Fraunhofer TechFlash: Integrated Photovoltaics

Integrated Photovoltaics : Integrated photovoltaics merges with the shell of buildings, traffic routes and vehicles. It uses land together with agriculture or covers water surfaces in flooded opencast mines. The integration of PV opens up huge potentials. Building integrated photovoltaics (BIPV) together with Agro-photovoltaics (APV) already could provide several 100 GW of solar power in Germany. Instead of conflicts of use, synergies occur, such as longer ranges for electric vehicles, local power supply for buildings or noise protection on roads and railways.

At Fraunhofer ISE, we are developing new applications in the following areas:

  • Building Integrated PV (BIPV)
  • Agro-photovoltaics (APV)
  • Vehicle Integrated PV (VIPV)
  • Road Integrated PV (RIPV)
  • Floating PV (FPV)

The concept of integrated photovoltaics opens up many opportunities;

  1. Avoidance of land-use conflicts: By integration into existing built-up areas and vehicle exteriors, dual usage of agricultural areas and floating on pit lakes, PV technology does not occupy any new valuable land areas. On the contrary, costs to provide installation area are eliminated partly or completely.
  2. Local production: Integrated photovoltaics demands many individual solutions. Products with identical dimensions and standardized design cannot be used in many cases. As a result, opportunities arise for local PV production with sustainable value creation by German and European enterprises.
  3. Reduction of material consumption: When photovoltaics is integrated into existing exterior surfaces, as in building-integrated PV or vehicle-integrated PV, the photovoltaic components are mounted onto an existing substructure. In contrast to free-standing installation on open areas, hardly any additional material is needed to mount the modules. Furthermore, the front cover of the modules, often a glass pane, also serves as a protective cover for the building or vehicle or acts as a noise barrier. These synergistic effects reduce materials consumption, improve the ecological balance of the photovoltaics and provide cost benefits which are becoming increasingly important as the prices for the solar cells themselves fall dramatically.
  4. Local power supply and mileage gain: Building-integrated PV (BIPV) and vehicle-integrated PV (VIPV) generate electricity near the consumer or on vehicles. They thus reduce usage of the electricity grid and increase the mileage of electric vehicles. Façade-integrated solar modules facing other directions than toward the equator supply more electricity in the morning or afternoon than over midday, and thus offer advantageous generation profiles.

  • Highly Efficient Technologies Particularly vehicle-integrated PV modules must generate maximum yields on a limited area. For cars, high aesthetic standards have to be met at the same time. We develop highly efficient, flexibly configurable silicon solar cells with filigree metallization and cell connection in shingles technology for appealing vehicle or building envelopes. Our Morpho coating delivers brilliant colors with low yield loss of around 7% relative. Our cell technology based on III-V-semiconductors achieves efficiencies of more than 35% and is being used primarily in the aerospace industry.
  • Customized Module Designs Many integrated applications require module designs that meet multifunctional and aesthetic requirements. We support our partners in the development of special designs and the selection of qualified materials. Highest efficiencies, curved surfaces and largely invisible module circuits can be achieved with conductively glued shingle connections. We are researching glass-free laminates in order to achieve a particularly low weight per unit area for lightweight construction applications in commercial vehicles or for low-load-bearing roofs. Thin, lightweight III-V solar cells and filmbased organic solar modules are particularly well integrated into the curved wings of electrically powered aircraft. III-V-solar cells have proven their value due to their high radiation stability in space travel. Organic solar modules enable partial transparency and spectrally selective transmission, e.g. in photovoltaically active window surfaces.
  • Characterization and Testing In our accredited calibration labs CalLab PV Cells and PV Modules we determine the precise performance data of the solar cells and modules under different operating conditions and thus create the basis for yield simulations. We test the reliability of innovative module designs based on new materials in our accredited testing laboratory and prepare the product certification. Depending on the application, integrated modules are also exposed to increased loads, for example in noise protection on roads or vehicle integration. We analyse specific loads and transfer the results into equivalent accelerated laboratory tests.
  • Precise Yield Analysis Integrated photovoltaics presents special challenges in the precise forecast of its yield potential. With physically exact models based on ray tracing and highquality weather data, we can optimize the combined land use in agrophotovoltaic applications and the performance of building integrated PV (BIPV) in partially shaded operation. Bifacial yields can be simulated as well as route-dependent yields in mobile applications. Our revenue models are validated by monitoring. Based on cost and revenue models, we offer comprehensive analyzes of cost-effectiveness and electricity generation costs.
  • Fully Automated, Flexible Production and Digital Building Processes For building integration, a variety of module variants is required, sometimes in small quantities. In a single construction project, different structures, formats, colors and designs can be used. We support our customers in the development of flexible, fully automated production lines for the cost-effective production of individual small batches. This includes data flow from planning to production (Computer-Integrated Manufacturing, CIM). Planning processes are streamlined and simplified through the digitization of Building Information Modeling (BIM).
  • System Development The integration of photovoltaics often involves adaptation and optimization of the entire electrical system. In the building envelope different orientations and shading effects have to be compensated. Vehicle integration of photovoltaic modules requires intelligent battery management systems as well as compact and robust DC converters. We develop comprehensive solutions for our customers, from system planning to software solutions and power electronic converters.

Vehicle-Integrated Photovoltaics:

Vehicle-integrated Photovoltaics (VIPV) designates the mechanical, electrical and design-technical integration of photovoltaic modules into vehicles. The PV modules blend seamlessly into the vehicle exterior and are connected to electric loads or the drive battery in electric vehicles. Simultaneously, the PV modules replace other components of the vehicle, e.g. the roof or the bonnet. VIPV increases the mileage of electrically powered vehicles and improves their CO2 balance. The aesthetic expectations on integration into the vehicle design are especially high for cars. For utility vehicles (e.g. trucks and buses), particularly lightweight PV modules are needed to avoid restricting the load capacity. Further application areas include caravans and mobile homes, delivery bicycles, trams, trains, ships, aircraft and drones.

Application options: An application example is given by electric cars which are additionally equipped with PV modules. The applied PV modules usually meet additional aesthetic requirements, e.g. special designs and curvature are possible. The additional electricity generated on the vehicle can increase the mileage by several kilometres per day. In refrigerated vans, the PV electricity can be used for electric Peltier cooling of the load. In this way, the same cooling power can be generated with less usage of the refrigeration unit and the diesel consumption can be reduced. The integration of PV modules onto the refrigerated compartment requires particularly lightweight modules which do not compromise the thermal insulation.

Agrivoltaics (Agro PV): Agrivoltaics denotes the approach of using agricultural land to simultaneously produce agricultural crops and generate PV electricity. Agrivoltaics covers a wide spectrum of intensity and type of agricultural use and the corresponding additional costs for the construction of the PV system. This spectrum ranges from the cultivation of special crops and intensive arable crops with special PV mounting systems to using land for extensive grazing with marginal adjustments on the PV side. Thereby, Agrivoltaics increases land-use efficiency and enables the expansion of PV capacity while retaining fertile arable areas for agriculture

The energy transformation requires a massive expansion of solar electricity production, combined with a high demand for space. The problem for ground-mounted systems: Arable land is a very limited and valuable resource. Agrivoltaics solves this conflict by enabling food production and electricity generation on the same area. Through dual land use, agrivoltaics not only increases land efficiency but also increases the resilience of agricultural production against global warming. Agrivoltaics provides farmers with additional income and promotes the economic development of rural areas.

Intelligent Lighting Management: To harvest solar energy and crops on the same area, a balanced ratio of light and shade is required. Fraunhofer ISE has developed models and concepts to optimize the yields from PV and photosynthesis through targeted light management. By selecting and adapting module types, mounting frames and installation parameters, it is ensured that the respective plants receive sufficient light throughout the day and year. Based on our experience with several reference plants in Germany, India and South America.

Our R&D Services:
  • PV Technology Consulting, Cost analysis - highly efficient PV technologies
  • Development of assembly and connection technology for integrated photovoltaics
  • Production of Module prototypes for integration - application-optimized cell and module designs
  • Analysis of the solar yield potential for different profiles, regions or routes
  • Module characterization and testing and service life analysis
  • Sampling in full format on industrial equipment
  • Yield simulation and monitoring
  • Development of energy and load management as well as power electronics and battery systems
  • Coordination and Management of R&D projects with industrial partners
About Fraunhofer-Gesellschaft: (Web-link)

Fraunhofer headquartered in Germany, is the world’s leading applied research organization. With its focus on developing key technologies that are vital for the future and enabling the commercial exploitation of this work by business and industry, Fraunhofer plays a central role in the innovation process. As a pioneer and catalyst for ground-breaking developments and scientific excellence, Fraunhofer helps shape society now and in the future. Its research activities are conducted by 75 Institutes and Research units across locations in Germany. The Fraunhofer employs a staff of 29,000; who are qualified scientists and engineers working with an annual outlay more than 2.8 billion Euros. Of this sum, 2.4 billion euros is generated through contract research. Our global footprint is very strong with offices and research centres in the USA, Europe and Asia. Some of our renowned innovations are the MP3 format, the white LED, the smallest of cameras. In the field of renewable, Fraunhofer holds the world record in solar cell efficiency, battery storage, and cover the entire spectrum of energy (Grid, Renewables, Storage, etc) across the value chain from materials to testing and certification. Fraunhofer has been active in India since the past several years, bringing innovative technologies and research competence to India. Fraunhofer in India is the chosen R&D and innovation technology partner of some of the major players in the field of Energy, Environment, Automotive, Electro-mobility, Materials, Production Technology and Smart Cities working with Industry, Government and Public Sector.