- acatech – Deutsche Akademie der Technikwissenschaften, member
- Agentur für Erneuerbare Energien AEE, member
- Alliance for Rural Electrification, member
- American Society of Heating, Refrigerating and Air-Conditioning Engineers ASHRAE, member
- Bavaria California Technology Center (BaCaTec), board of trustees
- Brennstoffzellen- und Batterie-Allianz Baden-Württemberg, (BBA-BW), member and chairman
- Bundesverband Energiespeicher (BVES),member and chairmanship
- Bundesverband Kraft-Wärme-Kopplung (B.KWK), member
- Bundesverband Solarwirtschaft (BSW)
- Arbeitskreis »Ländliche Elektrifizierung«, member
- Fachgruppe »Netzfragen«, member
- Arbeitskreis »Speicher«, member
- CAN in Automation (CiA), member
- CPV-Consortium, Board of Directors, member
- Dechema
- Temporärer Arbeitskreis MOF, member
- Temporärer Arbeitskreis Thermische Energiespeicherung, member
- Desertec Industrial Initiative (Dii), associate partner
- Deutsche Gesellschaft für Kristallwachstum und Kristallzüchtung e.V.
- Deutsche Gesellschaft für Sonnenenergie e. V. (DGS), member
- Deutscher Kalibrierdienst DKD
- Fachausschuss Hochfrequenz und Optik, member
- Deutscher Kälte- und Klimatechnischer Verein e. V. (DKV), member
- Deutsche Kommission Elektrotechnik Elektronik Informationstechnik in DIN und VDE (DKE)
- Ad-hoc-Arbeitskreis »Blitz- und Überspannungsschutz für Photovoltaik-Anlagen«
- Arbeitsgruppe »Portable Fuel Cell Systems«
- Arbeitskreis 221.1.4 »Errichtung von Photovoltaik-Anlagen nach DIN VDE 0100-712«
- Arbeitskreis Brandschutz VDE-AR-E 2100-712 »Anforderungen zur Freischaltung im DC-Bereich einer PV-Anlage«
- Komitee 373 »Photovoltaische Solarenergiesysteme«
- Arbeitskreis 373.0.2 »Gebäudeintegrierte PV-Module«
- Komitee 374 »Solarthermische Anlagen zur Stromerzeugung«
- Komitee 384 »Brennstoffzellen«
- Komitee 213 »Brandbekämpfung in elektrischen Anlagen«
- Deutsche Meerwasserentsalzung e.V. (DME), member
- Deutsche Physikalische Gesellschaft (DPG)
- Arbeitskreis Energie, member
- Deutsche Solarthermie Technologieplattform (DSTTP), member
- Deutsches Institut für Normung e. V. (DIN)
- Fachnormenausschuss Heiz- und Raumlufttechnik (NHRS AA1.56) »Solaranlagen«, member
- Fachnormenausschuss Lichttechnik (FNL 6) »Innenraumbeleuchtung mit Tageslicht«, member
- DIN-Spiegelausschuss, NA 041-01-56 AA Arbeitsausschuss Solaranlagen
- Erfahrungsaustauschkreis der Prüfstellen Thermischer Solaranlagen und ihrer Bauteile EKTSuB des DIN, deputy chairman
- Deutsch-französisches Büro für Erneuerbare Energien (DFBEE), member
- e-mobil BW
- Energy Efficient Building Association (E2BA), member
- EU PV Technology Platform
- Steering Committee, member
- Expert Pool, member
- Europäisches Komitee für Normung (CEN)
- TC33/WG3/TG5 »Thermal and Visual Comfort«, member
- TC129/WG9 »Light and Energy Transmission, Thermal Insulation«, member
- TC169/WG11 »Daylighting in Buildings«, member
- TC312/WG1/WG2/WG3 »Solar Collectors«/» Factory Made Systems«/»Thermal Solar Systems and Components; Custom Built Systems«, member
- CENELEC TC82 WG1 on prEN 50583 »Photovoltaics in Buildings« - chairman, member and Components; Custom Built Systems«, member
- European Academy, Institute for Renewable Energy (Bolzano/Italy), member of scientific board
- European Energy Research Alliance (EERA)
- Joint Programme Concentrated Solar Power (CSP)
- Joint Programme Smart Cities, member
- European Center for Power Electronics e. V. (ECPE), member
- European Committee for Electrotechnical Standardization (CENELEC)
- TC82/WG 1 »Wafers, Cells and Modules« – NWIP »BIPV«, chairmanship and member
- Workshop 5 »Flow Batteries – Requirements and Test Methods«, member
- European H2/FC Technology Platform, member
- European Heat Pump Association (EHPA), member
- European Solar Thermal Electricity Association (ESTELA), member sowie Scientific Technical Committee, member
- European Solar Thermal Industry Federation (ESTIF), member
- European Technology Platform on Renewable Heating and Cooling (RHC-platform), chairman
- European Photovoltaic Industry Association (EPIA), associate member
- European Photonics Industry Consortium (EPIC), member
- European Power Electronics and Drives Association (EPE), member
- European Solar Thermal Technology Panel (ESTTP)
- EuroSolar: The European Association for Renewable Energy
- Association of European Renewable Energy Research Centres (EUREC), chairman
- Fachinstitut Gebäude-Klima (FGK), member
- Fachverband Transparente Wärmedämmung e. V., member
- fesa Förderverein Energie- und Solaragentur Regio Freiburg e.V.
- FitLicht – Fördergemeinschaft innovative Tageslichtnutzung, member
- Fördergesellschaft Windenergie und andere Erneuerbare Energien (FGW) e. V.
- Arbeitskreis »Photovoltaik«, cooperation
- Arbeitskreis »TR3 – Elektrische Eigenschaften und Erzeugungseinheiten«
- Arbeitskreis »TR4 – Modellierung und Validierung von Simulationsmodellen«
- Arbeitsgruppe »Oberschwingungen«
- ForschungsVerbund Erneuerbare Energien (FVEE), member
- Fraunhofer-Systemforschung Elektromobilität, member
- Fraunhofer-Themenverbund Werkstoffe und Bauteile, member
- Freiburger Verein für Arbeits- und Organisationspsychologie (FVAO), chairman
- Fuel Cell Europe, member
- German Facility Management Association (GEFMA)
- Richtlinienausschuss GEFMA 122 Betriebsführung im Facility Management
- German Scholars Organization (GSO), chairman
- Gesellschaft für Umweltsimulation (GUS)
- Arbeitskreis »Batterieprüfung«, member
- Global Village Energy Partnership (GVEP), member
- Go100%, member
- Green Chiller Verband für Sorptionskälte e. V. , member
- Interessengemeinschaft für Batterien in Elektrischen Netzen, member
- International Advisory Committee of EUPVSEC, member
- International Advisory Committee of SIMC, member
- International Commission on Glass
- TC10 »Optical Properties and Characterization of Glass«, member
- International Commission on Illumination CIE
- TC3-39 »Discomfort Glare from Daylight in Buildings«, member
- TC3-47 »Climate-Based Daylight Modelling«, member
- International Electrotechnical Commission IEC
- TC82 »Solar Photovoltaic Energy Systems«, WG3/WG7, member
- TC82 »Modules, non-concentrating«, WG2,
- TC105 »Fuel Cell Technologies«, WG7/WG11, member
- TC117 »Solar Thermal Electric Plants«, member
- International Energy Agency IEA, cooperation
- Energy Conservation in Buildings and Community Systems Programme EBC
- Annex 60 »New generation computational tools for building and community energy systems based on the Modelica and Functional Mockup Interface standards«
- Energy Conservation Through Energy Storage Programme ECES
- Annex 24 »Compact Thermal Energy Storage – Material Development for System Integration«
- Heat Pump Programme HPP
- Annex 32 »Economical Heating and Cooling Systems for Low Energy Houses«
- Annex 38 »Solar and Heat Pump Systems – Systems Using Solar Thermal Energy in Combination with Heat Pumps«
- Annex 42 »Heat Pumps in Smart grids«
- Annex 43 »Fuel-driven sorption heat pumps«
- Annex 45 »Hybrid heat pumps«
- Photovoltaic Power Systems Programme (PVPS)
- Task 9 »Development of PV Services for Regional Development«
- Task 11 »PV Hybrids and Mini-grids«
- Solar Heating & Cooling Programme SHCP
- Task 38 »Solar Air-Conditioning and Refrigeration«
- Task 39 »Polymeric Materials for Solar Thermal Applications«
- Task 43 »Solar Rating and Certification Procedure – Advanced Solar Thermal Testing and Characterization for Certification of Collectors and Systems«
- Task 44 »Solar and Heat Pump Systems – Systems Using Solar Thermal Energy in Combination with Heat Pumps«
- Task 47 »Renovation of Non-Residential Buildings towards Sustainable Standards«
- Task 48 »Quality Assurance and Support Measures for Solar Cooling«
- Task 49 »Solar Process Heat for Production and Advanced Applications«
- Task 51 »Solar Energy in Urban Planning«
- Task 52 »Solar Heat and Energy Economy in Urban Environments«
- Energy Conservation in Buildings and Community Systems Programme EBC
- International Programme Committee of GADEST, member
- International Renewable Energy Agency (IRENA)
- International Renewable Energy Storage Conference and Exhibition IRES, Programme Commitee
- International Science Panel on Renewable Energies (ISPRE), chairmanship
- International Solar Energy Society ISES
- International Standardization Organization ISO
- TC 163 Normung von kalorimetrischen g-Wert-Prüfungen, WG 17
- TC180 Solar Energy, WG2/WG5, member
- Intersolar North America, Programme Commitee, chairmanship and member
- Kompetenzfeld Photovoltaik NRW, member
- Kompetenznetzwerk Brennstoffzelle NRW, member
- Leibniz-Institut für Kristallzüchtung IKZ, advisory board
- Lichttechnische Gesellschaft, member
- Fachausschuss Tageslicht
- Mikrosystemtechnik Baden-Württemberg (MST-BW), advisory board
- Monitoring and Evaluation Working Group (M&EED) by Global Village Energy Partnership (GVEP) and European Union Energy Initiative (EUEI), member
- Photonics Baden-Württemberg, member
- Scientific Commission to the ENI Science and Technology Award, member
- SEMI International, Board of Directors, member
- SEMI Standardisation task PV Production
- SEMI Standards, Photovoltaic Equipment Interface Specification Task Force (PV-EIS), member
- SHC Conference
- Solar Cluster Baden-Württemberg e.V. , member and managing board
- Solar Energy Research Institute of Singapore (SERIS), advisory board
- Solar Keymark Network, member
- Solar Power and Chemical Energy Systems SOLARPACES
- Task I »Solar Thermal Electric Systems«
- Task III »Solar Technology and Advanced Applications«
- Smart Grid Plattform Baden-Württemberg, member
- SolarValley Mitteldeutschland, member and chairman
- SPIE Reliability of PV-Modules
- Stiftung Solarenergie, advisory board
- Symposium Photovoltaische Solarenergie, OTTI Technologie-Kolleg, scientific advisory board
- Symposium PV Hybrid und Minigrid, OTTI Technologie-Kolleg, scientific advisory board
- Symposium Small PV Applications, OTTI Technologie-Kolleg, scientific advisory board
- Symposium Thermische Solarenergie, OTTI Technologie-Kolleg, scientific advisory board
- User Forum »ThinFilmPhotovoltaics«, scientific advisory board
- VDE Forum Netztechnik/Netzbetrieb (VDE-FNN)
- Projektgruppe »Blindleistung«, member
- VDI-Gesellschaft Energie und Umwelt (VDI-GEU)
- Fachausschuss Regenerative Energien (FARE), member
- Richtlinienausschuss VDI 3988 - Solarthermische Prozesswärme
- Richtlinienausschuss VDI 4645 (VDI-Gesellschaft Energie und Umwelt
- Richtlinienausschuss VDI 4650, Blatt 1 und 2 (VDI-Gesellschaft Energie und Umwelt
- VDI-Gesellschaft Technische Gebäudeausrüstung (VDI-TGA)
- Richtlinienausschuss 3789 »Energie und Umwelt«
- Richtlinienausschuss 4706 »Kriterien für das Innenraumklima«
- Richtlinienausschuss 4650, Blatt 1 und Blatt 2 »Wärmepumpen«
- Richtlinienausschuss 4645, »Planung und Dimensionierung von Wärmepumpen von Heizungsanlagen mit Wärmepumpen in Ein- und Mehrfamilienhäusern«
- Richtlinienausschuss 2164 »Latentspeichersysteme«
- Richtlinienausschuss 6018 »Kälteversorgung in der TGA – Planung, Bau, Abnahmeprüfung, Betrieb, energetische Bewertung«
- VDMA – The German Engineering Federation
- Arbeitskreis 24247 »Energie-Effizienz von Kälteanlagen«
- Productronics Association, member
- Deutsches Flachdisplay-Forum (DFF), member
- Organic Electronics Association (OE-A), member
- Verband der Deutschen CSP, Deutsches Industrienetzwerk Concentrated Solar Power, member
- Verein Forum Elektromobilität, member of advisory board