A brighter world, one story at a time.

In 2018, a Swedish research group from Chalmers University of Technology made a giant breakthrough in solar storage technology. The team developed a chemical able to store solar energy for an extended period of time (up to 18 years). The new technology makes solar much more practical in terms of suppling the uneven demand generated by large populations.

  • Solar thermal energy can be stored for example as thermal energy in rocks or hot water, in phase change materials, or in thermochemical energy storage materials. A particular challenge is to identify compact thermal storage solutions capable of operating in the medium temperature range (100–180 Celcius) (1)
  • In this context, one possible solution is to use molecular photoswitches where the solar energy is stored in high energy photoisomers. This way of storing solar energy has been referred to as molecular solar thermal (MOST) (1)

The journal article goes on to say the MOST mechanism works by utilizing a parent molecule, which when irradiated photoisomerizes to a high energy variant; the new isomer can then release the energy on demand by applying heat or introduction of a catalyst.

This new technology allows for one of the biggest drawbacks to be addressed, which is, according to critics of solar energy, the inconsistency and store-ability of solar. This is a problem because while the sun is up during the day, most of the time peak demand occurs after the sun has set; this offset in production vs. usage is one of the biggest reasons wider adoption of solar has stagnated.

The researchers have continued to develop this technology, and, more recently, they developed another integral piece of the puzzle.

The team at Chalmers succeeded in creating a chip that transforms the energy-rich chemical to usable electricity in a plethora of different applications from consumer gadgets to more industrial applications.

  • After previously demonstrating how the energy can be extracted as heat, they have now succeeded in getting the system to 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 energy on demand. (2)

While this technology might not be ready for market quite yet, it is still very inspiring to see that people are continually making progress towards making the world a better place and striving towards a more sustainable and green future.

Written by the Happy Daze Team


1: Liquid Norbornadiene Photoswitches for Solar Energy Storage in the journal Advanced Energy Materials.

2: Converting solar energy to electricity on demand Chalmers University of Technology

3.  Molecular Solar Thermal Energy Storage in photoswitch oligomers increases energy densities and storage times in the journal Nature Communications.

4. Norbornadiene-based photoswitches with exceptional combination of solar spectrum match and long-term energy storage in Chemistry: A European Journal.

5. Macroscopic Heat Release in a Molecular Solar Thermal Energy Storage System in the journal Energy and Environmental Science.

6. Emissions-free energy system saves heat from the summer sun for winter Chalmers University of Technology

  • The research has been 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) under grant agreement CoG, PHOTHERM - 101002131, the Catalan Institute of Advanced Studies (ICREA), and the European Union's Horizon 2020 Framework Programme under grant agreement no. 951801
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