| Applied Ecology, Inc. | Melbourne, Florida | Visit site |
| Applied Engineering Services | Pune, Maharashtra | Visit site |
| Applied High Voltage, LLC | Albany, New York | Visit site |
| Applied Manufacturing Technologies | Orion, Michigan | Visit site |
| Applied Materials – Picosun | Espoo, Uusimaa | Visit site |
| Apricum – The Cleantech Advisory | Berlin, Berlin | Visit site |
| Apricus Generation | Boca Raton, Florida | Visit site |
| Aptos Solar Technology | San Antonio, Texas | Visit site |
| AqGas Group Limited | Nottingham, England | Visit site |
| Aqua Finance, Inc. | Wausau, Wisconsin | Visit site |
| Aqua Metals, Inc. | Reno, Nevada | Visit site |
| Aquaelecs | Konyaaltı, Antalya | Visit site |
| Aquatera Ltd | Stromness, Scotland | Visit site |
| Aquestia USA | Tulsa, Oklahoma | Visit site |
| Aquila Capital | Hamburg, Hamburg | Visit site |
| Aquora Biosystems | Canton, Michigan | Visit site |
| Arabelle Solutions | Nanterre, Hauts-de-Seine | Visit site |
| Arabian Group Holding (AGH) | Abu Dhabi, Abu Dhabi | Visit site |
| Araoz & Rueda | Madrid, Madrid | Visit site |
| Aras Elektrik Dağıtım A.Ş. | Dundurn, Saskatchewan | Visit site |
| Arausol - Arau Technik GmbH | Schorndorf, Baden-Württemberg | Visit site |
| Arboga kommun | Arboga, Västmanland | Visit site |
| ArcTern Ventures | Toronto, Ontario | Visit site |
| Arca | Vancouver, British Columbia | Visit site |
| Arcadia eFuels | Austin, Texas | Visit site |
| Arcadis | Amsterdam, North Holland | Visit site |
| ArchKey Solutions | Fenton, Missouri | Visit site |
| ArchTech Energy | Glenwood Springs, Colorado | Visit site |
| Archer Wind | Stavanger, Rogaland | Visit site |
| Architectural Solar Association | Boulder, Colorado | Visit site |
| Arconi Solutions | Madrid, Madrid | Visit site |
| Arctech | Sacramento, California | Visit site |
| Ardian | Paris, Île-de-France | Visit site |
| Arena Painting Contractors (APC) | Gardena, California | Visit site |
| Arevia Power | Las Vegas, Nevada | Visit site |
| Argeo | Hvalstad, Akershus | Visit site |
| Argonne National Laboratory | Lemont, Illinois | Visit site |
| Argus Media | London, England | Visit site |
| Aria Holding | Aurora, Colorado | Visit site |
| Arin Power | London, England | Visit site |
| Arina Energy | Dubai, Dubai | Visit site |
| Aristeo | Livonia, Michigan | Visit site |
| Ariston Group | Fabriano, Ancona | Visit site |
| Ariya Finergy | Nairobi, Nairobi | Visit site |
| Arizona Commerce Authority | Phoenix, Arizona | Visit site |
| Arka BRENStech Pvt Ltd | Gurugram, Haryana | Visit site |
| Arkalight Solar | Mandvi Surat, Gujarat | Visit site |
| Arkyne Technologies | Viladecans, Barcelona | Visit site |
| Aro Homes | Sacramento, California | Visit site |
| Arol Energy | Le Bourget-du-Lac, Savoie | Visit site |
| Aros electronics AB | Mölndal, Västra Götaland | Visit site |
| Arowya - Green energy services | Milano, Milan | Visit site |
| Arowya AS | Oslo, Oslo | Visit site |
| Array (ES) | Pamplona, Navarre | Visit site |
| Array Construction Services LLC | Moravia, New York | Visit site |
| Array Technologies | Albuquerque, New Mexico | Visit site |
| Arriba Technologies | Cambridge | Visit site |
| Arteche | Mungia, Biscay | Visit site |
| Artes Group | Kruibeke, East Flanders | Visit site |
| Arthur D. Little | Brussels, Brussels-Capital | Visit site |
| Artisan Electric Inc | Seattle, Washington | Visit site |
| Artisun Solar | Overland Park, Kansas | Visit site |
| Artıbel Belgelendirme Teknik Kontrol Gözetim ve Eğitim Hiz. Ltd. Şti. | Etimesgut, Ankara | Visit site |
| Arvantis Group | München, Bavaria | Visit site |
| Ascend Analytics | Boulder, Colorado | Visit site |
| Ascension Home Solutions | Herriman, Utah | Visit site |
| Ascent Energy Ventures | Denver, Colorado | Visit site |
| Ascent Solar | Thornton, Colorado | Visit site |
| Asepa Energy | Monteiasi, Taranto | Visit site |
| Ashdale | Belfast, Northern Ireland | Visit site |
| Ashdam Solar Company Limited | Oyo | Visit site |
| Ashtrom Renewable Energy | Ramat Gan, Tel Aviv District | Visit site |
| Ashview Consultants | Dublin, Dublin | Visit site |
| Aspect Ecology Ltd. | Oxford, England | Visit site |
| Aspire Consulting | Niagara Falls, Ontario | Visit site |
| Asplundh Tree Expert, LLC | Horsham, Pennsylvania | Visit site |
| Assan Elektronik | Ümraniye, Istanbul | Visit site |
| Asso.subsea | Kifissia, Attica | Visit site |
| Associated Engineering Consultants, Inc. | Wayne, Pennsylvania | Visit site |
| Association of Consulting Engineering Companies BC (ACEC-BC) | Vancouver, British Columbia | Visit site |
| Association of Energy Engineers | Atlanta, Georgia | Visit site |
| Association on Energy Efficiency and Energy Saving in Ukraine | Kyiv, Kyiv | Visit site |
| Associazione Italiana Riscaldamento Urbano - AIRU | Milano, Milan | Visit site |
| Astera Solar | Sandnes, Rogaland | Visit site |
| Asterion Energies | Madrid, Madrid | Visit site |
| Astra Green Solutions | Victoria | Visit site |
| Astral Systems | Bristol, England | Visit site |
| Atalay Grup Enerji A.Ş. | Çankaya, Ankara | Visit site |
| Atama Solar Energy BV | Elst, Gelderland | Visit site |
| Ateios Systems | Newberry, Indiana | Visit site |
| Aterenerji | Bayraklı, İzmir | Visit site |
| Athon | São Paulo, São Paulo | Visit site |
| Atkore | Harvey, Illinois | Visit site |
| Atlantic County Utilities Authority | Egg Harbor Township, New Jersey | Visit site |
| Atlantic Green | London, England | Visit site |
| Atlantic Shores Offshore Wind | Atlantic City, New Jersey | Visit site |
| Atlantis Geoservices Ltd | Norwich, England | Visit site |
| Atlantium Technologies | Central Sulawesi | Visit site |
| Atlasta Solar Center | Grand Junction, Colorado | Visit site |
| AtmoSpark Technologies Inc. | Houston, Texas | Visit site |
| Atmos Consulting Ltd | Edinburgh, Scotland | Visit site |
| AtoMe Inc | Ipswich, Massachusetts | Visit site |
| Atom bv | Melle, East Flanders | Visit site |
| Atonometrics | Austin, Texas | Visit site |
| Attentive Energy | New York, New York | Visit site |
| Attexo Group | Brisbane, Queensland | Visit site |
| Augusta & Co | London, England | Visit site |
| Aurasolar.com | Madrid, Madrid | Visit site |
| Auren Energia | São Paulo, São Paulo | Visit site |
| Aureos | London, England | Visit site |
| Aurora Energy Research | Oxford, England | Visit site |
| Aurora Solar | San Francisco, California | Visit site |
| Ausecology | Brisbane, Queensland | Visit site |
| Australia Wide Solar | Sydney, New South Wales | Visit site |
| Australian Renewable Energy Agency (ARENA) | Canberra, Australian Capital Territory | Visit site |
| Australis Solar | Perth, Western Australia | Visit site |
| Austria Solar | Vienna, Vienna | Visit site |
| Austrian Trade Commission | Vienna | Visit site |
| Autarco | Eindhoven, North Brabant | Visit site |
| Autel Energy | New York, New York | Visit site |
| AutoSep Technologies | Zelienople, Pennsylvania | Visit site |
| Autobat | Tortuguitas, Buenos Aires Province | Visit site |
| Autonics Automation India Pvt. Ltd. | Navi Mumbai, Maharashtra | Visit site |
| Autonometrics | Perth, Western Australia | Visit site |
| Autovert Technologies Pvt Ltd | Bengaluru, Karnataka | Visit site |
| Auttom | Caxias do Sul, Rio Grande do Sul | Visit site |
| Avaada Electro Pvt Ltd | Mumbai, Maharashtra | Visit site |
| Availon United Wind Service | Rheine, North Rhine-Westphalia | Visit site |
| Avalanche Energy | Newcastle, Washington | Visit site |
| Avalon Mechanical | Esquimalt, British Columbia | Visit site |
| Avalon ST / Pasan | Neuchâtel | Visit site |
| Avanceon Middle East & South Asia | Jebel Ali, Dubai | Visit site |
| Avangrid | Orange, Connecticut | Visit site |
| Avantus | San Diego, California | Visit site |
| Avasco Solar | Ieper, West Flanders | Visit site |
| Avfall Sverige | Malmö, Skåne | Visit site |
| Avg Innovation-Connettiamo il mondo al sole attraverso soluzioni nel settore dell'energia solare | Rimini, Rimini | Visit site |
| Avils Consulting Ltd | Bath, England | Visit site |
| Avtron Power Solutions | Cleveland, Ohio | Visit site |
| Axess Power | Doha, Doha | Visit site |
| Axial Solar | Manuel, Valencia | Visit site |
| Axis Renováveis | São Paulo, São Paulo | Visit site |
| Axon' Cable | Fromentières, Marne | Visit site |
| Axtora Energy - Energy Cost Optimization, Waste Heat Conversion to Electrical Energy | Eberswalde, Brandenburg | Visit site |
| Aydem Yenilenebilir Enerji | Merkezefendi, Denizli | Visit site |
| Ayesa | Sevilla, Seville | Visit site |
| Ayming | Levallois-Perret, Hauts-de-Seine | Visit site |
| Ayond | Blomsterdalen, Vestland | Visit site |
| Ayr Energy | Houston, Texas | Visit site |
| Ayrton Energy | Calgary, Alberta | Visit site |