Solar Energy
Photothermal energy, one of the lesser-known branches of solar energy, is becoming increasingly important in the debate about the future of energy. While public attention has focused on photovoltaic solar panels, this technology based on the use of solar heat is beginning to consolidate itself as a complementary alternative with a strategic role: to provide stability and storage capacity to the electricity system.
In a context of transition towards emission-free energy models, experts in the energy sector highlight that not all renewables fulfil the same function. Photothermal energy, in particular, is emerging as a technology capable of meeting one of the great current challenges: the intermittency of solar and wind production.
From the sun to heat: a technology with a different approach
Unlike photovoltaics, which directly convert sunlight into electricity, photothermal energy is based on a different principle: concentrating solar radiation to generate heat at high temperatures.
This heat can be used in a variety of ways, although its best known application is the generation of electricity through thermal cycles similar to those of conventional power plants. However, its scope goes beyond the electricity sector, as it can also be used in industrial processes or in the production of drinking water through desalination.
This multifunctional nature is one of the factors that explain the growing interest in this technology in regions with high solar radiation.
The differential value: storing energy in the form of heat
One of the elements that specialists highlight the most is the storage capacity of photothermal energy. Unlike other renewable sources, this technology allows energy to be conserved in the form of heat for several hours, and even days, using materials such as molten salts.
This thermal storage makes it possible to adjust electricity production to demand, something that is especially relevant in electricity systems that are increasingly dependent on variable sources such as solar or wind.
In practice, this means that a photothermal plant can continue to generate electricity even when the Sun has already set, reducing reliance on other backup technologies.
A complementary role in the energy mix
The current energy debate is not only about which technologies are more efficient, but also about how they can be combined to ensure a stable supply.
In this scenario, photothermal energy does not compete directly with photovoltaic or wind energy, but acts as a complement. While photovoltaic solar energy stands out for its low cost and quick installation, photothermal energy provides an advantage that is difficult to replicate: the ability to manage energy over time.
This balance between cheap production and operational stability is one of the aspects that is arousing the most interest among electricity system operators and regulatory bodies.
Where this technology is growing
The implementation of photothermal energy is not homogeneous at a global level. Its development is mainly concentrated in regions with high levels of direct solar radiation, where its performance is more competitive.
These areas include southern Europe, North Africa, the Middle East and some areas of America and Australia. In these territories, the climatic conditions favor the use of the solar resource without prolonged interruptions due to cloudiness.
Spain, in particular, has been one of the pioneering countries in the development of solar thermal plants, becoming an international benchmark in this type of technology.
Economic challenges and technological competition
Despite its advantages, photothermal energy faces significant challenges. The main one is economic. The initial investment required to build this type of facility is still high compared to other renewables.
Added to this is the technical complexity of the systems, which require specific infrastructures for the capture, transport and storage of heat. In addition, the maintenance of these systems is more demanding than in other more widespread technologies.
Another key factor is the strong competition from photovoltaic energy, whose costs have fallen significantly in the last decade, accelerating its large-scale deployment.
These elements have limited the expansion of photothermal energy, although they have not slowed down its development in strategic projects.
Innovation and new opportunities
Despite the challenges, the sector continues to evolve. In recent years, different lines of research are trying to improve the efficiency and reduce the costs of photothermal energy.
Among the main innovations are the development of new materials for thermal storage, the improvement of thermodynamic cycles and the integration of hybrid systems that combine photovoltaic and thermal energy in the same installation.
There is also growing interest in its application in industry, where solar heat can replace fossil fuels in high-temperature processes, an area that is difficult to electrify with other technologies.
A technology with strategic potential
Although its presence in the public debate is less than that of other renewables, photothermal energy is considered by many experts to be a strategic piece in the future of the energy system.
Its ability to store energy and produce electricity in a manageable way makes it a useful tool for moving towards more stable electricity grids that are less dependent on fossil fuels.
In a scenario of increasing electrification and expansion of renewables, photothermal could play a key complementary role, especially in combination with other clean sources.
Conclusion
Photothermal energy is not a mass technology, but it is a solution with increasing strategic value. Its ability to transform solar radiation into stored heat and then into electricity places it in a unique position within the range of renewable energies.
As electricity systems evolve towards more complex and decentralised models, technologies such as photothermal could gain prominence not because of their volume, but because of their ability to bring stability and flexibility to the energy system as a whole.