Solar energy is a renewable energy source that provides numerous benefits to everyday life. These benefits include helping to grow the food we eat, influencing our weather patterns and allowing us to generate clean and renewable electricity with the help of solar panels. Whilst many advantages apply, the process of using solar energy to generate electricity also has its drawbacks, one of which is storage of solar energy. In countries such as the UK, the unreliable and cool climate means that solar energy is also unreliable as a source of energy. Cloudy skies reduce its effectiveness. So, an urgent need has been felt to find ways to store and transfer solar energy.

It seems Swedish researchers have found a wonderful way to solve this problem. Researchers at Chalmers University of Technology in Sweden have discovered a way to store solar energy in chemical form, transport it to where it is needed, then release it as heat with an efficiency of up to 80%.

The researchers say the discovery has the potential to solve a number of problems with solar energy, including storing and moving the energy so that it can be released at the right time and place.

Professor Kasper Moth Poulsen, who is leading the research, said: 'The dream is to create a universal solar battery that releases heat on demand'.

According to the team's paper, published recently , the system has the potential to release heat at up to 238⁰C.

Although it is not yet cheap enough to compete with conventional space heating, it would already have specialist applications. The paper gives the example of providing heat in remote locations or harsh environments that are without access to full-time power, and where 'the cost of delivering fuel enhances the competitiveness of renewable approaches'.

The technique is based on an organic compound called norbornadiene that alters double-bonds to single-bonds on exposure to sunlight, becoming a quadricyclane. To release the energy, a catalyst is added and the process is reversed.

This enhances the efficiency of non-photovoltaic solar receptors, which are able to make use of the full spectrum of sunlight. By contrast, a PV module has a maximum conversion rate of only 20%. 

The research was initiated at Chalmers University more than six years ago. At the time, the solar energy conversion efficiency was 0.01% and the expensive element ruthenium played a role in the compound.

Researchers saw an opportunity to develop molecules that make the process much more efficient. They are demonstrating a robust system that can sustain more than 140 energy storage and release cycles with negligible degradation.

Further research into the system will be based on making the chemical constituents cheaper and the catalyst less toxic. Making the liquid safer would allow the system to be used for applications such as portable cooking devices that can be 'charged' with sunlight and used to cook after the sun has gone down.

The paper comments that 'breaking through the barrier for commercialisation in a very competitive solar landscape would be a significant and difficult challenge, but breakthroughs are likely, given the relative youth of solar technologies and the current worldwide trend to phase out fossil fuels'.

The paper can be read here and a YouTube video explaining the research can be viewed here.

Sources:

http://www.globalconstructionreview.com/innovation/swedish-researchers-find-w7ay-liqu7idise-so7lar/

Renewable Energy world

'Energy & Environmental Science' Journal