4.3 Primary energy resource potentials, supply chain and conversion technologies
This section discusses primary-supply and secondary-energy (carrier) technologies. Technologies that have developed little since the TAR are covered in detail elsewhere (e.g., IEA, 2006a). Energy flows proceed from primary sources through carriers to provide services for end-users (Figure 4.3). The status of energy sources and carriers is reviewed here along with their available resource potential and usage, conversion technologies, costs and environmental impacts. An analysis is made of the potential contributions due to further technological development for each resource to meet the world’s growing energy needs, but also to reduce atmospheric GHG emissions. Assessments of global energy reserves, resources and fluxes, together with cost ranges and sustainability issues, are summarized in Table 4.2.
Table 4.2: Generalized data for global energy resources (including potential reserves), annual rate of use (490 EJ in 2005), share of primary energy supply and comments on associated environmental impacts.
| Energy class | Specific energy sourcea | Estimated available energy resourceb (EJ) | Rate of use in 2005 (EJ/yr)c | 2005 share of total supply (%) | Comments on environmental impacts |
|---|
| Fossil energy | Coal (conventional) | >100,000 | 120 | 25 | Average 92.0 gCO2/MJ |
| Coal (unconventional) | 32,000 | 0 | | |
| Peatd | large | 0.2 | <0.1 | |
| Gas (conventional) | 13,500 | 100 | 21 | Average 52.4 gCO2/MJ |
| Gas (unconventional) | 18,000 | Small | | Unknown, likely higher |
| Coalbed methane | >8,000? | 1.5 | 0.3 | |
| Tight sands | 8,000 | 3.3 | 0.7 | |
| Hydrates | >60,000 | 0 | | |
| Oil (conventional) | 10,000 | 160 | 33 | Average 76.3 gCO2/MJ |
| Oil (unconventional) | 35,000 | 3 | 0.6 | Unknown, likely higher |
| Nuclear | Uraniume | 7,400 | 26 | 5.3 | Spent fuel disposition |
| Uranium recyclef | 220,000 | Very small | | Waste disposal |
| Fusion | 5 x 109 estimated | 0 | | Tritium handling |
| Renewableg | Hydro (>10 MW) | 60 /yr | 25 | 5.1 | Land-use impacts |
| Hydro (< 10 MW) | 2 /yr | 0.8 | 0.2 | |
| Wind | 600 /yr | 0.95 | 0.2 | |
| Biomass (modern) | 250 /yr | 9 | 1.8 | Likely land-use for crops |
| Biomass (traditional) | | 37 | 7.6 | Air pollution |
| Geothermal | 5,000 /yr | 2 | 0.4 | Waterway contamination |
| Solar PV | 1,600 /yr | 0.2 | <0.1 | Toxics in manufacturing |
| Concentrating solar | 50 /yrh | 0.03 | 0.1 | Small |
| Ocean (all sources) | 7/yr (exploitable) | <1 | 0 | Land and coastal issues. |