20 Aug 2013
Concentrated PV module hits 35.9% under new test conditions, with further improvements in the pipeline.
Amonix, the Californian concentrated photovoltaics (CPV) specialist, says that it has set a new world record for solar power, after the US National Renewable Energy Laboratory (NREL) measured its module efficiency at 35.9%.
Based on recently adopted CPV IEC test conditions of 1000 W/m2 and 25 °C cell temperature, the efficiency data was generated under outdoor test conditions at NREL between late February and April this year.
The result represents the highest ever independently rated module efficiency for any PV technology – CPV is much more efficient than conventional PV systems, but requires much more expensive cell technology - and is the first time that NREL has quantified the rating for a concentrator module with the cells at 25°C rather than their normal operating temperature.
The multi-junction cells used in the high-performance module typically operate better at lower temperatures – much like laser and light-emitting diodes.
“This 35.9% IEC CSTC module efficiency is a direct comparison to [conventional] PV module efficiencies, which are often reported at IEC standard test conditions,” said Vahan Garboushian, the founder and CTO at Amonix.
The latest result builds on Amonix’s mark of 34.9% set earlier this year, while the company recently claimed that at peak operation its modules had converted more than 36% of sunlight into electricity.
Back in February, Amonix signed a co-development deal with the multi-junction cell manufacturer Solar Junction. The two companies are aiming to drive down the cost of CPV technology following a period during which conventional silicon PV modules have plummeted in price.
They believe that despite that price crash, the advantages of the CPV approach in suitably hot and sunny locations where the technology excels means that it can still be competitive – and pushing cell, module and system efficiency is a critical element of that strategy.
Garboushian adds that there is plenty of scope for further improvement, saying: “With the advent of higher efficiency cells from companies like Solar Junction, Amonix anticipates achieving considerably higher module efficiencies and breaking our currently standing world records in the very near future.”
While researchers at Sharp in Japan now hold the world record for cell conversion efficiency at 44.4%, Solar Junction’s very best cells have demonstrated 44% performance. But perhaps more important than such “hero” results, the US company believes that it is on a development path that will deliver a median cell efficiency of 42% in production.
With cell fabrication on 150 mm semiconductor substrates planned with key manufacturing partner IQE (i.e. larger wafers than are currently used), the cost of the devices should also be pushed down.
“Solar Junction’s goal is to deliver the most efficient cell into the market to help drive down the cost and increasing the CPV module power output,” reports the venture-backed cell maker.