Australian engineers set solar efficiency world record

Dr Mark Keevers with one of the spectrum splitting, four-junction mini-modules developed at UNSW. Image by UNSW
Dr Mark Keevers with one of the spectrum splitting, four-junction mini-modules developed at UNSW. Image by UNSW

Australian engineers have edged closer to the theoretical limits of sunlight-to-electricity conversion by photovoltaic cells with a device that sets a new world efficiency record.

The solar cell configuration, developed by engineers at the University of New South Wales (UNSW) has pushed sunlight-to-electricity conversion efficiency to 34.5 per cent – establishing a new world record for unfocused sunlight and nudging closer to the theoretical limits for such a devie.

The university’s Australian Centre for Advanced Photovoltaics used a 28sq cm four-junction mini-module – embedded in a prism – that extracts the maximum energy from sunlight. It does this by splitting the incoming rays into four bands, using a hybrid four-junction receiver to squeeze even more electricity from each beam of sunlight.

Confirmed by the US National Renewable Energy Laboratory, the result is almost 44 per cent better than the previous record – made by Alta Devices of the US, which reached 24 per cent efficiency, but over a larger surface area of 800sq cm.

The result was obtained by the same UNSW team that set a world record in 2014, achieving an electricity conversion rate of more than 40 per cent by using mirrors to concentrate the light – a technique known as CPV (concentrator photovoltaics) – and then similarly splitting out various wavelengths. The new result, however, was achieved using normal sunlight with no concentrators.

UNSW senior research fellow Dr Mark Keevers said the result shows there are still advances to come in PV research to make solar cells even more efficient.

“Extracting more energy from every beam of sunlight is critical to reducing the cost of electricity generated by solar cells as it lowers the investment needed, and delivering payback faster,” he said.

ARENA CEO Ivor Frischknecht congratulated UNSW researchers, and said the achievement demonstrated the importance of supporting early stage renewable energy technologies.

“Australia already punches above its weight in solar R&D and is recognised as a world leader in solar innovation,” Mr Frischknecht said.

“These early stage foundations are increasingly making it possible for Australia to return solar dividends here at home and in export markets – and there’s no reason to believe the same results can’t be achieved with this record-breaking technology.

“It’s great to see UNSW is working with another ARENA-supported company in Victoria – RayGen Resources – to explore how the advanced receiver could be rolled out at concentrated solar PV power plants.

With the right support, Mr Frischknecht said Australia’s world-leading R&D is well placed to translate into efficiency wins for households and businesses through the ongoing roll out of rooftop solar, as well as utility-scale solar projects.

“As they become more efficient and cost effective, over time these innovative technologies will also likely take up less space on our rooftops and in our fields,” he said.

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