IEA PVPS Survey Explores Vehicle Integrated Photovoltaics

• IEA PVPS' latest survey explores the preferences and expectations for faster adoption of VIPV 
• Respondents see silicon PV technology as the most preferred technical solution now, but tandems expected to replace in 2030 
• The biggest technical and market bottlenecks identified as a complex manufacturing system and combining PV with vehicle safety standards 

A team of 110 experts in the field of vehicle-integrated photovoltaics (VIPV), surveyed by the International Energy Agency Photovoltaic Power Systems Programme (IEA PVPS), see significant potential in the field, but cite complexity of manufacturing as the biggest technical bottleneck. 

As per the recent survey conducted by the IEA PVPS under its Task 17's State-of-the-Art and Expected Benefits of PV-Powered Vehicles, respondents believe the most important benefit of VIPV is the reduced need for charging. 

The most important system properties are efficiency, km/year and range extension for VIPV systems. Color is the least important on the priority list. 

"The survey outlines specific cost targets for VIPV systems, aiming for a reduction in manufacturing and installation costs by 2030 by as much as 60%. This will require not only economies of scale for production but also the development of new production technologies and innovations," reads the survey. 

Experts see potential for manufacturing costs for VIPV to drop to less than $1/W by 2030, from the current level that ranges between $2/W and $5/W. However, a complex manufacturing system and combining PV with vehicle safety standards are the biggest technical and market bottlenecks to get there, according to the respondents. 

Appearance and reliability follow next on the list of the bottlenecks. These VIPV experts are not as concerned about supply chain problems, yield prediction and dynamic shading losses. 

In terms of solar cell technologies, the preference of the majority as the most appropriate PV technology today is crystalline silicon, but it should change to perovskites and tandem by 2030. 

As experts in the VIPV space, they prefer to not see any visible metal on the PV modules used; hence, it is the interdigitated back contact (IBC) metallization technology that stands out as the preferred technology. Back contact foil-based technology emerged as the most preferred cell interconnection design of choice, followed by back contact-stringing, and multiwire, among others. 

"The interconnection technology has implications for the visual appearance but also for the flexibility of design and cell layout. The preferred technology was back contact in both cases," observed the analysts. 

The survey also touched upon the choice of PV cover material for it has implications for weight, safety and reliability, and visual appearance for various vehicle elements. For solar technology integration on the roof of the vehicle, it is glass that's preferred, but for the doors, hood and the boot, polymer took a majority of votes. Polymer is considered to make it easier to build curved modules. IEA PVPS believes this indicates a strong aesthetic consideration in VIPV design. 

In terms of color, respondents were split between deep blue and black colors for VIPV vehicles. In order to have more color choices for a VIPV vehicle, the analysts believe a module with 20% efficiency will be reduced to 15%. However, the survey writers cite an Australian study to claim that people are prepared to pay close to $1,800 to have the PV color match the color of the vehicle, that points to a niche market segment. 

The survey writers sum up, "Looking ahead, the expansion of the survey beyond researchers in PV and automotive research to include more industry professionals is recommended for a comprehensive understanding of VIPV preferences and requirements. Overall, these survey findings serve as a valuable foundation for the future development and integration of VIPV systems, aligning with evolving technological trends and user expectations." 

The complete IEA PVPS survey titled Expert Survey on Technical Requirements of PV-Powered Passenger Vehicles 2024, is available for free download on its website.