Fraunhofer Institute for Solar Energy Systems ISE

Tandem Photovoltaics –
The Road to Higher Conversion Efficiencies

Our research aim is to increase the energy conversion efficiency of photovoltaics and bring down the costs. Tandem photovoltaics holds great promise for achieving these goals and is among the fastest-developing solar technologies today.

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Heat Pumps –
A Key Technology for the Energy Transition

Heat pumps will be the dominant heating technology in the future energy system. Scientific studies have shown they will play a key role in reducing greenhouse gas emissions in the building sector. Today heat pumps are used in numerous types of buildings.

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Integrated Photovoltaics – Areas for the Energy Transformation

Integrating PV technology into building envelopes, vehicles and roads, as well as over agricultural fields and floating on water surfaces, capitalizes on surface areas with a tremendous potential for generating solar power.

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© Fraunhofer ISE/Foto: Dirk Mahler


Photovoltaics is a central pillar of the future energy supply from both an economical and ecological point of view.

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Energieeffiziente Gebäude
© ingenhoven architects H. G. Esch

Energy Efficient Buildings

Energy efficiency in buildings plays a central role in climate protection. Currently the building sector in Germany is responsible for over 40% of the final energy demand.

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© Fraunhofer ISE

Solar Thermal Power Plants and Industrial Processes

Already today, concentrating solar thermal power plants (CSP) coupled with large thermal storage units provide dispatchable renewable electricity. Such systems show great potential for industrial systems, increasing efficiency and allowing more flexibility in the energy flows.

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© Fraunhofer ISE

Hydrogen Technologies and Electrical Energy Storage

Our R&D services address the generation, conversion and further thermo-chemical processing of hydrogen. In electrical energy storage, we offer R&D along the entire value chain: from materials, through the cell and module up to the complete battery system.

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© Fraunhofer ISE/Foto: Dirk Mahler

Power Electronics, Grids and Smart Systems

We are working to optimize the interplay between efficient renewable energy generation, the security of supply, energy storage and stable grid operation.

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Dear customers, project partners, sponsors and friends,

Unfortunately, the COVID 19 pandemic continues to keep the world in its grip, presenting us with major challenges and tight constraints. In Germany stricter measures to reduce contact have been put in place since January 2021.

In the new year, Fraunhofer ISE will continue to do everything in its power to protect the health of its employees and society as a whole by acting responsibly. Therefore, we strictly adhere to the official guidelines and those of the Fraunhofer-Gesellschaft and also implement measures which are specific to Fraunhofer ISE. Of course, we remain in operation and continue to serve you. We process all project orders and continue to carry out our R&D for the energy transition. Should there be unavoidable small delays in projects at times due to the measures implemented to contain the infection, we ask for your understanding. We are determined to carry out all work as consistently, quickly and reliably as the current pandemic situation allows. Our employees are working partly at the institute and partly in their home offices. Therefore, please get in touch with your contact person preferably by e-mail. Should you still have difficulties in contacting them, please call our main telephone number: +49 761 4588-0.

We wish you, your relatives and employees good health!

Warm regards,

Prof. Dr. Hans-Martin Henning
Prof. Dr. Andreas Bett

Institute Directors Fraunhofer ISE

R&D for Energy Transition

The Fraunhofer Institute for Solar Energy Systems ISE creates the technological foundations for supplying energy efficiently and on an environmentally sound basis in industrialized, threshold and developing countries. With its research focusing on energy conversion, energy efficiency, energy distribution and energy storage, it contributes to the broad application of new technology.

Fraunhofer ISE develops materials, components, systems and processes in five business areas. In addition to its R&D, the institute offers testing and certification procedures. Furthermore, it features an excellent laboratory infrastructure and is certified according to the quality management standard, DIN EN ISO 9001:2015. Founded in 1981, Fraunhofer ISE, with a staff of over 1200, is the largest solar research institute in Europe.

Current Press Releases


Press Release #9 / 17.5.2021

Monitoring Validates Energy Targets of Freiburg’s New Administration Building “Rathaus im Stühlinger”

After completion in 2017, the city administration building "Rathaus im Stühlinger" in Freiburg was measured and analyzed in detail during the first years of operation. The good news is that the targets set in the planning phase agree with the actual consumption data to a large extent. 


Joint Press Release By Fraunhofer ISE, Öko-Institut And Hamburg Institut / 11.5.2021

How the Building Sector Can Achieve Its Climate Targets After All

The reserach team presents the adequate measures and policy instruments with which decentralized heat generation no longer emits carbon dioxide, final energy consumption can be reduced and heat grids can be expanded.


Press Release #6 / 27.4.2021

The Center for High Efficiency Solar Cells – Fraunhofer ISE Inaugurates New Lab Building

In order to maintain and strengthen its global leadership position in solar energy research, Fraunhofer ISE has now gained a new laboratory building, which was funded in equal parts by the German Federal Ministry of Education and Research BMBF and the State of Baden-Württemberg.


Press Release #5 / 23.4.2021

Tandem Photovoltaics Enables New Heights in Solar Cell Efficiencies – 35.9 % for III-V//Silicon Solar Cell

Freiburg researchers have again succeeded in setting a new world record with a monolithic tandem cell made of III-V and silicon semiconductors.



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News and Events


Trade Fairs, Conferences and Workshops


Fraunhofer ISE’s Planned Spin-Off "PV2plus" Receives Award on World Recycling Day

"Innovative projects and creative ideas for the circular economy and recycling" were distinguished on March 18, 2021 on the occasion of World Recycling Day. The event is held as an initiative of the World Recycling Association and the Bureau of International Recycling (BIR) to highlight the importance of recycling. As part of the event, the Federal Association of the German Waste Management Industry e.V. (BDE), the Federal Association of German Steel Recycling and Disposal Companies e. V. (BDSV) and the Association of German Metal Traders e. V. (VDM) distinguish the most promising circular economy start-ups for their ideas. In the last ten years alone, around 2,400 startups have been founded in the circular economy sector. This year's winners include a spin-off project from Fraunhofer ISE, which was awarded third place for a process already patented in the field of circular economy. The innovation developed at Fraunhofer ISE enables the substitution of silver with copper in the production of silicon heterojunction solar cells.
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H2Demo – Green Hydrogen Produced by Direct Solar Water Splitting

Hydrogen is a storable energy carrier, which makes it an essential component in a fossil-free sustainable energy system. Hydrogen technologies not only serve as a link between the transformations in the energy and mobility sectors but also are important for intelligent energy management and hold a key position in industry’s transition toward a sustainable value chain. The major challenge lies in the sustainable, and thus environmentally friendly, hydrogen production in large quantities. Solar energy plays a central role here. In the joint project "H2Demo", funded by the German Federal Ministry of Education and Research (BMBF) and led by the Fraunhofer Institute for Solar Energy Systems ISE, eleven partners are working on demonstrators for direct solar water splitting.
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Call for papers: DACH+ Conference on Energy Informatics

Organized by the Fraunhofer Institute for Solar Energy Systems ISE and the University of Freiburg, the 10th DACH+ Conference on Energy Informatics will be held in Freiburg, Germany from September 16-17, 2021. It is part of a conference series promoting research, development, and the implementation of information and communication technologies (ICT) in the energy sector. It is intended to foster the exchange in the German-Austrian-Swiss region and neighboring countries (DACH+). The pre-conference 12th Energy Informatics Doctoral Workshop will be held on September 14-15. The organizers seek high-quality original contributions on the topics of smart energy systems, the integration of intermittent renewable generation and energy efficiency gains through ICT, market approaches and mechanisms for ICT-enabled energy systems as well as data-driven decisions.
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Fraunhofer ISE Team Wins Science4Life Energy Cup

The planned spin-off “PV2Plus” of the Fraunhofer Institute for Solar Energy Systems ISE is among the recipients of the Science4Life Energy Cup in the concept phase. At the awards ceremony on March 2, 2021, the PV2Plus research team was awarded for their development of a patented, low-cost electroplating process which will enable solar cell manufacturers to replace conventional silver contacts with copper contacts. This process can help solve the problem of silver availability and reduce costs for solar cell contacting and thus lead to increased solar cell production which is urgently needed for the energy transition. The project team will receive intensive coaching and will be working with industry experts to optimize its business plan.
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Current Posts from "Innovation4E", the Research Blog of Fraunhofer ISE


Scientific Blog of Fraunhofer ISE


We want to share our expertise with you. The scientific blog of Fraunhofer ISE  »Innovation4E« offers a platform for information and exchange.

Research Blog of Fraunhofer ISE


We want to share our expertise with you. The research blog of Fraunhofer ISE  »Innovation4E« offers a platform for information and exchange.

Episode 10 of a series on heat pumps in existing buildings | Marek Miara / 29.4.2021

Is it better to combine a heat pump with fossil heating in some cases?

Episode 9 of a series on heat pumps in existing buildings | Marek Miara / 24.2.2021

Is it worth waiting for technological developments before switching to a heat pump?

Episode 8 of a series on heat pumps in existing buildings | Marek Miara / 14.4.2021

Isn’t heating with heat pumps too expensive?

Episode 7 of a series on heat pumps in existing buildings | Marek Miara / 24.3.2021

How ecological are heat pumps in existing buildings?

Episode 6 of a series on heat pumps in existing buildings I Marek Miara / 17.3.2021

How well have heat pumps performed in practice in unrefurbished buildings?

Episode 5 of a series on heat pumps in existing buildings I Marek Miara / 10.3.2021

How much does the use of back-up heaters reduce the efficiency of heat pumps?