| D Square Solar | Jaipur, Rajasthan | Visit site |
| D Volt Co. | Houston, Texas | Visit site |
| D&B Green Solution | Estinnes, Hainaut | Visit site |
| D'Ieteren Energy | Ixelles, Brussels-Capital | Visit site |
| D+R International | McLean, Virginia | Visit site |
| D-GO Mobility | Abrera, Barcelona | Visit site |
| DAC Consulting Services | London, England | Visit site |
| DAHLEM Beratende Ingenieure GmbH & Co. Wasserwirtschaft KG | Essen, North Rhine-Westphalia | Visit site |
| DAS Energy | Ataşehir, Istanbul | Visit site |
| DB Invest Energy | Downers Grove, Illinois | Visit site |
| DBS Cooling Technology (Suzhou) CO., Ltd | Suzhou Shi, Jiangsu | Visit site |
| DC Green Bank | Washington, District of Columbia | Visit site |
| DC Solar Systems | Rolesville, North Carolina | Visit site |
| DC3 | Melbourne, Victoria | Visit site |
| DCE Conseil | Fougères, Ille-et-Vilaine | Visit site |
| DCE Solar | Cornelius, North Carolina | Visit site |
| DCarbon Global | Cairo | Visit site |
| DECAT empowering places | Veurne, West Flanders | Visit site |
| DECO Engineering | Dublin, County Dublin | Visit site |
| DEGSON | West | Visit site |
| DEHN INSTATEC GmbH | Neumarkt in der Oberpfalz, Bavaria | Visit site |
| DEHUI | Singapore, Central Singapore Community Development Council | Visit site |
| DEIF | Skive, Central Denmark | Visit site |
| DEKRA | Stuttgart, Baden-Württemberg | Visit site |
| DEKS Industries Australasia | Melbourne, Victoria | Visit site |
| DENT Instruments, Inc. | Bend, Oregon | Visit site |
| DERINSU Offshore | Beşiktaş, Istanbul | Visit site |
| DES Renewable Energy | Wimborne, England | Visit site |
| DESTEN Inc. | Palo Alto, California | Visit site |
| DEWALT | Towson, Maryland | Visit site |
| DEWETRON | Raaba-Grambach, Styria | Visit site |
| DFI Piling | Edmonton, Alberta | Visit site |
| DG Fuels | Washington, District of Columbia | Visit site |
| DGS Technical Services Inc. | Elgin, Illinois | Visit site |
| DH Engineering | Kalamazoo, Michigan | Visit site |
| DH Technologies, Inc. | Leesburg, Virginia | Visit site |
| DI SOLAR | Rabat, Rabat-Salé-Kénitra | Visit site |
| DIMENSION RENEWABLE ENERGY PRIVATE LIMITED | Bhopal, Madhya Pradesh | Visit site |
| DIN Engineering Services | Noida, Uttar Pradesh | Visit site |
| DIRECT Infrastructure | Sydney, New South Wales | Visit site |
| DIS Fire Systems Pty Ltd | Melbourne, Victoria | Visit site |
| DIS-TRAN Packaged Substations | Pineville, Louisiana | Visit site |
| DIS-TRAN Steel, LLC | Pineville, Louisiana | Visit site |
| DIVESCO INGENIERÍA | Quito, Pichincha | Visit site |
| DIgSILENT GmbH | Gomaringen, Baden-Württemberg | Visit site |
| DJIBOUTI TELLS SOLAR PV-TECH FZE | · | Visit site |
| DK-Automatics | Chennai, Tamil Nadu | Visit site |
| DLM Capital Group | Lagos, Lagos | Visit site |
| DMEGC New Energy Battery - Hengdian Group | · | Visit site |
| DMEGC Solar | Jinhua Shi, Zhejiang | Visit site |
| DMFC Corporation | Fremont, California | Visit site |
| DMG Blockchain Solutions | Delta, British Columbia | Visit site |
| DMS Metering Solutions | Nottingham, England | Visit site |
| DMSolar | League City, Texas | Visit site |
| DNX Energy | Perth, Western Australia | Visit site |
| DOME Serviços Integrados | Rio de Janeiro, Rio de Janeiro | Visit site |
| DOĞUŞ İNŞAAT VE TİCARET A.Ş. | Sarıyer, Istanbul | Visit site |
| DP CleanTech Co. Ltd | Katowice, Silesian Voivodeship | Visit site |
| DRAGADOS OFFSHORE | Puerto Real, Cádiz | Visit site |
| DRAXIS Environmental S.A. | Thessaloniki, Central Macedonia | Visit site |
| DRYCO Construction, Inc. | Fremont, California | Visit site |
| DSI Energy Solutions, LLC | Baton Rouge, Louisiana | Visit site |
| DSPA Aerosol Fire Suppression | Nijmegen, Gelderland | Visit site |
| DTBird & DTBat | Madrid, Madrid | Visit site |
| DTDS Technology Pte Ltd., Marubeni Group | Singapore, South West Community Development Council | Visit site |
| DTSYS Tech LLP - Helping global businesses scale faster and lower overhead costs. | Bhuj, Gujarat | Visit site |
| DWFritz Automation | Wilsonville, Oregon | Visit site |
| DWS Wind Turbine Service | Stradomno, Warmian-Masurian Voivodeship | Visit site |
| DXI Construction | Churchville, Maryland | Visit site |
| DYNEX Arabia | Al Khubar, Eastern | Visit site |
| Dahua Technology | Hangzhou Shi, Zhejiang | Visit site |
| Daikin Industries, Ltd. | 大阪市, Osaka | Visit site |
| Dajcor Aluminum Ltd. | Chatham, Ontario | Visit site |
| Dal Elektrik Motorları Ve Güç Aktarım Sistemleri A.Ş | Bahçelievler, Istanbul | Visit site |
| DalaVind | Falun, Dalarna | Visit site |
| Dalkia | Saint-André-lez-Lille, Nord | Visit site |
| Dalsin Industries | Bloomington, Minnesota | Visit site |
| Damstra Lab | Hengelo, Overijssel | Visit site |
| Danisense A/S | Taastrup | Visit site |
| Danish Wind Supervision | Aalborg, North Denmark Region | Visit site |
| Daphaco | Ho Chi Minh City, Ho Chi Minh City | Visit site |
| Data Engenharia | Ibirité, Minas Gerais | Visit site |
| Data Structures | Blanchardstown, County Dublin | Visit site |
| Datapoint | San Antonio, Texas | Visit site |
| Davis Hill Development | Nashville, Tennessee | Visit site |
| Dawsongroup energy solutions | Milton Keynes, England | Visit site |
| Daxieworld | Er'erduosi Shi, Inner Mongolia | Visit site |
| Daxing International Hydrogen Energy Demonstration Zone | Beijing, Beijing | Visit site |
| Daymark Energy Advisors | Worcester, Massachusetts | Visit site |
| Dazhi Machine Technology | Ningbo Shi, Zhejiang | Visit site |
| De-Source Solar | · | Visit site |
| Decal Renewables | Milano, Milan | Visit site |
| Deep Anchor Solutions Inc. | Houston, Texas | Visit site |
| Deep Fission | Berkeley, California | Visit site |
| Deep South Crane and Rigging, LLC | Baton Rouge, Louisiana | Visit site |
| Deep Wind Offshore | Haugesund, Rogaland | Visit site |
| DeepGreenX | New York, New York | Visit site |
| DefProc Engineering | Liverpool, England | Visit site |
| Degerfors Energi AB | Degerfors, Örebro | Visit site |
| Deligreen Power | Hunan | Visit site |
| Delixi (Hangzhou) Inverter Co., Ltd. | Hangzhou Shi, Zhejiang | Visit site |
| Deloitte | New York, New York | Visit site |
| Delta Electronics (USA) Inc. | 臺北市, Taipei | Visit site |
| Delta Energia | São Paulo, São Paulo | Visit site |
| Delta Global Allied Limited | Pune, Maharashtra | Visit site |
| Delta Green | Praha, Prague | Visit site |
| Delta Solar | Little Rock, Arkansas | Visit site |
| DenAr Ocean Engineering Services SA | Şişli, Istanbul | Visit site |
| Denali Energy Partners | Dallas, Texas | Visit site |
| Denis Doyle Ltd | Grangemellon, Kildare | Visit site |
| Denizüstü Rüzgar Enerjisi Derneği (DÜRED) | Yenimahalle, Ankara | Visit site |
| Denton Solar | Denton, Texas | Visit site |
| Dentons Cardenas & Cardenas | Bogotá, Bogotá | Visit site |
| Departamento de Engenharia Eletrotécnica e de Computadores da NOVA FCT | Caparica, Setúbal | Visit site |
| Department for Energy Security and Net Zero | London, England | Visit site |
| Department of Climate Change, Energy, the Environment and Water | Canberra, Australian Capital Territory | Visit site |
| Derapi | Jackson, Wyoming | Visit site |
| Derun Energy | Canberra, Australian Capital Territory | Visit site |
| DesCor Builders | Roseville, California | Visit site |
| Design Tree Engineering and Land Surveying | Minneapolis, Minnesota | Visit site |
| Design West Engineering | San Bernardino, California | Visit site |
| Design Works Engineering | Edmonton, Alberta | Visit site |
| Designcore Engineering Ltd. | Calgary, Alberta | Visit site |
| Desolenator | Maastricht, Limburg | Visit site |
| Detach Reset Solar | Denver, Colorado | Visit site |
| Determinant Materials, Inc. | Dallas, Texas | Visit site |
| Deutsche Bank | Frankfurt am Main, Hesse | Visit site |
| Deutscher Bauservice GmbH | Cloppenburg, Lower Saxony | Visit site |
| Deutsches Pelletinstitut (DEPI) | Berlin, Berlin | Visit site |
| Devcon Zonnegilde | Kampen, Overijssel | Visit site |
| Dewas Metal Sections Ltd | Dewas Nagar, Madhya Pradesh | Visit site |
| Dewberry | Fairfax, Virginia | Visit site |
| Dewesoft | Trbovlje, Trbovlje | Visit site |
| Dexler Energy Pvt Ltd | Bengaluru, Karnataka | Visit site |
| Deye Service ME | بيروت, Beirut | Visit site |
| Deyle Technik GmbH | Schwalbach am Taunus, Hessen | Visit site |
| DhaSh Group of Companies | Bengaluru, Karnataka | Visit site |
| Dhabi Contracting L.L.C | Abu Dhabi, Abu Dhabi | Visit site |
| Di Mario Électricité Sàrl | Carouge, Geneva | Visit site |
| Diagnostic Photovoltaïque | L'Union, Haute-Garonne | Visit site |
| Diamond Renewable Energy | Arnprior, Ontario | Visit site |
| Dieffenbacher Energy | Bludenz, Vorarlberg | Visit site |
| Digi International | Hopkins, Minnesota | Visit site |
| Digital Energy | Belgrade, Belgrade | Visit site |
| Dikini | Outremont, Quebec | Visit site |
| Dili | New York, New York | Visit site |
| Dimensional Energy | New York, New York | Visit site |
| Dinamica Energia Solar | São Carlos, São Paulo | Visit site |
| Dipro Conduspar Condutores Elétricos | São José dos Pinhais, Paraná | Visit site |
| Direct Wire & Cable | Denver, Pennsylvania | Visit site |