Grace Han moved to California for a job at UC Santa Barbara and immediately noticed what Boston winters never taught her: the sun here is relentless. A chemistry professor with a practical streak, she did what any scientist would. She bought a hat, sunglasses, and started reading about DNA photochemistry. For fun.
That idle reading habit just led to something genuinely interesting.
According to BBC reporting, Han realized that DNA molecules damaged by sunburn could become the foundation for a new kind of energy storage system. The molecules twist into strained shapes when hit by UV light, and the key insight was treating them like miniature mousetrap mechanisms. Store energy in the contortion, trigger the release on demand, and you’ve got what researchers call molecular solar thermal (Most) energy storage.
The catch? Scientists have been chasing this for decades with limited success. What made Han different was borrowing a trick from evolution.
Nature’s Energy Hack
Certain plants and animals have spent millions of years perfecting how to repair sun-damaged molecules using an enzyme called photolyase. Han’s team realized these naturally-evolved molecules were perfect for her energy storage system. They’re tiny but pack an enormous amount of power relative to their weight.
In a paper published in February, Han and her colleagues demonstrated the most promising Most system yet. According to BBC reporting, the results were striking enough that Han’s students rushed to show her a video: a “very tiny kettle” in a vial boiling water rapidly from the stored energy release. When she watched the solution boil, she says it was “really remarkable.”
The numbers back up the excitement. Their system achieved 1.65 megajoules per kilogram of energy density. That’s significantly higher than lithium-ion batteries, the standard in phones and electric cars today. Kasper Moth-Poulsen, a fellow Most researcher at the Polytechnic University of Barcelona, called it “really amazing” compared to the 1 megajoule per kilogram his teams had previously managed.
This is actual progress in a field that rarely gets it.
The Problems Are Real
Here’s where the science gets honest. The wavelength of light needed to trigger the molecular shape-shifting is 300 nanometres, which is extremely harsh UV radiation. According to John Griffin at Lancaster University, while the sun does produce this wavelength, it reaches Earth “only in very small quantities.”
Then there’s the release mechanism. Han’s team used hydrochloric acid to trigger the energy release. That’s corrosive, dangerous, and requires neutralization afterward. Han herself admits it’s “not the most ideal choice.”
These aren’t small engineering tweaks. They’re fundamental limitations that would need solving before this technology could actually heat your home or office.
Why This Still Matters
The broader picture deserves attention. The world still relies on fossil fuels for most heating applications. Both Most systems and fossil fuels store chemical energy, but Most “operates without burning anything,” Moth-Poulsen emphasizes. That’s a meaningful distinction when you’re trying to decarbonize heating, which remains notoriously difficult.
Most systems could also theoretically store energy for decades, unlike thermal storage solutions that leak heat over days or months. And crucially, they could be deployed anywhere on Earth, unlike oil reserves concentrated in specific regions. Moth-Poulsen notes this advantage with a simple observation: the Strait of Hormuz blockade disrupts global fuel supply precisely because fossil fuels are geographically concentrated.
The Practicality Problem
There’s a limiting factor that less optimistic researchers aren’t shy about mentioning. Harry Hoster at the University of Duisberg-Essen points out that the light-sensitive molecules must remain relatively thin. Too thick and light can’t penetrate to all the molecules. “In a really optimistic scenario, you could probably make this 5mm thick,” he estimates.
Storing molecules in liquid form also means pumping that liquid around the system to move or release energy. More moving parts mean more potential failure points. Hoster’s logic is blunt: “The moment you need to pump stuff around you have more things that can get broken.”
Some researchers, including Han herself, are exploring solid-state versions of Most. These could theoretically become window coatings that prevent condensation or warm rooms. But Hoster remains skeptical that Most will ever provide all the heating a building needs. It might work better for temperature-sensitive satellite components or aircraft systems.
A Small Field With Big Questions
It’s worth noting how niche this research remains. John Griffin attended a Most conference last year with approximately 70 attendees. “That was basically the whole community in the world working on this stuff,” he recalled.
That shouldn’t read as a criticism. Small communities drive real innovation. But it does suggest that Most energy storage is still firmly in the “promising research” phase rather than “ready for deployment” phase. Han’s breakthrough is genuinely exciting, but several significant hurdles remain between elegant chemistry and practical heating systems.
The question isn’t whether this is good science. It clearly is. The question is whether the real-world constraints can be overcome before the energy transition moves on to other solutions.
