| Orange Solar | Johannesburg, South Africa | Visit site |
| Orano | Paris, France | Visit site |
| Orascom Construction PLC | Cairo, Egypt | Visit site |
| Orbital Marine Power Ltd | Kirkwall, United Kingdom | Visit site |
| Orcan Energy | München, Germany | Visit site |
| Orchid Solar | Edinburgh, United Kingdom | · |
| Ore Energy | Amsterdam, Netherlands | · |
| Oriana Solar Energy Private Limited | Hyderabad, India | Visit site |
| Oriano | Navi Mumbai, India | · |
| Oriens Energy | Sydney, Australia | Visit site |
| Oriens Energía | Villa Constitución, Argentina | Visit site |
| Orient Power | Zhuhai Shi, China | Visit site |
| Orient Solar | Karachi, Pakistan | Visit site |
| Oritia & Boreas | Granada, Spain | Visit site |
| Orizon Energy | Edmonton, Canada | Visit site |
| Orka Solar South Africa | Johannesburg, South Africa | Visit site |
| Orka náttúrunnar / ON Power | Reykjavík, Iceland | Visit site |
| Orkan Automação Industrial | São Bernardo do Campo, Brazil | Visit site |
| Orkan Automação Industrial | Indaiatuba, Brazil | Visit site |
| Orkland Energi | Fannrem, Norway | Visit site |
| Orkuveitan | Reykjavík, Iceland | Visit site |
| Ormazabal | Derio, Spain | Visit site |
| Oryx Power | Madrid, Spain | Visit site |
| Osda Solar | Ningbo Shi, China | Visit site |
| Osnatech GmbH | Bissendorf, Germany | Visit site |
| Oso Polar Energy | Móstoles, Spain | Visit site |
| Ossler Solar | Berlin, Germany | · |
| Otary RS NV | Oostende, Belgium | Visit site |
| Otovo | Oslo, Norway | Visit site |
| Ottawa Electrical Contractors' Association | Ottawa, Canada | Visit site |
| Ottawa Solar Power | Ottawa, Canada | Visit site |
| Ouco | Wuxi Shi, China | Visit site |
| Oulu Electric | China | Visit site |
| Ourolux Iluminação e Energia Solar | Santos, Brazil | Visit site |
| Oushang Photovoltaic | Shijiazhuang Shi, China | Visit site |
| Outdo Battery | Zhangzhou Shi, China | Visit site |
| Outerspace Design | Melbourne, Australia | Visit site |
| Over Easy - Vertical Solar for Rooftops | Oslo, Norway | Visit site |
| Over Easy Solar | Oslo, Norway | Visit site |
| Ownel | Værløse, Denmark | Visit site |
| Oxera Consulting LLP | Oxford, United Kingdom | Visit site |
| Oxera Consulting LLP | Amsterdam, Netherlands | Visit site |
| Oxera Consulting LLP | Berlin, Germany | Visit site |
| Oxera Consulting LLP | Brussels, Belgium | Visit site |
| Oxera Consulting LLP | Hamburg, Germany | Visit site |
| Oxera Consulting LLP | London, United Kingdom | Visit site |
| Oxera Consulting LLP | Madrid, Spain | Visit site |
| Oxera Consulting LLP | Milano, Italy | Visit site |
| Oxera Consulting LLP | Paris, France | Visit site |
| Oxera Consulting LLP | Roma, Italy | Visit site |
| Oxford PV | Oxford, United Kingdom | Visit site |
| OzEnergy A.Ş. | Bornova, Türkiye | Visit site |
| Oze Grup | Ankara, Türkiye | Visit site |
| P.S.P. Specialties Public Company Limited | Mueang Samut Sakhon, Thailand | Visit site |
| P.S.P. Specialties Public Company Limited | Bangkok, Thailand | Visit site |
| P3C Technology and Solutions Pvt Ltd | Narnaul, India | Visit site |
| P4 Solar | Newbridge, United Kingdom | Visit site |
| PA Consulting | London, United Kingdom | Visit site |
| PAC Group | Ballymena, United Kingdom | Visit site |
| PAVANA GmbH | Husum, Germany | Visit site |
| PDL Group | Hexham, United Kingdom | Visit site |
| PE Teknik & Arkitektur | Stockholm, Sweden | Visit site |
| PEAK Wind | Aarhus, Denmark | Visit site |
| PEMA | Brussels, Belgium | Visit site |
| PEP Solar GmbH | Stahnsdorf, Germany | Visit site |
| PERFORMANCE ENGINEERING TUNISIE | Tunisia | Visit site |
| PERI | Weißenhorn, Germany | Visit site |
| PEROVSKIA SOLAR AG | Aubonne, Switzerland | · |
| PES Group | Rosignano Marittimo, Italy | Visit site |
| PES Solar | Bristol, United Kingdom | Visit site |
| PES Wind | Bristol, United Kingdom | · |
| PETRONAS | Kuala Lumpur, Malaysia | Visit site |
| PG Solar LLC | San Rafael, Argentina | Visit site |
| PGE Polska Grupa Energetyczna | Warszawa, Poland | Visit site |
| PGL Environmental Consultants | Vancouver, Canada | Visit site |
| PGL Environmental Consultants | Langley, Canada | Visit site |
| PGL Environmental Consultants | Canada | Visit site |
| PGL Environmental Consultants | Calgary, Canada | Visit site |
| PGL Environmental Consultants | Toronto, Canada | Visit site |
| PH Energies | Fleury-sur-Orne, France | Visit site |
| PHAOS Renewables | Greece | Visit site |
| PHENOGY AG | Root, Switzerland | Visit site |
| PHLEGON SOLAR ENERGY | Vălenii de Munte, Romania | · |
| PHOEBUS ENERGY | Ramat Gan, Israel | Visit site |
| PHOTEOS - Energie Photovoltaïque | Orchies, France | Visit site |
| PHS Solutions | Houghton-le-Spring, United Kingdom | Visit site |
| PIL PERU - Servicios de Ingeniería | Lima, Peru | Visit site |
| PIMEW – Polish Offshore Wind Industry Chamber | Gdynia, Poland | Visit site |
| PIONIERKRAFT | München, Germany | Visit site |
| PIREOS POWER | Mexico City, Mexico | Visit site |
| PIXON | Rajkot, India | Visit site |
| PIZZAROTTI SA | China | Visit site |
| PIZZAROTTI SA | Bellinzona, Switzerland | Visit site |
| PKR Offshore Co., Ltd | 汐止區, Taiwan | Visit site |
| PKR Offshore Co., Ltd | 臺中市, Taiwan | Visit site |
| PLB | Dongwan Shi, China | Visit site |
| PLENR - Onshore & Offshore Wind | Paimpol, France | Visit site |
| PMT | Stadtsteinach, Germany | Visit site |
| PNUC Renewable Energy Co-operative Inc. | Burlington, Canada | Visit site |
| POINT ENERJİ | Çankaya, Türkiye | · |
| PORR Polska | Warszawa, Poland | Visit site |
| POWER TREE | Hassan, India | Visit site |
| POWERCON® | Pune, India | Visit site |
| POWEROAD EUROPE | Düsseldorf, Germany | · |
| POWESCO | Boulogne-Billancourt, France | Visit site |
| PPAM Solkraft | Ljungsbro, Sweden | Visit site |
| PPC Renewables - ΔΕΗ Ανανεώσιμες | Agia Paraskevi, Greece | Visit site |
| PPC S.A. | Brisbane, Australia | Visit site |
| PR Power Engineers Pvt Ltd | Chennai, India | Visit site |
| PRACSIS | Auderghem, Belgium | Visit site |
| PRACSIS | Brussels, Belgium | Visit site |
| PRAGON SOLAR | Altındağ, Türkiye | Visit site |
| PRASARANA MALAYSIA BERHAD | Petaling Jaya, Malaysia | Visit site |
| PRASARANA MALAYSIA BERHAD | Kuala Lumpur, Malaysia | Visit site |
| PREFABBRICATI GUERRINI SRL | Santhià, Italy | Visit site |
| PREsolidsun, s.r.o. | Frýdek-Místek, Czech Republic | Visit site |
| PRODIEL | Sevilla, Spain | Visit site |
| PROINSO Award-Winning Services for Solar Energy Projects | Windsor, United Kingdom | Visit site |
| PRONAGAS - Energías Renovables | Miraflores, Peru | Visit site |
| PROPOINT | Gliwice, Poland | Visit site |
| PROSTER | Brzesko, Poland | Visit site |
| PROTASIS SA | Chalandri, Greece | · |
| PROWATT | Adapazarı, Türkiye | Visit site |
| PRUiM SA - GLIWICE | Gliwice, Poland | Visit site |
| PS Renewables | Basingstoke, United Kingdom | Visit site |
| PSA International | Singapore, Singapore | Visit site |
| PSC Energy | Sydney, Australia | Visit site |
| PSP Dynamic | Bharatpur, India | Visit site |
| PSP Projects Limited | Ahmedabad, India | Visit site |
| PST (Projekt Solartechnik) | Katowice, Poland | Visit site |
| PT CTCI INTERNATIONAL INDONESIA | Jakarta, Indonesia | Visit site |
| PT Datang DSSP Power Indonesia | Akole, India | Visit site |
| PT Datang DSSP Power Indonesia | Jakarta, Indonesia | Visit site |
| PT EIKTO Battery Indonesia | Bekasi, Indonesia | Visit site |
| PT Gree Electric Appliances Indonesia | Jakarta Utara, Indonesia | Visit site |
| PT Penjaminan Infrastruktur Indonesia (Persero) | Jakarta, Indonesia | Visit site |
| PT Sarana Multi Infrastruktur (Persero) | Jakarta, Indonesia | Visit site |
| PT Shenhua Guohua Pembangkitan Jawa Bali | Serang, Indonesia | · |
| PT&I | Sydney, Australia | Visit site |
| PT&I | Canberra, Australia | Visit site |
| PT&I | Adelaide, Australia | Visit site |
| PT(Xiamen)New Energy Co.,Ltd | Xiamen Shi, China | Visit site |
| PT. IDN SOLAR TECH | Batam, Indonesia | · |
| PT. Nusa Solar Indonesia | Batam, Indonesia | Visit site |
| PT. Pantja Putra Mashindo | Bekasi, Indonesia | Visit site |
| PT. VOKSEL ELECTRIC Tbk | Ciamis, Indonesia | Visit site |
| PT. Wedosolar Indonesia | Tangerang Selatan, Indonesia | Visit site |
| PT. Wedosolar Indonesia | Tangerang, Indonesia | Visit site |
| PT1 | Berlin, Germany | · |
| PTI Transformers | Regina, Canada | Visit site |