| United States Department of Energy |
12,330 |
| BP British Petroleum |
3,585 |
| CH2M HILL Companies, Ltd. |
2,343 |
| Duke Energy Corporation |
2,011 |
| Johnson Controls, Inc. |
1,568 |
| Halliburton Company |
1,482 |
| Exelon Corporation |
1,392 |
| Southern Company |
1,352 |
| Schlumberger Limited |
1,329 |
| Archer-Daniels-Midland Company |
1,269 |
| Entergy Corporation |
1,113 |
| PG&E Corporation |
1,058 |
| Praxair, Inc. |
955 |
| El Paso Corporation |
932 |
| Valero Energy Corporation |
902 |
| Energy Future Holdings |
865 |
| CenterPoint Energy, Inc. |
768 |
| Progress Energy Inc. |
753 |
| Occidental Petroleum Corporation |
736 |
| The Williams Companies, Inc. |
723 |
| Cameron International Corporation |
691 |
| Public Service Enterprise Group Incorporated |
671 |
| Hess Corporation |
671 |
| Pacific Northwest National Laboratory (PNNL) |
656 |
| Devon Energy Corporation |
642 |
| Ameren Corporation |
640 |
| AES Corporation |
620 |
| Kinder Morgan, Inc. |
584 |
| Weatherford International Ltd. |
577 |
| Apache Corporation |
561 |
| Florida DOT |
551 |
| Sunoco, Inc. |
499 |
| Reliant Energy |
478 |
| Arizona Public Service Company |
459 |
| IHS Inc. |
453 |
| Tesoro Corporation |
439 |
| Atmos Energy Corporation |
434 |
| Smith International, Inc. |
429 |
| Petro-Canada |
423 |
| Evonik Degussa Corporation |
423 |
| ONEOK, Inc. |
416 |
| Aker Solutions |
411 |
| BJ Services Company |
407 |
| KBR, Inc. |
407 |
| General Atomics |
372 |
| ICF International, Inc |
359 |
| SRP Salt River Project |
357 |
| Wood Group |
348 |
| Premier, Inc. |
340 |
| CMS Energy Corporation |
331 |
| Dynegy Inc. |
327 |
| Southwest Power Pool |
305 |
| British Columbia Transmission Corporation |
287 |
| SCS Engineers |
279 |
| McJunkin RedMan Corporation |
250 |
| Briggs and Morgan, P.A. |
244 |
| Noble Energy, Inc. |
242 |
| Suncor Energy Inc. |
237 |
| M-I SWACO |
222 |
| Direct Energy Marketing Limited |
218 |
| Talisman Energy Inc. |
211 |
| TNP Enterprises, Inc. |
208 |
| Areva NC Inc |
205 |
| National Energy Board |
201 |
| Day & Zimmermann |
197 |
| Caterpillar Solar Turbines |
193 |
| CONSOL Energy Inc. |
193 |
| Nabors Drilling USA, LP |
192 |
| Pride International, Inc. |
191 |
| Scottish & Southern Energy P.L.C. |
186 |
| M. A. Mortenson Company |
183 |
| Hatch Ltd. |
181 |
| National Rural Electric Cooperative Association |
178 |
| AREVA T&D Inc |
174 |
| Louis Dreyfus Corporation |
169 |
| BNFL |
166 |
| Irving Oil Limited |
165 |
| Union Gas Limited |
162 |
| Wilson |
162 |
| RWD Technologies, Inc. |
161 |
| Air Systems Inc |
160 |
| Sasol North America Inc. |
158 |
| Energy Transfer Partners, L.P. |
157 |
| Samson Investment Company |
156 |
| Plains Exploration |
154 |
| Austin Industries |
154 |
| HAZCO |
154 |
| Bettis Atomic Power Laboratory |
152 |
| Southwire Company |
149 |
| Forest Oil Corporation |
148 |
| American Agip Co., Inc. |
143 |
| American Transmission Company LLC |
141 |
| Flying J Inc. |
140 |
| Ergon, Inc. |
136 |
| Great River Energy |
129 |
| S&C Electric Company |
121 |
| Langan Engineering and Environmental Services, Inc |
120 |
| Cheniere Energy, Inc. |
116 |
| Alpha Technologies |
113 |
| Team Fishel |
113 |
| STP Nuclear Operating Company |
112 |
| Swift Energy Company |
112 |
| ATC Group Services Inc. |
109 |
| Denbury Resources Inc. |
107 |
| Edison Electric Institute |
106 |
| Wachter Corp |
105 |
| Vermont Energy Investment Corporation |
103 |
| Cabot Oil & Gas Corporation |
103 |
| Babcock Power, Inc. |
99 |
| Toronto Hydro Corporation |
98 |
| East Kentucky Power Cooperative |
95 |
| Crosstex Energy, L.P. |
94 |
| Gas Technology Institute |
92 |
| International Resources Group Ltd |
90 |
| Philip Services Corporation (PSC) |
90 |
| Nexant, Inc. |
87 |
| Plug Power Inc. |
86 |
| Global Industries, Ltd. |
86 |
| Cameco Corporation |
85 |
| Veolia Energy North America |
84 |
| Eugene Water |
79 |
| Iberdrola Renewables |
79 |
| Ontario Centres of Excellence Inc. |
79 |
| Clark Nexsen Architecture |
76 |
| Aecon Group Inc. |
75 |
| Petrobras-USA |
75 |
| Alberta Utilities Commission |
75 |
| ENGlobal Corporation |
73 |
| Nsf International |
73 |
| Nuclear Energy Institute |
73 |
| Converteam Inc |
73 |
| Subsea 7 |
72 |
| Energy Advantage Inc |
70 |
| Petrohawk Energy Corporation |
69 |
| Hydril Pressure Control |
69 |
| Rowan Companies, Inc. |
69 |
| EnergySolutions, Inc |
69 |
| Colonial Pipeline Company |
69 |
| Trinity Consultants |
68 |
| Affiliated Engineers, Inc. |
66 |
| Canadian Commercial Corporation |
65 |
| Paradigm Geophysical |
65 |
| American Precision Industries, Inc. |
64 |
| Evergreen Solar, Inc. |
64 |
| TME Inc |
64 |
| Christopher A. Joseph |
64 |
| R.G. Vanderweil Engineers, Inc. |
62 |
| Lansing Board of Water and Light |
62 |
| Comverge, Inc. |
60 |
| C-FER Technologies |
60 |
| Storm Cat Energy Corp |
59 |
| Energy Intelligence Group |
57 |
| Sunflower Electric Power Corporation |
57 |
| Luvata Granada LLC |
55 |
| Institute of Nuclear Power Operations (INPO) |
55 |
| Pike Electric, Inc. |
55 |
| Triten Corporation |
55 |
| Seismic Exchange Inc |
55 |
| Linn Energy LLC |
55 |
| Bill Barrett Corporation |
53 |
| GCIC - Gulf Coast Ignition Corp |
53 |
| Merit Energy Company |
52 |
| Versar, Inc. |
52 |
| SolArc |
52 |
| Morrison Hershfield |
52 |
| First Wind |
52 |
| MSW Managment Magazine |
51 |
| Delta Environmental Consultants, Inc. |
51 |
| Board of Public Utilities of Kansas City, Kansas |
51 |
| Hunting Energy Svc Lp |
51 |
| Petrofac |
51 |
| EPCO, Inc. |
51 |
| Total Safety |
50 |
| Williston Basin Interstate Pipeline Company |
49 |
| Biological Research |
49 |
| Flint Energy Service |
48 |
| BI Nutraceuticals |
48 |
| Sproule Associates Limited |
48 |
| Citation Oil & Gas Corp. |
48 |
| Arctic Slope Regional Corporation |
47 |
| Western Power Distribution Holdings Limited |
47 |
| Northern Power Systems, Inc. |
47 |
| Helmerich & Payne |
46 |
| Motor & Equip.Manufacturers Assoc. |
46 |
| Petroleum Geo-Services |
46 |
| Groupe Tecsult |
45 |
| Alameda County Water District |
45 |
| Country Energy |
45 |
| Origin Energy Shops |
44 |
| National Association of Regulatory Utility Commissioners |
43 |
| Independent Electricity System Operator |
43 |
| Quadrem |
43 |
| Dril-Quip, Inc. |
42 |
| Matrix Service Company |
42 |
| Direct Energy Business |
42 |
| Integrated Service Company LLC |
42 |
| Concentric Energy Advisors |
42 |
| Doble Engineering Company |
41 |
| Edison Welding Institute |
41 |
| Triumvirate Environmental |
41 |
