| (none) | Collegeville | United States |
| (none) | mastuyamashi | Japan |
| (none) | Tokorozawa | Japan |
| (none) | oobu-shi | Japan |
| (none) | Taipei | Taiwan |
| (none) | Irving | United States |
| (none) | Naperville | United States |
| 1Energy Systems | Seattle | United States |
| ABB | Bethlehem | United States |
| ABB | Västerås | Sweden |
| ABB AG | Mannheim | Germany |
| Abbey Systems | Wellington | New Zealand |
| Administrador del Mercado Mayorista | GUATEMALA | Guatemala |
| Advanced Control Systems Inc. | Norcross | United States |
| advanced energy industries, inc. | Bend | United States |
| Advanced Power Technologies | Randolph | United States |
| Aegis | Vermont | Australia |
| Alabama Power Co. | Birmingham | United States |
| Alstom Grid | Stafford | United Kingdom |
| AltaLink Management LP | Calgary | Canada |
| American Electric Power | Groveport | United States |
| American Superconductor | Middleton | United States |
| Ampcontrol Group | Tomago | Australia |
| Applied Systems Engineering, Inc. | Campbell | United States |
| ARC Informatique | Sevres | France |