Plenary Speakers

Plenary Speakers
Imperial College London, England

Area 1: Solar power conversion efficiency above 40%; short and long term options

The ultimate limit for solar power conversion stands at 87% so there would appear to be plenty of scope for improving the efficiency of photovoltaic technology.  The fastest route to achieving high power conversion efficiency is by stacking multiple photovoltaic junctions. The InGaP/GaAs/Ge multi-junction solar cell represents the industry standard for space and solar concentrator applications.  However, the evolution of the technology to a 4J architectures is presently at a crossroads.  Options exist to fabricate a lattice-matched 4J cell using dilute nitride semiconductors or strain-balanced quantum wells, or alternatively lattice mismatched and wafer bonding approaches have also proven to be effective; the latter holding the present world record of 46.5%.   All these technologies are likely to achieve efficiencies in excess of 50% in the near term.   A more difficult question is the extent to which the cost of the multi-junction solar cell can be reduced.  While options exist for high throughput manufacturing, it is here that alternative approaches to high efficiency might, ultimately hold an advantage.  A perspective on the present status of intermediate band and hot carrier cell concepts will be given. 

 

Trina Solar, China

Area 2: Will we have >22%  Efficient Multi-Crystalline Silicon Solar Cells?

Multicrystalline Silicon technologies represents more than 65% of 2015 global shipments. Over the last two years, the best p-type multicrystalline silicon solar cells developed by Trina Solar have reached new efficiency records, up to 20.86% in 2014 and 21.25% in 2015. These achievements result from improvements of all aspects of the solar cell fabrication: contamination control, development of high-performance multi-crystalline silicon wafers, cell design and process optimization. Analysis show that efficiencies above 22% are possible with p-type multi-crystalline and could be reached in the next few years.

Toin University of Yokohama Graduate School of Engineering, Japan

Area 3: Organo-metal-halide Perovskite Solar Cells – Past, Present, and Future

Organo metal halide perovskites, represented by CH3NH3PbX3 (X=Br, I), are ionic crystals exhibiting multi-functions in photovoltaic power generation and optoelectronics with high extinction coefficient, 105 cm-1, for visible light. In 2008 we fabricated the first perovskite solid-state photovoltaic cell with a carbon-polymer composite hole transport material. Rapid progress in preparation of high quality perovskite crystals enabled power conversion efficiency (PCE) to reach 22%. Our group has focused on low temperature-based high throughput process and design of perovskite cells with stable hysteresis-less performance. We made plastic film-based flexible perovskite cells by using SnO2 and brookite TiO2 as electron collectors, which work with non-hysteretic PCE>13% with high mechanical stability against bending. Formamidinium-based perovskites are promising materials with good heat resistance and are capable of PCE of 20% and more. However, lead-free new materials are sought after as next direction of printable hybrid perovskite materials. My talk will present metal oxide-based lead halide perovskite cells with high stability and performance and lead-free type perovskite cells as a new direction.

REC, Singapore

Area 4: Technology Developments in REC: Silicon to Module

REC is a vertically integrated manufacturer of multi-crystalline solar panels with production facilities in Norway and Singapore. This vertical integration allows us to harmonize and industrialize the technology advancements in each division within the company. From successfully growing G5 ingots in a quad furnace using the low cost Elkem Solar Silicon (ESS),  to launching a high efficiency module combining multi-busbar, PERC and half-cut cell technology, REC has effectively utilized its entire value chain to remain competitive in the $/W race. In addition, the optimized combination of these different technologies has also resulted in improved performance in reliability and field tests. In this presentation, details of the various technical achievements within the various divisions of REC will be presented. 

Fraunhofer Institute for Solar Energy Systems ISE, Germany

Area 5: Photovoltaics Moving into the Terawatt Range

PV electricity became cost-competitive with electricity produced by oil-fired power plants, new nuclear power plants and diesel generators. Global over-production capacity for PV is coming to an end in 2016. Global PV production capacity will have to double within the next five years to 100-120 GWp/a, bringing PV installations into the Terawatt range. Therefore, a window of opportunity is opening for lucrative new investments in PV production and deployment along the whole value chain.

A key factor will be reliable technical due diligence for PV systems, to reduce investor’s risks. Moreover, rapid growth of electricity production from volatile wind and solar sources will pose new challenges for grid integration and storage technologies.

In Germany, about 35% of electricity is supplied from renewable sources, but the System Average grid Interruption Duration Index  SAIDI has been cut in half in the last 10 years, to now (2014) only 12 mins. Accommodating large amounts of fluctuating renewable energy requires to strengthen the grid, to replace manually-controlled processes by more and more automation, based on intelligent algorithms, and leave enough flexibility for unforeseen events. Any grid accommodating a high fraction of  renewables will be more resilient against fluctuations, with advantages for all users.