IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group III: Mitigation of Climate Change

Description and assessment of mitigation technologies and practices, options, potentials and costs in the electricity generation sector

The electricity sector has a significant mitigation potential using a range of technologies (Table TS.3). The economic potential for mitigation of each individual technology is based on what might be a realistic deployment expectation of the various technologies using all efforts, but given practical constraints on rate of uptake, public acceptance, capacity building and commercialization. Competition between options and the influence of end-use energy conservation and efficiency improvement is not included [4.4].

Table TS.3: Potential GHG emissions avoided by 2030 for selected electricity generation mitigation technologies (in excess of the IEA World Energy Outlook (2004) Reference baseline) employed in isolation with estimated mitigation potential shares spread across each cost range (2006 US$/tCO2-eq) [Table 4.19].

 Regional groupings Mitigation potential; total emissions saved in 2030 (GtCO2-eq) Mitigation potential (%) for specific carbon price ranges (US$/tCO2-eq avoided) 
<0 0-20 20-50 50-100 >100 
Fuel switch and plant efficiency OECDa 0.39   100       
EITb 0.04   100       
Non-OECD 0.64   100       
World 1.07           
Nuclear OECD 0.93 50 50       
EIT 0.23 50 50       
Non-OECD 0.72 50 50       
World 1.88           
Hydro OECD 0.39           
EIT 0.00           
Non-OECD 0.48 25 35 40     
World 0.87           
Wind OECD 0.45 35 40 25     
EIT 0.06 35 45 20     
Non-OECD 0.42 35 50 15     
World 0.93           
Bio-energy OECD 0.20 20 25 40 15   
EIT 0.07 20 25 40 15   
Non-OECD 0.95 20 30 45   
World 1.22           
Geothermal OECD 0.09 35 40 25     
EIT 0.03 35 45 20     
Non-OECD 0.31 35 50 15     
World 0.43           
Solar PV and concentrated solar power OECD 0.03       20 80 
EIT 0.01       20 80 
Non-OECD 0.21       25 75 
World 0.25           
CCS + coal OECD 0.28     100     
EIT 0.01     100     
Non-OECD 0.20     100     
World 0.49           
CCS + gas OECD 0.09       100   
EIT 0.04     30 70   
Non-OECD 0.09       100   
World 0.22           

Notes:

a) Organization for Economic Cooperation and Development

b) Economies in Transition

A wide range of energy-supply mitigation options are available and cost effective at carbon prices of <20US$/tCO2 including fuel switching and power-plant efficiency improvements, nuclear power and renewable energy systems. CCS will become cost effective at higher carbon prices. Other options still under development include advanced nuclear power, advanced renewables, second-generation biofuels and, in the longer term, the possible use of hydrogen as an energy carrier (high agreement, much evidence) [4.3, 4.4].

Since the estimates in Table TS.3 are for the mitigation potentials of individual options without considering the actual supply mix, they cannot be added. An additional analysis of the supply mix to avoid double counting was therefore carried out. For this analysis, it was assumed that the capacity of thermal electricity generation capacity would be substituted gradually and new power plants would be built to comply with demand, under the following conditions:

The resulting economic mitigation potential for the energy-supply sector by 2030 from improved thermal power-plant efficiency, fuel switching and the implementation of more nuclear, renewables, fuel switching and CCS to meet growing demand is around 7.2 GtCO2-eq at carbon prices <100 US$/tCO2-eq. At costs <20 US$/tCO2-eq the reduction potential is estimated at 3.9 GtCO2-eq (Table TS.4). At this carbon price level, the share of renewable energy in electricity generation would increase from 20% in 2010 to about 30% in 2030. At carbon prices <50 US$/tCO2-eq, the share would increase to 35% of total electricity generation. The share of nuclear energy would be about 18% in 2030 at carbon prices <50 US$/tCO2-eq, and would not change much at higher prices as other technologies would be competitive.

For assessment of the economic potential, maximum technical shares for the employment of low- or zero-carbon technologies were assumed and the estimate is therefore at the high end of the wide range found in the literature. If, for instance, only 70% of the assumed shares is reached, the mitigation potential at carbon prices <100 US$/tCO2-eq would be almost halved. Potential savings in electricity demand in end-use sectors reduce the need for mitigation measures in the power sector. When the impact of mitigation measures in the building and industry sectors on electricity demand (outlined in Chapter 11) is taken into account, a lower mitigation potential for the energy-supply sector results than the stand-alone figure reported here (medium agreement, limited evidence) [4.4].

Table TS.4: Projected power demand increase from 2010 to 2030 as met by new, more efficient additional and replacement plants and the resulting mitigation potential above the World Energy Outlook 2004 baseline [Table 4.20].

 Power plant efficiencies by 2030 (based on IEA 2004a)a (%) Existing mix of power generation in 2010 ( TWh) Generation from additional new plant by 2030 (TWh) Generation from new plant replacing old, existing 2010 plant by 2030 (TWh) Share of mix of generation of total new and replacement plant built by 2030 including CCS at various carbon prices (US$/tCO2-eq)b Total GtCO2-eq avoided by fuel switching, CCS and displacing some fossil fuel generation with low-carbon options of wind, solar, geothermal, hydro, nuclear and biomass 
<20 US$/ TWh <50 US$/ TWh <100 US$/ TWh <20 US$/t <50 US$/t <100 US$/t 
OECD   11,302 2942 4521  7463 1.58 2.58 2.66 
Coal 41 4079 657 1632 889 121       
Oil 40 472  –163C 189 13       
Gas 48 2374 1771 950 1793 637 458       
Nuclear 33 2462 –325 985 2084 2084 1777       
Hydro 100 1402 127 561 1295 1295 1111       
Biomass 28 237 168 95 263 499 509       
Other renewables 63 276 707 110 1116 1544 1526       
CCS         1282 2082       
Economies In Transition (EIT)   1746 722 698   1420   0.32 0.42 0.49 
Coal 32 381 13 152 72 46 29       
Oil 29 69 –8 28 11       
Gas 39 652 672 261 537 357 240       
Nuclear 33 292 –20 117 442 442 442       
Hydro 100 338 35 135 170 170 170       
Biomass 48 47 109 121       
Other renewables 36 10 23 142 167 191       
CCS         123 222       

Notes:

a) Implied efficiencies calculated from WEO 2004 (IEA, 2004b) = Power output (EJ)/Estimated power input (EJ). See Appendix 1, Chapter 11.

b) At higher carbon prices, more coal, oil and gas power generation is displaced by low- and zero-carbon options. Since nuclear and hydro are cost competitive at <20US$/tCO2-eq in most regions (Chapter 4, Table 4.4.4), their share remains constant.

c) Negative data depicts a decline in generation, which was included in the analysis.