Liquid system stores solar energy for years and releases it on demand

Liquid system stores solar ene...
An artist's concept of the MOST system charging a mobile device
An artist's concept of the MOST system charging a mobile device
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The MOlecular Solar Thermal (MOST) system can store solar power in liquid form
The MOlecular Solar Thermal (MOST) system can store solar power in liquid form
An artist's concept of the MOST system charging a mobile device
An artist's concept of the MOST system charging a mobile device

Back in 2017 we caught wind of an interesting energy system from researchers at Sweden's Chalmers University of Technology designed to store solar energy in liquid form. By hooking it up to an ultra-thin thermoelectric generator, the team has now demonstrated that it can produce electricity, a development it believes lays the groundwork for self-charging electronics that use solar power on demand.

Called the MOlecular Solar Thermal (MOST) system, the technology has been in the works for more than a decade and centers on a specially designed molecule of carbon, hydrogen and nitrogen. When it comes into contact with sunlight, the atoms within the molecule are rearranged to change its shape and turn it into an energy-rich isomer, which can be stored in liquid form.

The energy captured by the MOST system can be stored in this liquid state for up to 18 years, before a specially designed catalyst returns the molecule to its original shape and releases the energy as heat. The Chalmers team has now collaborated with scientists at China's Shanghai Jiao Tong University, who have used a compact thermoelectric generator to turn that heat into electricity.

“The generator is an ultra-thin chip that could be integrated into electronics such as headphones, smart watches and telephones," said researcher Zhihang Wang from Chalmers University of Technology. "So far, we have only generated small amounts of electricity, but the new results show that the concept really works. It looks very promising,”

The MOlecular Solar Thermal (MOST) system can store solar power in liquid form
The MOlecular Solar Thermal (MOST) system can store solar power in liquid form

The proof of concept's current output is reported to be up to 0.1 nW (power output per unit volume up to 1.3 W m−3), which might be quite small but the scientists see big potential in their MOST system, which could address the intermittent nature of solar energy by storing it for months or years at a time and allow it to be tapped into on demand.

“This is a radically new way of generating electricity from solar energy," said research leader Kasper Moth-Poulsen, Professor at the Department of Chemistry and Chemical Engineering at Chalmers. "It means that we can use solar energy to produce electricity regardless of weather, time of day, season, or geographical location. It is a closed system that can operate without causing carbon dioxide emissions.”

Having now shown that the system can be used to produce electricity, the team is focusing on improving its performance, while working toward an affordable commercial solution for charging gadgets and heating homes.

“Together with the various research groups included in the project, we are now working to streamline the system," said Kasper Moth-Poulsen. "The amount of electricity or heat it can extract needs to be increased. Even if the energy system is based on simple basic materials, it needs to be adapted to be sufficiently cost-effective to produce, and thus possible to launch more broadly."

The research was published in the journal Cell Reports Physical Science

Source: Chalmers University of Technology

I think they need to increase their efficiency by a few orders of magnitude for anything but the tiniest sensor applications. Even a milliwatt would take a liter of conversion cell.
fluke meter
It would be good to know some kind of current efficiency and a guess of what the efficiency could get to. How does this compare to say fuel cell and making H with solar and then making electricity with H from fuel cell..
Paul Anderson
What would be the application that requires storing energy for months or years at a time? Spacecraft maybe, but even there the current nuclear thermal generators produce energy for months or years at a time.
The fact that they're using an 'ultra-thin thermoelectric generator', which basically means very low efficiency, implies that this is not going to have wide-spread application. They're also not mentioning the temperature generated, which determines the maximum possible efficiency. If it's just producing slight warming, then as paul314 said, it'll be several orders of magnitude below what's needed for a useful energy storage system.
Lamar Havard
Interesting...but the renewable I'm most interested in is 'rain power'. Collectors made of aluminum foil, PTFE (Teflon tape) gaffer's tape and aluminum duct tape. When the rain, which has a + charge runs over the aluminum contact, it releases the charge and it is collected and stored. The guy in the YT video (Rain Fuel) said enough collectors to cover a square meter can put out 50W. A square meter solar panel puts out around 150W. Solar panels for sunshine, rain panels for LIQUID sunshine!
Even without thermionic electrical power generation, the material would serve a very useful purpose as a source of heating during winter and thereby reducing the need for carbon based heating systems. As a person who lives off grid, that was the first thing I saw
Patricia Mitchell
I installed a 7.6ktl solar system on my roof. How do I take advantage of this kind of energy storage?
White Rabbit
Folks, it's a "proof of concept"!! It's not (yet) a product. It was an interesting idea, so they tested the idea, and it was proven. All of these blindingly obvious observations of possible deficiencies are exactly what will be addressed in the next years/decades of development - not to mention hundreds more that those of us not involved in the project can't possibly predict. Why is there such a rush to share the embarrassment of those that told the Wrights "it'll never fly"?