| ISCOM SPA - Roofing | Pescantina, Italy | Visit site |
| ISFH – Institut für Solarenergieforschung Hameln | Emmerthal, Germany | Visit site |
| ISG-MOOLEX | Heiligenbrunn, Austria | Visit site |
| ISGroup | Perth, Australia | Visit site |
| ISOLUX CORSAN | Madrid, Spain | Visit site |
| ISS Global Forwarding | Dubai, Brazil | Visit site |
| ITI Powered | Victoria, Canada | Visit site |
| ITS WIND SERVICES LTD | United Kingdom | Visit site |
| ITalConn | Bassano del Grappa, Italy | Visit site |
| IWEN Energy Institute gGmbH | Rostock, Germany | Visit site |
| IWP - Ingenieurbüro für Systemplanung GmbH | Stuttgart, Germany | Visit site |
| IZI Solutions Durables | Courbevoie, France | Visit site |
| IZIVIA - Groupe EDF | Courbevoie, France | Visit site |
| Iberdrola México | General Manuel Ávila Camacho, Mexico | Visit site |
| Iceland Geothermal | Reykjavík, Iceland | Visit site |
| Iceland Renewable Energy Cluster | Reykjavík, Iceland | Visit site |
| Ideal New Energy | Wuxi Shi, China | Visit site |
| Ies Solare S.r.l. | Bibbona, Italy | Visit site |
| Igloo Environmental Limited | Braintree, United Kingdom | Visit site |
| Ijes Solar | Castalla, Spain | Visit site |
| Illuming Power Inc. | Vancouver, Canada | Visit site |
| Ilumisol Energia Solar | Cascavel, Brazil | Visit site |
| Imhotep.Industries | Freistadt, Austria | Visit site |
| Impact Engineering | Smithers, Canada | Visit site |
| Impact Hub Vienna | Vienna, Austria | Visit site |
| Impresa Pizzarotti & C. S.p.A. | Parma, Italy | Visit site |
| Impuls Energy Trading GmbH | Köln, Germany | Visit site |
| InEnergie | Utrecht, Netherlands | Visit site |
| InWarmte | Utrecht, Netherlands | Visit site |
| Inch Cape Offshore Limited | Edinburgh, United Kingdom | Visit site |
| Inclusive Green Growth in Egypt النمو الأخضر الشامل فى مصر | Piraquara, Brazil | · |
| Increase New Energy (Hunan) Co.,Ltd | China | Visit site |
| Incubateur Savoie Technolac | Le Bourget-du-Lac, France | Visit site |
| Independent Electricity System Operator (IESO) | Toronto, Canada | Visit site |
| India Agrivoltaics Alliance (IAA) | India | Visit site |
| Indigenous Services Canada | Services aux Autochtones Canada | Gatineau, Canada | Visit site |
| Indo-German Energy Forum Support Office (IGEF-SO) | New Delhi, India | Visit site |
| Indonesia Infrastructure Finance | Jakarta, Indonesia | Visit site |
| Induscabos | Poá, Brazil | Visit site |
| Industrial Batteries Australia | Adelaide, Australia | Visit site |
| Infineon Technologies | Neubiberg, Germany | Visit site |
| InfraCredit | Nigeria | Visit site |
| InfraRoad Trading & Contracting LLC | Al-Riyadh, Qatar | Visit site |
| InfraVia Capital Partners | Paris, France | Visit site |
| Infranity | Paris, France | Visit site |
| Infyos | London, United Kingdom | Visit site |
| Ingenergía de México | San Juan Tehuixtitlán, Mexico | Visit site |
| Ingenieurbüro GEHLEN | Düsseldorf, Germany | Visit site |
| Ingenieurgesellschaft IDEAS mbH | Thundorf in Unterfranken, Germany | Visit site |
| Ingenieurgesellschaft Mengü Ingenieure GmbH | Hamm, Germany | Visit site |
| Initiative Klimabetrug Stoppen e.V. | Berlin, Germany | Visit site |
| Innergex | Longueuil, Canada | Visit site |
| Inno Energy Group | Sydney, Australia | Visit site |
| InnoVent | Villeneuve-d'Ascq, France | Visit site |
| Innova Sun | San Francisco del Rincón, Mexico | Visit site |
| Innovations Bangalore | Chitradurga, India | Visit site |
| Innovcable | Dois Córregos, Brazil | Visit site |
| Innowell Group | Bengaluru, Australia | Visit site |
| Innowind Energy Solutions | Cambridge, Canada | Visit site |
| Innpact | Luxembourg | Visit site |
| Inpasa | Brazil | Visit site |
| Inscio Roofs | IJsselstein, Netherlands | Visit site |
| Inspire Clean Energy | Chennai, India | Visit site |
| Insta GmbH | Lüdenscheid, Germany | Visit site |
| Installatøren Gruppen | Oslo, Norway | Visit site |
| Institut National de l'Économie Circulaire (INEC) | Paris, France | Visit site |
| Institut Photovoltaïque d'Ile-de-France (IPVF) | Düsseldorf, Germany | Visit site |
| Instrumentos y Controles S.A. | Bogotá, Colombia | Visit site |
| IntES International Engineering Solutions | Amsterdam, Netherlands | Visit site |
| Intecsa | Madrid, Spain | Visit site |
| Integral RISE | Ismailia, Egypt | Visit site |
| Integrum Energy | Bengaluru, India | Visit site |
| IntelliSpatial | Perth, Australia | Visit site |
| InterContinental Energy | Singapore | Visit site |
| Interlink Alternative Energy | Parklands, Australia | Visit site |
| Interpath | London, United Kingdom | Visit site |
| Intertechne | Belo Horizonte, Brazil | Visit site |
| Intherpro LLC | Brazil | Visit site |
| Intrax Consulting Group | Melbourne, Australia | Visit site |
| Inventronics | Hangzhou Shi, China | Visit site |
| Inventum Technologies B.V. | Houten, Netherlands | Visit site |
| Investerra AG | St. Gallen, Switzerland | Visit site |
| Investment Management Corporation of Ontario (IMCO) | Toronto, Canada | Visit site |
| Invicto Energia Solar | Maringá, Brazil | Visit site |
| Ipvisola Norge as | Ågotnes, Norway | Visit site |
| Irish Solar Energy Association (ISEA) | Dublin, Ireland | Visit site |
| Isifloating | Beneixama, Spain | Visit site |
| Isii-Tech | Saint-Étienne-du-Rouvray, France | Visit site |
| Isoeste Construtivos Isotérmicos Ltda. | Anápolis, Brazil | Visit site |
| Isotec Enerji | Dilovası, Türkiye | Visit site |
| Italian Geothermal Forum | Milano, Italy | Visit site |
| Ivosis Group | Erlangen, Germany | Visit site |
| J&F Biogas | Bengaluru, India | Visit site |
| J&L Build | Potters Bar, United Kingdom | Visit site |
| JAHA Solar | Fushë Kosova, Kosovo | Visit site |
| JEPA | Athina, Greece | Visit site |
| JERA Nex | London, United Kingdom | Visit site |
| JIANGXI TIANZE POWER SUPPLY CO.,LTD. | Yichun Shi, China | Visit site |
| JLA Hydro | Assesse, Belgium | Visit site |
| JMC Projects (India) Ltd | Mumbai, India | Visit site |
| JOANNEUM RESEARCH | Graz, Austria | Visit site |
| JPM Silicon | Braunschweig, Germany | Visit site |
| JSC AtomStroyExport | Moscow, Russia | Visit site |
| JT Energy Systems GmbH | Freiberg, Germany | Visit site |
| JUMO Schweiz | Switzerland | Visit site |
| Jadeed | Cairo, Egypt | Visit site |
| Jan De Nul Group | Capellen, Luxembourg | Visit site |
| Janitza electronics GmbH | Lahnau, Germany | Visit site |
| Java Holdings Ltd | Edmonton, Canada | Visit site |
| Jiangsu Davinsolar Aluminium Technology Co., Ltd | Wuxi Shi, China | Visit site |
| Jiangsu Gomon New Energy Co.,Ltd | Taizhou Shi, China | Visit site |
| Jiangsu Yawei Transformer Co., Ltd | China | Visit site |
| Jimmy | Paris, France | Visit site |
| JinenU Solar | Taizhou Shi, China | Visit site |
| Jinergy | Jingzhong Shi, China | Visit site |
| Jingdao New Energy | Qingdao Shi, China | Visit site |
| Jingxin Science and Technology | Tangshan Shi, China | Visit site |
| JinkoCn | Shenzhen Shi, China | Visit site |
| Jinrun Electronics Co., Ltd. | China | Visit site |
| Jinyou Jinhong | Shanghai, China | Visit site |
| JnTech | Hefei Shi, China | Visit site |
| John Cullen Lighting | London, United Kingdom | Visit site |
| John Laing | London, United Kingdom | Visit site |
| John Sisk & Son Ltd | Tallaght, Ireland | Visit site |
| Jones Engineering | Dublin, Ireland | Visit site |
| Joule Group | Belfast, Ireland | Visit site |
| Junna Solar | Hyderabad, India | Visit site |
| Jupiter International Limited | Baddi, India | Visit site |
| Jurong Engineering Limited | Singapore | Visit site |
| Juxin Energy | Wuxi Shi, China | Visit site |
| K-Electric | Karachi, Pakistan | Visit site |
| K. LIAROMATIS S.A. | Agios Stefanos, Greece | Visit site |
| KALPATARU POWER TRANSMISSION LIMITED | Mumbai, India | Visit site |
| KALPATARU PROJECTS INTERNATIONAL LIMITED | Mumbai, India | Visit site |
| KAM | Mexico City, Mexico | Visit site |
| KAMATI LTDA. BIC. | Bogotá, Colombia | Visit site |
| KB Development srl | Civitanova Marche, Italy | Visit site |
| KEC International Ltd. | Mumbai, India | Visit site |
| KEI Wires and Cables | New Delhi, India | Visit site |
| KEMA Labs | Arnhem, Czech Republic | Visit site |
| KERSTEN | Wanssum, Netherlands | Visit site |
| KGAL GmbH & Co. KG (KGAL) | Grünwald, Germany | Visit site |
| KIENLE Beratende Ingenieure GmbH | Konstanz, Germany | Visit site |
| KIMSEN Aluminum | Yên Phong, Vietnam | Visit site |
| KIN HOMES | New Zealand | Visit site |
| KIS Group-Sustainability² | Bengaluru, India | Visit site |
| KISTERS HydroMet | Aachen, Germany | Visit site |
| KJTS Group Berhad | Kuala Lumpur, Malaysia | Visit site |
| KK Group | Ikast, Denmark | Visit site |
| KLAAFE Engineering Services | Hull, United Kingdom | Visit site |