A new way for low-cost solar power

There is enough energy from the sun landing on our world to power global energy needs a great many times over. Indeed, if we could capture a mere hundredth of the sunlight falling on to the UK and convert it easily into electricity, we could meet our current energy demands. 

 

So why don’t we do this? The reason is cost, which is still too high where conventional solar photovoltaic (solar PV) cells are concerned. Solar PV cells, which form solar arrays, are conventionally made of silicon, but the technology requires expensive manufacturing systems and cleanroom conditions to make, and this is expensive and typically requires subsidies.

 

Even so, solar PV is being increasingly installed around the world, but now there’s a new technology that seems set to eventually challenge solar PV for dominance, and greatly reduce costs into the bargain. And its name? ‘Perovskite’.

 

Perovskite is a hybrid organic-inorganic material that is relatively easily made at low cost – apparently using low temperature processes similar to those used in the printing industry. This allows the use of flexible plastic substrates.

 

Conventionally, about 85-90% of solar PV cells are based on expensive crystalline silicon, the remaining 10-15% using polycrystalline thin film cells typically made from cadmium telluride/cadmium sulphide. Such thin film cells are cheaper to make than silicon, but use rare and toxic elements.

 

Silicon solar PV cells have be as carefully designed and made as the silicon chips in PCs and smartphones but are huge in comparison, so need the highly expensive production facilities mentioned. Although – like LED lighting, which is a broadly similar technology - prices have been reducing, compared with the still widely available and affordable fossil fuels, it is difficult for silicon solar PV cells to economically compete.

 

Even so, such silicon-based solar PV cells have been surprisingly successful, with the industry growing between 40 to 70% per annum. Despite this, global energy generation from solar power is less than 0.1 % of the total energy used, so to generate a significant part of global power needs rom solar energy, a completely new technology is needed. This Perovskite. 

 

 

Materials researchers in Oxford University, led by the Photovolatic and Optoelectronic Device Group under Dr. Henry Snaith, have shown that they can make simple Perovskite solar cells using abundant and cheap materials with efficiencies nearing 20%. Other researchers in the field include Michael Gratzel and Jaques E. Moser at the Federal Polytechnic Institute in Lausanne (EPFL), Switzerland, working with the team of Roel van de Krol at Helmholtz Center Berlin-Institute for Solar Fuels.

 

This 20% efficiency could make Perovskite solar cells competitive with existing commercial silicon solar cells – especially when it is considered that they would be much cheaper to make in high volumes.

 

There’s a further, potentially highly significant benefit too, in that Perovskite solar cells can be made semi-transparent. In this way, any sunlight falling upon the cells is filtered, protecting the building interior from intense sun light while simultaneously generating electricity. 

 

In addition, Perovskite solar cells can be integrated into building facades because they are very thin and light in weight. Therefore, they have huge potential as electricity generating building materials, that could – at some stage in the future - convert that magic 1% of solar energy the UK needs, and all at a cost that could compete with dirty fossil fuels. It could at least allow for an increasing share of solar energy in the mix of renewable resources.

 

 

At Voltimum UK, we feel that our users, as well as architects, building services engineers, electrical contractors and installers generally, should all keep a close eye on developments, because if Perovskite solar cells turn out to realise their promise, there will be very significant new business to be had.