Monday, 23 March 2015

A Moment of Clarity for Solar Power

There's something about solar energy that I just find fascinating. Maybe it's the because it could be our saviour and the key to practically endless free energy, or it could be that it's the mission to mimic one of life's most complex and fundamental biological processes (photosynthesis). Whatever it is, it's got me hooked! 

That said, I am no physicist and I do not pretend to be one! What I am, though, is someone who is very interested in watching the technical advances in solar technology and who takes pleasure in telling the story of solar energy. 

This article sparked from a conversation with one of my housemates about solar energy. We talked about how solar energy could power california 5 times over without using up any additional space and then went onto the possibility of "paint-on solar power". Then we got to talking about how cool it would be if we could have transparent solar cells, so you could replace your windows with "solar windows" instead of needing to install cumbersome solar panels to your roof. 

After doing a little digging, I found that this could actually happen and that people have made them already! These transparent solar cells work as a solar concentrator and make use of the abundant near infrared spectrum of light, which we humans cannot see. The near infrared light is then concentrated and directed onto thin, high performance photovoltaic solar cells at the panel edge.

Unsurprisingly this work made it onto the front cover of the journal Advanced Optical Materials!

Because the solar concentrator does not absorb any light that we can see, it is completely transparent to the human eye. It takes advantage of the fact that near infrared light makes up a large proportion of the amount of light wavelengths that reach the Earth from the Sun (~52%). It is also my understanding that photovoltaic cells work well at converting this form of light into electricity, however the intensity of light at these wavelengths is not as high at certain wavelengths, a large portion of it is comparable to visible and UV light intensity, so it's a good candidate for using in the creation of transparent solar cells. 

near-infrared makes up the majority of solar energy distribution. Something that we could take advantage of.  

The current form of these cells work at ~0.4% efficiency, but could be improved to about 10%. This isn't quite as good as some solar panels, but they could be scaled and commercialised to be much cheaper and if you had a whole skyscraper made with these panels as windows, you would get a lot more solar power than just covering the top of the same skyscraper with 20% efficient panels. 

These could be great for replacing windows, but they could also be used for our smaller electronics too. If you had a smartphone or laptop with this technology, you could at least greatly increase the battery life of mobile devices and maybe one day we could be rid of charging all together. This might be a long time off, but if it comes through it could be a real game changer.  

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PS: Thank you to Reddit users Nightcaste and balkibartakomous for pointing out that these panels could also have huge potential in the automotive industry, particularly for passive parking purposes! 


  1. I totally agree with you! Utilizing the power of solar energy could be the solution we've all been waiting for. Of course, it's sad how the world isn't ready for something so great yet. I mean, it's been innovated, but somehow, only a fourth of the world has been making use of it. Anyway, I enjoyed the read, Sam. I'm glad I stumbled upon your blog. Thanks for sharing and all the best! :)

    Rachael Massey @ Auto Controls

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