Breakthrough at UNSW could make solar panels cheaper, more efficient

A research team at the University of New South Wales’ ARC Photovoltaics Center of Excellence, led by Professor Stuart Wenham, has made a major breakthrough in silicon solar photovoltaic (PV) cell technology which could both reduce the cost of having a solar system installed as well as increase power yield in systems. Professor Wenham was recently interviewed about the work in the Sydney Morning Herald.

Solar cells are the most expensive part of a solar panel–accounting for over half the cost–and silicon is the most commonly-used material in solar cells across the globe. Silicon solar cells are produced in 3 different forms–monocrystalline, polycrystalline, and amorphous.

Currently, solar panels using the former 2 technologies dominate the rooftop solar PV market. Whilst generally having a higher conversion efficiency (sunlight–>energy), they are also more expensive to produce. On the other hand, lower-grade amorphous (literally, ‘shapeless’) silicon, which has not gained as much traction in the rooftop solar market as the others, tends to be less efficient but also less costly.

The UNSW research team’s discovery promises to change the game for amorphous silicon and further boost efficiency in the other technologies. Their breakthrough has to do with the process by which silicon is purified in preparation for use in solar panels. Hydrogen atoms are used in the process to remove defects in silicon, enabling cells to convert more light into usable power. The team has found a way to better way to control and utilise hydrogen in this manner.

Some of the more efficient, commercially available solar panels using monocrystalline and polycrystalline silicon have efficiencies in the range of 17-18% these days; typically about 5-7 percentage points higher than amorphous silicon panels. The most efficient panels using mono/poly silicon cells have conversion efficiencies in the low 20s. Using the technique that Prof Wenham’s team has developed, even the less efficient amorphous silicon solar panels would rival or exceed current efficiencies–at a much lower cost.

As it has not yet been implemented on a large scale–it will be about 3 years before it is commercialised–this new technique has yet to have an impact on solar system installation prices. Even still, prices have fallen dramatically over the past few years, due in great part to hugely increased production in China coupled with increased competition between solar panel manufacturers internationally, as well as amongst solar panel installers domestically. Although it has resulted in multiple bankruptcies as well, this competition has made solar PV more accessible than ever for homes and businesses in Australia and around the world.

Solar system prices are expected to gradually continue falling into the future as breakthroughs like this happen and are incorporated into production processes. In Australia, however, solar PV already offers an increasingly attractive value proposition because of falling system installation costs and the rising price of electricity. Looking for savings on their electricity bills, many homes and businesses are making the switch to solar even in states where no feed-in tariff incentive is offered.

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