mirrors arc
A new technology has recorded 40% solar efficiency in photovoltaics used as receivers in CSPV units like above that use sun-tracking heliostats to concentrate solar power collection. Getty

A record efficiency of conversion of sunlight into power has been achieved by researchers at the University of New South Wales who reported figures above 40%, beating previous records of 36.7%.

"The new results are based on the use of focused sunlight, and are particularly relevant to photovoltaic power towers being developed in Australia," UNSW Scientia Professor and Director of the Australian Centre for Advanced Photovoltaics (ACAP) Martin Green said in a press release.

It was independently confirmed by the National Renewable Energy Laboratory (NREL) at an outdoor test facility in the United States.

However, Green is hopeful it can eventually be used in housetop panels which currently have efficiencies below 20%.

While traditional methods use one solar cell, thus limiting conversion efficiencies to about 33%, the new technology splits the sunlight into four different cells, which boosts the conversion levels, Green told AFP.

The new design uses an optical bandpass filter to capture sunlight that is normally wasted by commercial solar cells and convert it into electricity at a higher efficiency than the solar cells themselves ever could.

Australian company RayGen which provided design and technical support for the high efficiency prototype said the company was capable of achieving "close to 45% system efficiency in the next few years".

Power towers that use such panels are being developed by RayGen Resources.

The concentrated solar photovoltaic technology uses an ultra efficient concentrated photovoltaic receiver combined with an optimised heliostat collector field of sun-tracking mirrors.

In this system, the heliostats concentrate sunlight onto the photovoltaic cells in the central receiver on the tower. By using large arrays of inexpensive mirrors, the CSPV technology cuts on cost, according to Greentech Media.

CPV has a 0.25% global market share of the 40 gigawatts of PV being installed in 2014.

Among the CPV benefits listed are its low water requirements and environmental impact, but there are challenges in land required and maintenance of the mirrors.

The study paper will be published soon by the Progress in Photovoltaics journal.

Solar cell manufacturers face a trade-off between performance and cost. Most commercial solar cells are made of crystalline silicon that take a lot of energy to produce but give efficiencies of 20% and above. Thin-film solar cells have lower material costs, but are half as efficient.