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Solar cells and panels, or modules, are central to Europe’s commitment to using renewable energy to meet up to a third of its energy needs by 2030. But while the energy will be home produced, almost none of the necessary hardware is made in Europe.
Most mass-produced cells and modules are from China, Taiwan and Malaysia, according to an EU report. The most efficient crystalline silicon solar-cell technology concepts on the market – interdigitated back-contacted (IBC) type solar cells – are produced by a small number of American and Asian firms.
Europe is now closer to having its own version of this technology. The EU-funded NEXTBASE project has developed highly efficient IBC solar cells in the silicon heterojunction configuration (IBC-SHJ).
The NEXTBASE cells can convert 25.4 % of the solar energy they capture into power.
‘This is a European record for an industrially feasible version of IBC-SHJ technology,’ says project coordinator Kaining Ding of the Forschungszentrum Jülich GmbH research organisation in Germany.
‘The current laboratory world record for a silicon solar cell is 26.7 %, which was also based on the IBC-SHJ concept but was very expensive to make. Our approach is close to the optimum level.’
NEXTBASE researchers have also developed a prototype 4-cell x 4-cell solar module that has achieved 23.2 % efficiency, which is among the highest silicon module efficiencies ever reported. Encouraged by these results, the project team has developed a cost-effective manufacturing method that could produce such modules for under EUR 0.275/watt, enabling electricity generation at costs similar to generation with standard Asian-made technologies.
‘It makes Europe competitive in solar cell manufacturing,’ says Ding.
Energy-tech innovations
Ding adds that the cells can make Europe’s energy more sustainable and secure. ‘The higher efficiency fosters the transition to renewables as it produces more energy from smaller areas than similar less-efficient cells,’ he explains, adding: ‘From an environmental and societal view, it is better to produce locally.’
The IBC-SHJ technology is key to the impressive energy conversion rate. Metallic contacts in standard mass-produced solar technology are on the front and back, wasting the solar energy that is blocked by the metal on the front. In contrast, back-contacted cells have all the connections at the back, so that they can capture solar energy across their entire front surface, in addition to being aesthetically pleasing.
Existing IBC-type modules sell only to a premium market and are expensive to make, according to Ding. The 14 industry and research partners in the NEXTBASE consortium changed designs and processes for the silicon wafers, the cells and the modules in this technology to make them both more efficient and more cost-effective.
Ding explains that IBC-SHJ cells have complicated structures. ‘There was no cost-competitive industrial way to produce them.’
NEXTBASE member Meyer Burger Research AG developed an automated process for producing the cells cheaply. ‘This process was very successful and simple,’ says Ding.
Pilot preparations
Ding believes that NEXTBASE can increase manufacturing and consumer interest in European photovoltaic technology and make IBC-SHJ modules more attractive to consumers. ‘The results are leading to commercialisation of high-efficiency PV modules based on next-generation c-Si solar cells. Without EU funding, the partners would not have worked together that closely,’ says Ding. ‘Everyone has an active interest in doing the work, even beyond the project.’
The next step will be to demonstrate that the NEXTBASE cell can work in larger modules and to industrialise production. The partners are planning a project for a pilot line, led by Meyer Burger Research AG, which now has a patent on the cell.
However, scientific information about the project’s innovations can be accessed on the NEXTBASE website, including its cost and life-cycle impact analysis, allowing other projects and businesses to develop additional next-generation solar technology in Europe.