Converting Solar Power to Electricity on Demand – ScienceDaily

Researchers behind an energy system that captures solar energy, stores it for up to eighteen years, and releases it when and where it is needed have now taken the system one step further. Having previously demonstrated how energy can be extracted in the form of heat, they have now succeeded in making the system produce electricity, by connecting it to a thermoelectric generator. Eventually, the research – developed at Chalmers University of Technology, Sweden – could lead to self-charging electronics using stored solar power on demand.

“It’s a radically new way of producing electricity from solar energy. This means that we can use solar energy to generate electricity regardless of weather, time of day, season or geographical location. It is a closed system that can operate without causing carbon dioxide emissions,” says research director Kasper Moth-Poulsen, a professor in the Department of Chemistry and Chemical Engineering at Chalmers.

The new technology is based on the MOST solar energy system – Molecular Solar Thermal Energy Storage Systems, developed at Chalmers University of Technology. Very simply, the technology relies on a specially designed molecule that changes shape when it comes in contact with sunlight. The research has already generated great interest around the world when presented at earlier stages.

The new study, published in Physical Sciences Cell Reports and made in collaboration with researchers in Shanghai, takes the solar power system one step further, detailing how it can be combined with a compact thermoelectric generator to convert solar energy into electricity.

Ultra-thin chip converts heat into electricity

The Swedish researchers sent their specially designed molecule, charged with solar energy, to their colleagues Tao Li and Zhiyu Hu at Shanghai Jiao Tong University, where the energy was released and converted into electricity using the generator that they developed there. Essentially, the Swedish sun was sent halfway around the world and converted into electricity in China.

“The generator is an ultra-thin chip that could be embedded in electronic devices such as headphones, smartwatches and phones. So far, we have only produced small amounts of electricity, but the new results show that the concept really works. It looks very promising,” says researcher Zhihang Wang from Chalmers University of Technology.

Fossil-free, emission-free

The research has great potential for the production of renewable and emission-free energy. But there is still a long way to go in research and development before we can charge our technical gadgets or heat our homes with the solar energy stored in the system.

“In collaboration with the various research groups included in the project, we are now working to streamline the system. The amount of electricity or heat it can extract must be increased. Even if the energy system is based on simple basic materials, it must be adapted to be sufficiently profitable to produce, and therefore possible to launch more widely”, explains Kasper Moth-Poulsen.

Learn more about Most technology

Molecular Solar Thermal Energy Storage Systems, Most, is a closed energy system based on a specially designed molecule of carbon, hydrogen and nitrogen, which when hit by sunlight transforms into a rich isomer in energy – a molecule made up of the same atoms but arranged together in a different way. The isomer can then be stored in liquid form for later use when needed, such as overnight or in the winter. Researchers have refined the system to the point that it is now possible to store energy for up to 18 years. A specially designed catalyst releases the saved energy as heat while returning the molecule to its original shape, so that it can then be reused in the heating system. Now, in combination with a micrometer-thick thermoelectric generator, the energy system can also generate electricity on command.

Kasper Moth Poulsen. Researchers are active at Chalmers University of Technology in Sweden, Shanghai Jiao Tong University and Henan Polytechnic University in China, as well as the Institute of Materials Science in Barcelona and the Department Catalan for Research and Advanced Studies, ICREA, in Spain.

The research was funded by the Knut and Alice Wallenberg Foundation, the Swedish Foundation for Strategic Research, the Swedish Research Council Formas, the Swedish Energy Agency, the European Research Council (ERC) as part of of the CoG grant agreement, PHOTHERM – 101002131, the Catalan Institute of Advanced Studies (ICREA) and the European Union’s Horizon 2020 framework program under grant agreement no. 951801.

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