At any technology focused conference, especially in the PV industry, the lack of a unified technology roadmap means that picking the winners from the losers is immensely problematic.
Major technology suppliers are forced to develop their own roadmaps on what they expect will be the winning and losing technologies so that they can target R&D investment to those areas where commercial success is most likely.
This is easy when an industry has general consensus on a single or dual-path technology roadmap as this reduces R&D costs and also provides opportunities to provide better than expected products ahead of time to the overall benefit of the industry.
The PV industry is not mature enough to be at this position so duplicity in R&D and far-fetched ideas carry what many see as an extra price tag on technology migrations.
Displayed for the first time at DuPont’s booth at EU PVSEC was the material specialist's latest take or bet on the solar cell technology roadmap that it expects to place over the next five years or so.
Not surprisingly, it covers a number of cell designs and wafer choices but it certainly does not have the complete suite of c-Si cell options, compared to the full spectrum on display in conference and parallel sessions throughout the week of EU PVSEC.
The new version of the DuPont solar cell roadmap was still a “living document”, according to Peter Brenner, global marketing manager of photovoltaics for DuPont Microcircuit Materials.
Rather than simply a wish list of possible technology developments and material migrations, the DuPont roadmap represents an insight into the thinking of the mainstream PV manufacturers and the real options being considered for both incremental efficiency gains and lower cost volume cell production, and step-function changes and commercial realisation of truly next-gen volume cell technology.
Looking at conventional c-Si cell developments a lot of options remain on the table through 2020.
Improved performance coupled to lower silver paste consumption should be treated as a given for single printing processes.
Brenner told PV Tech that the next product introduction would be its Solamet PV19x series pastes, designed for lower cost considerations with improved adhesion and fine line printing capabilities, in keeping with expected customer requirements.
This would be the next step up from its Solamet PV17x paste introduced in 2012 for lightly doped emitter technology trends.
Solamet PV19x is expected to be an enhanced version of this mainstream paste, but DuPont is keeping that under wraps for another month.
However, consideration of lead-free solutions for conventional solar cells is also being developed for 2015 onwards on the back of potential EU RoHS directives on lead usage in eight years' time.
“Providing solutions ahead of time that make commercial sense is part of pulling together our five-year technology roadmap,” noted Brenner.
On the back side, PERC is at the fore, so to speak, but again different processing techniques require a wide range of solutions.
Brenner is expecting a ramp-up of PERC activities and production migration as low-cost solutions are now available and provide both incremental efficiency gains and cost reductions for multicrystalline cells over the next five years.
Migration to PERC is therefore seen as a case of incremental gains with minimal capex requirement.
However, Brenner is cautious on its PERC technology longevity, indicating later in the five-year roadmap continued efficiency gains could come with diminishing cost benefits. PERC development could therefore peak and start declining ahead of 2020.
DuPont has three mainstream next generation technologies under its 'New Architectures' sub-heading, N-type, MWT and IBC.
“These architectures will need full low-cost system solutions,” noted Brenner.
Picking a winner amongst these architectures remains problematic but N-type monocrystalline was seen as the natural long-term technology winner, given its higher potential efficiencies and significant opportunities to lower overall costs on wider industry adoption.
IBC cells should be seen as the winner in the efficiency stakes but lots of work is still required on cost-competitive and simplified volume production processes.
DuPont would seem to be putting less emphasis on heterojunction (HJ) solar cells for now but clearly the company is watching the likes of Sharp and others on how HJ technologies can be commercialised and be successful.
One key thing to watch with all the different roadmaps will be the actual lifecycle of the technologies. The mainstream sector may clearly opt for PERC and incremental steps but should a low-cost N-type technology emerge, life-cycles on P-type multi may prove to be shorter than anticipated and significantly impact the competitiveness of those manufacturers set on that course.
Having a N-type or P-type mono backup architecture ready to migrate into volume production may not be a bad idea.