Luminescent solar concentrators are lit AF (image: supplied).
Luminescent solar concentrators are lit AF (image: supplied).

ScienceNovember 5, 2019

How to make solar electricity cheap? Move light sideways

Luminescent solar concentrators are lit AF (image: supplied).
Luminescent solar concentrators are lit AF (image: supplied).

Vanessa Young visited Dr Nathaniel Davis’s lab to witness the concentrated capture of the sun’s energy.

In just one hour the earth receives more energy from the sun than humanity can use in a year. But capturing the sun’s energy has been famously hard – and expensive – because it is spread out of a large area. 

When physicist Dr Nathaniel Davis left the hot Aussie sun of his homeland for a PhD position in the cooler climes of Cambridge University in the UK the sun followed him into his lab. At Cambridge, he worked on a technology called solar concentrators, clever materials that trap photons and send them sideways, where they can be caught by solar panels and made into electricity. He’s now brought this solar research to New Zealand where he is exploring how this technology will make solar technology more affordable.  

In his lab, as he held up a small flat square of plastic it unexpectedly glows brightly from its edges. This is a luminescent solar concentrator. 

“This material inside absorbs light and re-emits it. It basically traps light. This one is set in plastic, but it could equally be glass. I’m figuring out how to make new materials that trap the photons and send them sideways.”

The sideways part is key. By redirecting the photons to the thin edge of the glass or plastic sheet, then the solar panels themselves only need wrap around this edge to work. So instead of needing expensive solar panels stretching across the whole flat surface, as current solar panels do across a roof, it would require only a very thin strip of them around the edges of windows, for example. 

This would mean huge savings to the cost of establishing solar energy, says Davis. 

“For a metre square panel of solar concentrator glass or plastic, the costs of the solar panels is reduced 83 fold. Stretch the glass out to three metres square – the size of a window in a commercial building – and the savings are 250 fold.”

The problem with current solar panels commonly seen on roofs is their expense. Researchers are working on bringing costs of solar panels down, but Davis’s approach is to reduce costs by using less of them through concentrating and directing the sun’s rays. It then doesn’t matter which solar panels is first in the race to be most efficient – his technology dovetails in.

“Because the concentrator works with any type of solar panel, it doesn’t matter which solar panel tech wins in future. These concentrators will just augment any solar panel technology,” says Davis, who is a MacDiarmid Institute associate investigator and Victoria University Wellington lecturer.

Dr Nathaniel Davis and his luminescent solar concentrators (image: supplied).

Solar’s base technology – they way photons push electrons around – means there’s more room for exciting developments, where other electricity generation is linked to the same idea. 

“Solar energy is the only renewable where there are real opportunities for innovation. Everything else – coal, nuclear, wind, tidal, hydro, geothermal – ends up running a turbine.  So I figured, there’s no real innovation to be found there.”

The basic idea of luminescent solar concentrators is not a new one. For nearly 50 years, chemists have been trying to perfect them – and are now getting closer to commercialising these developments.  

“The last two years, researchers have been working to solve the last few challenges, stabilising the chromophores, using non-toxic materials, working on the luminescent quantum efficiency.” 

Davis describes his work as basically recreating what nature has done. He also likes that the concentrators can be a distributed technology – everyone can have one at home rather than generation needing to be done at one central power plant. He says his research involves a combination of reducing the cost, and making solar more accessible.

With solar energy the biggest, fastest-growing renewable energy worldwide, Davis it made sense to make solar his research focus. And others are excited too; his research has attracted $1.5 million in funding this year through competitive external funding agencies such as the national science challenge and MBIE Smart Ideas. 

“These solar concentrators will be cheap, light and easy to install. The materials could even be painted onto windows or roofs, reducing costs and making solar technology more accessible.”

Which makes this all seem like a very bright idea.  

Read more about Dr Davis’ work here.

This content was created in paid partnership with the MacDiarmid Institute. Learn more about our partnerships here

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