, solar and wind energy follow a fascinating, non-linear trend known as learning rates [15]. This means that every time the cumulative installed capacity doubles, the cost of the technology drops significantly. For wind energy, this learning rate is about 10%, while solar photovoltaic (PV) technology benefits from an even steeper rate of 20% [15]. As a result, the more we install, the cheaper these technologies become, which results in a self-reinforcing cycle that has already triggered a positive tipping point. This tipping point means that solar and wind energy are now on an unstoppable path to dominate the global energy mix [15]. These prospects are clearly illustrated in Figure 2 [15].
Both solar and wind energy are in the majority of the world already cheaper than their fossil fuel counterparts, and thanks to their learning rates, this cost gap will only continue to grow [15, 16]. At present, they are the most affordable energy sources available. Moreover, with solar energy’s higher learning rate compared to wind, it is set to outpace wind power in the future. This trend is clearly illustrated in Figure 2, where solar PV emerges as the dominant energy source in the coming years. Additionally, global investments in solar energy continue to rise and have already surpassed those in all other energy generation sources combined [17].

It is to be noted that while solar PV has a lower energy density than fossil fuels, a substantial portion of energy is lost in fossil fuel-based systems, whereas solar PV and electrification offer significantly higher efficiency. Moreover, the true strength of solar PV lies in its scalability, enabling widespread deployment across diverse applications. Whether on rooftops, vast solar farms, or integrated into urban infrastructure, solar energy is adaptable to different environments, helping to power a more resilient and sustainable future. Currently, 86% of the world’s population depends on imported fossil fuels, making them vulnerable to geopolitical instability [11]. As solar energy takes a larger share of the energy mix in the future, it will enhance global energy security, reducing reliance on imports and providing a more stable and sustainable energy future.
Nevertheless, the problem of the past was the high cost of renewable energy, whereas the current problem lies in the intermittent behavior of the renewables, which results in grid resilience [15]. Hence, energy storage is crucial in the energy transition, and batteries offer a key solution. While they are still expensive, their costs are rapidly decreasing thanks as they also exhibit high learning rates [15, 11]. The non-linear behavior of these technologies (i.e., wind energy, solar energy, and battery storage) is clearly visualized in Figure 3 [11].
Nijsse et al. provide a comprehensive analysis of learning curves and the positive tipping point in photovoltaic technology in their Nature Communications publication, “The Momentum of the Solar Energy Transition” [15].

EnergyVille in Belgium is already conducting groundbreaking research to drive the energy transition forward. In 2024, five new projects have been approved, each tackling a key challenge in the shift to sustainable energy [18]. Here, they aim to improve battery technology usage by using artificial intelligence and explore how Belgium’s economy can transition to climate-neutral energy [18]. Furthermore, studies will be conducted to make offshore grid investments more efficient, unlock industrial flexibility to support the grid and combine offshore wind farms with floating solar panels to maximize renewable energy production [18].
Next to these projects, EnergyVille is also advancing research in PV technology, with a strong focus on improving the efficiency and stability of next-generation thin-film solar panels. Recently, they were among the first to deliver real-world data from a long-term outdoor stability test of perovskite mini-modules, marking an important step toward making this promising solar technology more reliable and market-ready [19]. Furthermore, EnergyVille conducts pioneering research on building-integrated photovoltaics (BIPV), where multiple PV devices are installed and monitored on fa¸cades to enhance the performance, reliability, and feasibility of BIPV applications [20].

The best in class: China’s dominance in renewable energy

China has a dominant role in the installation of renewable energy, where it is responsible for 60%, as shown in Figure 4. It is the frontrunner in both energy transition and electrification, with the highest share of newly sold electrical vehicles in 2024 [21].
China’s leadership in renewable energy is not only transforming its own energy system but also influencing global markets. As a result of crossing the tipping point and the high learning rate of solar PV, significant price reductions will continue to follow. These falling costs will have a major impact worldwide, especially in lower-income countries where governments have limited financial resources [15]. As solar PV reaches cost parity with the cheapest fossil fuel alternatives in these regions, large-scale deployment will accelerate even further [15]. As the tipping point for solar energy results in an irreversible, self-reinforced effect of price declines for solar installations, external political factors such as the current U.S. regulations will have a limited impact on the overall trajectory of the global energy transition [22, 16]. The momentum behind renewable energy will not automatically be reversible.

Key takeaway message

• 2024 was the hottest year on record, pushing global temperatures past the critical 1.5°C threshold and triggering irreversible climate negative tipping points.
• Electrification and the rapid expansion of solar energy are key to reducing emissions and meeting the world’s growing energy demand sustainably.
• Solar and wind energy have reached a positive tipping point, where increasing deployment drives down costs, making them the dominant and most affordable energy sources.
• While renewable energy solves the issue of high energy costs, their intermittent nature requires advances in energy storage, which is also rapidly improving due to high learning rates.
• China’s leadership in renewable energy is driving global solar expansion, lowering costs, and accelerating the energy transition worldwide, especially in lower-income countries.

References

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