• Question: What are the biggest limitations of harnessing solar energy , compared to the conventional heating methods

    Asked by anon-255461 to Bryony on 21 May 2020.
    • Photo: Bryony Hockin

      Bryony Hockin answered on 21 May 2020:

      An excellent question! If we’re talking about solar energy in general (e.g. to replace fossil fuels) the biggest problems are cost and space. Solar panels need a lot of space, they’re weather-dependent (they don’t work as well on cloudy days), and they’re expensive to make because they’re a new technology. Another challenge is that lots of solar cells are based on silicon, which is quite rare, so a lot of research is going on into other materials that can replace silicon. I don’t use solar cells in my work (although a lot of my coworkers do), instead I’m working on solution-based photo-catalysis. What this means is that I design molecules, called catalysts, that help to lower the energy barrier of a reaction and run the reaction faster or more efficiently. My biggest challenge at the moment is designing these catalyst molecules so that they absorb solar energy as efficiently as possible, and they can safely be applied on a larger scale for useful chemical reactions such as making drug molecules.

Comments

  • Photo: Kat

    Kat commented on :

    In addition to Bryony’s great answer:

    Cost is a massive barrier – As I understand it, 90% of the worlds solar cells are made from silicon – which is quite a lot when its a rare resource!

    Efficiency – the conversion of the solar energy into electrical energy via solar cells is not very efficient (I think it’s only about 20% for commercial solar cells) so that means you 80% of the solar energy is wasted. Lots of research like Bryony’s is going on around increasing the efficiency, reducing cost and using non-toxic & sustainable materials for these.

  • Photo: Radha

    Radha commented on :

    I would like to add a comment to both the excellent answers from Bryony and Kat. The context of the answers provided here relates to solar photovoltaics (generation of electricity). The efficiency of solar photovoltaic is the amount of electricity generated in comparison to the sun light (photons) shining on the solar cell. At present, there can be close to 30% conversion of light to electricity using recently discovered perovskites combination with conventional silicon. Solar thermal (conversion of solar energy to heat water/air) is about 90% efficient but cannot generate electricity.