The following is a list of the eligible classifications:
A. Alternative Energy Production
1. Agricultural waste (USPC 44/589).
2. Biofuel (USPC 44/605; 44/589).
3. Chemical waste (USPC 110/235259, 346).
4. For domestic hot water systems (USPC 126/634680).
5. For passive space heating (USPC 52/173.3).
6. For swimming pools (USPC 126/ 561568).
7. Fuel cell (USPC 429/1246).
8. Fuel from animal waste and crop residues (USPC 44/605).
9. Gasification (USPC 48/197R, 197A).
10. Genetically engineered organism (USPC 435/252.3252.35, 254.11254.9,257.2, 325408, 410431).
11. Geothermal (USPC 60/641.2641.5; 436/2533).
12. Harnessing energy from man-made waste (USPC 75/958; 431/5).
13. Hospital waste (USPC 110/235 259, 346).
14. Hydroelectric (USPC 405/7678; 60/495507; 415/25).
15. Industrial waste (USPC 110/235259, 346).
16. Industrial waste anaerobic digestion (USPC 210/605).
17. Industrial wood waste (USPC 44/589; 44/606).
18. Inertial (e.g., turbine) (USPC 290/51, 54; 60/495507).
19. Landfill gas (USPC 431/5).
20. Municipal waste (USPC 44/552).
21. Nuclear powerinduced nuclear reactions: processes, systems, and elements (USPC 376/all).
22. Nuclear powerreaction motor with electric, nuclear, or radiated energy fluid heating means (USPC 60/203.1).
23. Nuclear powerheating motive fluid by nuclear energy (USPC 60/644.1) Photovoltaic (USPC 136/243265).
24. Refuse-derived fuel (USPC 44/552).
25. Solar cells (USPC 438/57, 82, 84,85, 86, 90, 93, 94, 96, 97).
26. Solar energy (USPC 126/561714; 320/101).
27. Solar thermal energy (USPC 126/561713; 60/641.8641.15).
28. Water level (e.g., wave or tide) (USPC 405/7678; 60/495507).
29. Wind (USPC 290/44, 55; 307/6466, 8287; 415/2.1).
B. Energy Conservation
1. Alternative-power vehicle (e.g.,hydrogen) (USPC 180/2.12.2, 54.1).
2. Cathode ray tube circuits (USPC 315/150, 151, 199).
3. Commuting, e.g., HOV, teleworking (USPC 705/13).
4. Drag reduction (USPC 105/1.11.3; 296/180.1180.5; 296/181.5).
5. Electric lamp and discharge devices (USPC 313/498512, 567643).
6. Electric vehicle (USPC 180/65.1;180/65.21; 320/109; 701/22; 310/1310).
7. Emission trading, e.g., pollution credits (USPC 705/3545).
8. Energy storage or distribution (USPC 307/3841; 700/295298; 713/300340).
9. Fuel cell-powered vehicles (USPC 180/65.21; 180/65.31).
10. Human-powered vehicle (USPC 180/205; 280/200304.5).
11. Hybrid-powered vehicle (USPC 180/65.2165.29; 73/35.0135.13, 112115, 116119A, 121132).
12. Incoherent light emitter structure (USPC 257/79, 82, 8890, 93, 99103).
13. Land vehicle (USPC 105/4961 (electric trains); 180/65.165.8 (electric cars)).
14. Optical systems and elements (USPC 359/591598).
15. Roadway, e.g., recycled surface, all-weather bikeways (USPC 404/3246).
16. Static structures (USPC 52/309.1309.17, 404.1404.5, 424442, 783.1795.1).
17. Thermal (USPC 702/130136).
18. Transportation (USPC 361/19, 20, 141, 152, 218).
19. Watercraft drive (electric powered) (USPC 440/67).
20. Watercraft drive (human powered) (USPC 440/2132).
21. Wave-powered boat motors (USPC 440/9).
22. Wind-powered boat motors (USPC 440/8).
23. Wind-powered ships (USPC 114/ 102.1115).
C. Environmentally Friendly Farming
1. Alternative irrigation technique (USPC 405/3651).
2. Animal waste disposal or recycling (USPC 210/610611; 71/1130).
3. Fertilizer alternative, e.g., composting (USPC 71/830).
4. Pollution abatement, soil conservation (USPC 405/15).
5. Water conservation (USPC 137/78.278.3; 137/115.01115.28).
6. Yield enhancement (USPC 504).
D. Environmental Purification, Protection, or Remediation
1. Biodegradable (USPC 383/1; 523/124128; 525/938; 526/914).
2. Bio-hazard, Disease (permanent containment of malicious virus, bacteria, prion) (USPC 588/249249.5).
3. Bio-hazard, Disease (destruction of malicious virus, bacteria, prion) (USPC 588/299).
4. Carbon capture or sequestration (USPC 95/139140; 405/129.1129.95; 423/220234).
5. Disaster (e.g., spill, explosion, containment, or cleanup) (USPC 405/129.1129.95).
6. Environmentally friendly coolants, refrigerants, etc. (USPC 252/7179).
7. Genetic contamination (USPC 422/143).
8. Hazardous or Toxic waste destruction or containment (USPC 588/1261).
9. In atmosphere (USPC 95/5781, 149240).
10. In water (USPC 210/600808; 405/60).
11. Landfill (USPC 405/129.95).
12. Nuclear waste containment or disposal (USPC 588/120, 400).
13. Plants and plant breeding (USPC 800/260323.3).
14. Post-consumer material (USPC 264/36.136.22, 911921; 521/4049.8).
15. Recovery of excess process materials or regeneration from waste stream (USPC 162/29, 189191; 164/5; 521/4049.8; 562/513).
16. Recycling (USPC 29/403.1403.4; 75/401403; 156/94; 264/37.137.33).
17. Smokestack (USPC 110/345; 422/900).
18. Soil (USPC 405/128.1128.9, 129.1129.95).
19. Toxic material cleanup (USPC 435/626282).
20. Toxic material permanent containment or destruction (USPC 588/ all).
21. Using microbes or enzymes (USPC 435/262.5).