OPVs could compete with thin-film silicon solar by 2015 says Bosch

Sara Ver-Bruggen - 05 Feb 2010

An organic solar cell technology being backed by German industrial company Bosch could start to compete with thin-film PVs by 2015.

Three years ago Bosch along with chemicals producer BASF made investments in Heliatek, a spin out from the Institute of Photo Physics [Technical University Dresden] and Ulm University, which is developing organic solar cells IP.

When Bosch invested in Heliatek OPV technology was seen as complementary to thin-film. But results concerning efficiencies and other aspects delivered by Heliatek so far indicates the technology could start competing with thin-film as early as 2015, says Dr Alexander Flaig, VP corporate research at Bosch.

Once the OPV technology's performance becomes comparable to thin-film in areas such as efficiencies and lifetimes work will start transferring to Bosch Solar Energy, the company's commercial solar energy business.

He agrees that efficiencies - how much light absorbed by the PV cell that is converted to energy - for competing with thin-film need to be 15% or thereabouts and lifetimes depend on the cost trade-off, but they will need to perform for a minimum of 10 years.

Since announcing efficiencies of 6% for its lab-made organic solar cells in mid 2009 Heliatek is working on increasing efficiencies and also on stability of the cells. To help finance its progress the company received €18 million in a second round of funding, in November 2009, under the lead of the pan-European venture capital firm Wellington Partners. Bosch, BASF Venture Capital, High-Tech-Gründerfonds and others also participated.

The fund will mainly go towards a production line in Dresden for the pilot manufacture of lightweight cells on film based on Heliatek's proprietary tandem OPV technology. A square metre of cells will weigh 0.5 kg compared with 20 kg a sq m.

 

Bosch's commercial solar business

Bosch's investment in the solar renewables industry began with its investment in Ersol Solar Energy, culminating in the acquisition of a majority shareholding, worth €500 million, in 2008.

If building-integrated organic solar cell technology is to be most efficiently exploited it will have to be developed for roof space, believes Flaig. However the market is colonised by silicon - mainly crystalline, but increasingly thin-film. Frost & Sullivan predicts that over the next 15 years thin-film PV will eventually control over 60% of the market, with OPV accounting for 18%.

Bosch Solar Energy's business includes crystalline and thin-film modules, known as micromorph. These more advanced thin-film cells achieve efficiencies of around 8%, which is 2% higher than amorphous thin-film modules. Micromorph efficiencies are expected to rise to 10% in the coming years. OPV technologies for the BIPV market will need to be at least 10%, even 15%. BASF senior VP Karl-Heinrich Hahn believes this is achievable but only with intensifive R&D efforts.

When Bosch invested in the solar power market it realised that to succeed in the BIPV market long-term, a portfolio of technologies that includes advanced but pre-competitive third generation PV technologies, such as organic solar cells.

'We evaluated different technologies and thought small molecule had a better perspective in terms of lifetimes over polymer.' The result was an investment in Heliatek.