Could Sunburn Be the Clue? The Potential of a New Technology to "Trap Solar Energy in Molecules"

The weakness of solar power generation is surprisingly simple: it cannot generate electricity when the sun isn't shining. To use the electricity generated during the day at night, storage batteries, power grids, or other storage systems are necessary. The more we try to make renewable energy the mainstay of society, the bigger this "storage" problem becomes.

But what if solar energy could be trapped directly in molecules instead of being converted into electricity? And what if those molecules could release heat when needed, to boil water, warm a room, or manage the temperature of machinery?

Such research, which sounds like science fiction, is being conducted primarily at the University of California, Santa Barbara. Surprisingly, the inspiration came from "sunburn."

Chemist Grace Han was astonished by the intensity of the sunlight when she visited Southern California from Boston. Just a few hours outside and her skin felt irritated. This experience overlapped with her interest in the photochemical reactions of DNA. Sunburn is a phenomenon where DNA in skin cells is damaged by ultraviolet rays. The molecules that make up DNA change shape when exposed to light, becoming distorted.

This property of "changing shape when exposed to light" became a hint for energy storage.

In the field known as Molecular Solar Thermal Energy Storage, or MOST, molecules that change structure when exposed to light and stabilize in a high-energy state are utilized. When these molecules return to their original structure, the energy difference is released as heat. Imagine winding up a tiny spring with sunlight and then releasing it to extract heat when needed.

Traditional solar power converts light into electricity. In contrast, MOST stores light as chemical energy and extracts it as heat. This is different from lithium-ion batteries that store electricity. Instead of powering smartphones or EVs, this technology is suited for situations that require "heat," such as heating, hot water supply, industrial heating, condensation prevention, and temperature management.

The focus of attention is on a pyrimidone-based molecule developed by Han and her research team. Inspired by the structure of DNA, this molecule changes into a high-energy form when exposed to ultraviolet light and maintains that state. When given a specific stimulus, it returns to its original form and releases the stored energy as heat.

The research team reported that this molecule demonstrated a high energy density of 1.65 megajoules per kilogram. This is an exceptionally high value in the MOST field and is introduced as surpassing the energy density per mass of typical lithium-ion batteries. Furthermore, experiments confirmed that it could release enough heat to rapidly boil water in a small container.

The intriguing aspect of this achievement is not just the "high energy density." The potential to store solar energy for the long term and directly extract heat is significant.

When considering energy issues, many people think of electricity. Words like power plants, power grids, storage batteries, EVs, and smart grids come to mind. However, "heat" occupies a very large portion of the world's energy demand. Society requires a vast amount of heat for residential heating, hot water supply, food processing, chemical industries, drying processes, and manufacturing heating. Much of this still relies on the combustion of fossil fuels.

In other words, the challenge of decarbonization is not only about "how to generate electricity." "How to produce heat" and "how to store heat" are also major challenges.

If MOST technology is commercialized, it could be used to "charge" molecules with sunlight during the day and extract heat at night or during cloudy weather. Liquid could be exposed to sunlight on a rooftop, stored in a tank, and used for hot water or heating when needed. Alternatively, it could be used as a transparent coating on windows in cold regions to prevent condensation. There is also potential for applications in temperature management for small satellites or aircraft, and as a heat source in off-grid environments.

However, it is premature to view this technology as a "revolution that will immediately replace home heating." The original article also presents cautious views from multiple researchers.

One of the biggest challenges is the wavelength of light required to change the molecules. The current system primarily involves strong ultraviolet light around 300 nanometers. While sunlight reaching the Earth's surface does include ultraviolet rays, the amount is limited. For practical use, it needs to be improved to react more easily to natural light or operate efficiently at wavelengths closer to visible light.

Another challenge is the trigger for releasing the stored energy. Hydrochloric acid was used in the experiment. Hydrochloric acid is corrosive and requires handling and neutralization. To be widely used in homes, buildings, and industrial equipment, safer and more manageable catalysts, thermal stimuli, or combinations with solid materials are needed.

Furthermore, when used as a liquid, it requires pumping the fluid. If solar collectors, piping, tanks, heat exchangers, and catalyst reaction parts are needed, the overall system cost and risk of failure increase. Even if the performance of the molecule itself is excellent, the efficiency, price, lifespan, safety, and maintenance of the entire device are questioned in social implementation.

Additionally, if the molecules that absorb light are stacked too thickly, the light cannot reach inside. It is also important to consider how thick the liquid layer can be, how much heat can be stored over what area. To cover the heating of an entire house, a large amount of material, a wide light-receiving area, and stable circulation equipment may be necessary.

Nevertheless, this research is significant because MOST offers an alternative route to the existing idea of "converting sunlight into electricity and then storing it in batteries."

On social media, reactions to this research are mixed with expectations and critiques.

In Reddit's science and future technology communities, there are voices focusing on the significance of heat demand. The decarbonization of heating and hot water is often overlooked, but it's seen as an important area for reducing fossil fuel dependence. On the other hand, there are realistic comments like "If you're going to store heat, there are existing heat storage technologies like sand batteries," "Miniaturization makes heat escape easier," and "There's also a demand for cooling, not just heating." Thus, the reactions on social media are not just pure admiration but are more implementation-focused, asking "Where is the best place to use it?"

On LinkedIn, more specialized reactions are noticeable, especially among users close to research and the energy industry. Some posts evaluate the point that molecules can store solar energy in the form of chemical bonds and release it as heat when needed as a "promising complementary technology for long-term heat storage." However, it is also pointed out that the current stage mainly relies on ultraviolet light, the economics of scaling up are not yet visible, and it is still unknown whether it can be used for long-term storage at the power grid level.

This sentiment is quite reasonable. While the research results are groundbreaking, they are not products that will immediately change the market. Rather, they should be seen as a starting point for future material design and system engineering.

Particularly noteworthy is that researchers are also interested in directions such as "solidification" and "application to windows." The method of circulating liquid through pipes makes it easy to move heat but also poses problems like leaks, pump failures, corrosion, and maintenance. If molecules can be incorporated into solid materials or transparent coatings, simpler applications might become possible.

For example, window glass could receive sunlight during the day to put molecules in a high-energy state and slowly release heat at night or in cold conditions. Or it could be used as a thin film to prevent condensation in cold regions. Even if it doesn't warm an entire building, it could be useful for localized heat control.

In fields like satellites or aircraft, where temperature management is crucial and fuel or battery weight is a constraint, applications can also be considered. If only specific parts need to be kept at a constant temperature, materials that can release stored heat at the molecular level when needed are attractive. Practical use might progress first in small, high-value applications rather than large-scale uses like residential heating.

What makes this research interesting is that it turns a phenomenon that seems like a failure of nature into a technological hint. Sunburn is a damage humans want to avoid. DNA being damaged by ultraviolet light is a health risk in itself. However, when you look closely at the phenomenon where the shape of the molecule changes, there is a mechanism to capture the energy of light as a structural change. Here lies the idea of repurposing the photochemical reactions that life has faced over a long time into energy technology.

However, it is important not to misunderstand that this technology "utilizes sunburn." It does not use human skin or DNA for energy storage. It is merely a story of designing artificial molecules inspired by the mechanism of DNA changing structure with light.

There are three major focuses for the future.

First, how much of the solar spectrum can be utilized? If not only ultraviolet but also more abundant visible light can be used, practicality will greatly increase.

Second, the development of a safe trigger for heat release. If stable heat release can be achieved with low-temperature heat, light, solid catalysts, or electrochemical stimuli instead of difficult-to-handle chemicals like hydrochloric acid, the range of applications will expand.

Third, the total cost including materials and equipment. The cost of synthesizing molecules, degradation during repeated use, heat loss, equipment lifespan, maintenance, and environmental impact will all be compared to existing heat pumps, solar water heaters, heat storage materials, sand batteries, and storage batteries.

Looking at the history of energy technology, technologies that have shown excellent numbers in the laboratory do not necessarily change society as they are. Rather, during the process of social implementation, mundane problems appear one after another. Pipes get clogged, materials are expensive, catalysts degrade, safety standards cannot be met, maintenance is too complex—these barriers must be overcome for even the most beautiful chemical reactions to become industrial.

Nevertheless, this research has added a new option to the question of "how to store solar energy." The future is not just solar panels and lithium-ion batteries. There are situations where storing heat as heat is more efficient. In places like buildings, factories, vehicles, and space equipment that require heat rather than electricity, molecular solar thermal storage may hold unique value.

When exposed to sunlight, molecules change shape and trap energy within that shape. When needed, the molecules revert to their original form and release heat. While simple in words, its realization involves advanced organic chemistry, computational chemistry, materials science, and thermal engineering.

From the familiar yet slightly troublesome phenomenon of sunburn, a future energy storage method might emerge. Although the research is still in its early stages, viewing the sun not only as something that "generates electricity" but also as something that "stores in molecules" broadens the possibilities of renewable energy.

Whether this technology will take on home heating, become a heat source for factories, turn into a thin film for window glass, or start from niche applications like satellite temperature management is still unknown. But at the very least, the idea of not letting the sun's light end as a momentary blessing and keeping it trapped in molecules until needed is stimulating enough when considering the future of energy storage.

Source URL

BBC / AOL article "How sunburn inspired a new way to store energy"
Original article. Referencing Grace Han's inspiration, sunburn and DNA photochemistry, overview of MOST technology, research potential and challenges, and comments from external researchers.
https://www.aol.com/articles/sunburn-inspired-way-store-energy-230314720.html

UC Santa Barbara "UCSB scientists bottle the sun with liquid battery"
Announcement by the research institution. Confirmation of pyrimidone molecules, MOST, energy density over 1.6 MJ/kg, demonstration of boiling water, and potential for residential hot water and off-grid applications.
https://news.ucsb.edu/2026/022384/ucsb-scientists-bottle-sun-liquid-battery

Science "Molecular solar thermal energy storage in Dewar pyrimidone beyond 1.6 MJ/kg"
Peer-reviewed paper. Primary information on the MOST system using Dewar pyrimidone with an energy density of 1.65 MJ/kg.
https://www.science.org/doi/10.1126/science.aec6413

PubMed "Molecular solar thermal energy storage in Dewar pyrimidone beyond 1.6 megajoules per kilogram"
For confirmation of paper information, author information, and publication information.
https://pubmed.ncbi.nlm.nih.gov/41678586/

Ars Technica "A fluid can store solar energy and then release it as heat months later"
Article explaining the research content for the general public. Also confirmed as a source for reactions shared on social media.
https://arstechnica.com/science/2026/02/dna-inspired-molecule-breaks-records-for-storing-solar-heat/

Reddit / r/Futurology
Reference for social media reactions. Confirmation of comment trends regarding heat demand, comparison with sand batteries, heat loss during miniaturization, and cooling demand.
https://www.reddit.com/r/Futurology/comments/1r6zbzl/a_fluid_can_store_solar_energy_and_then_release/

LinkedIn post "Molecular Solar Thermal Energy Storage Breakthrough"
Reference for social media reactions. Confirmation of expectations for long-term heat storage, cautious views on ultraviolet dependence, and scaling-up challenges.
https://www.linkedin.com/posts/michaeljperron_a-fluid-can-store-solar-energy-and-then-release-activity-7429477323739029504-qvYE