Scenarios Analysis and Comparative Assessment
The overall demand for energy in the BAU is expected to increase 3.6 times from 2011 to 2611 Mtoe in 2050. The compounded annual growth rate (CAGR) is 3.6 % for the period 2011–2050 which is slower than average GDP growth of 7.0 % which has been assumed for the economy. The decoupling between GDP and energy use is due to both structural changes within the economy (greater share of service sector) and improvement in technological efficiencies. The technological efficiency
Fig. 3.2 Framework for the SLCS
improvement is most significant in the power generation where the net efficiencies improve from around 31.6 % to around 39 % in 2050.
The fuel mix is diversified in the BAU with nuclear energy, gas, and renewables taking a larger share of energy (Fig. 3.3). Coal however continues to remain the mainstay in the BAU scenario, and the bulk of coal is taken for power generation. Coal-based power generation capacity is expected to increase from 117 GW to 700 GW. Nuclear energy takes the next largest share of incremental demand for power generation, and by 2050 the installed capacity for nuclear energy is expected to increase to 200 GW from only 5 GW in 2010.
In the CLCS scenario, high carbon prices are able to bring down overall demand for energy in the medium term (by 2030); however, in the long term, the energy demand is only marginally lower than BAU (Fig. 3.4). A key reason for this is the large penetration of carbon capture and storage (CCS) in combination with coalbased power generation and steel production. CCS technology requires energy for CO2 collection, transportation, and pumping into the storage and therefore imposes an energy penalty. The fuel mix is however diversified in a much stronger fashion with reference to the BAU, and the share of nuclear energy and renewables is much higher (Fig. 3.5).
In the SLCS energy demand is much lower (Fig. 3.4) since the demand for steel, cement, fertilizers, and many other energy-intensive commodities is much lower than BAU due to resource conservation and dematerialization. The energy demand is also lower from building, transport, and commercial sectors due to sustainable lifestyles. By 2050 the overall demand for energy is around one third lower than BAU. The fuel mix is also diversified; however, unlike CLCS, the reliance on nuclear energy and CCS is minimal and consistent with concerns with regard to their sustainability.
Fig. 3.3 Primary energy fuel mix and demand in the BAU
Fig. 3.4 Total primary energy demand in the BAU and low carbon scenarios
CO2 Emissions and Mitigation Options
The CO2 emissions from the energy use in the BAU increase 3.8 times between 2010 and 2050 and reach 7.32 billion tCO2 in 2050. On a per capita basis, the emissions would be around 4.5 tCO2 which is close to the current global average (IEA 2013). The bulk of the CO2 emissions currently are attributable to the combustion of coal (Fig. 3.6), and this scenario would continue in the BAU in the absence of any strong climate policies.
Under both the low carbon scenarios, the growth in emissions can be limited (Fig. 3.7). In the conventional scenario, this is achieved by a small drop in energy demand (Fig. 3.4) and a sharp reduction in the share of coal from 51 % in BAU to 28 % in 2050 (Fig. 3.5). Coal is mainly substituted by nuclear energy and renewables. The share of renewable energy in 2050 is more than double from 9 % in BAU to 20 % in the CLCS (Fig. 3.5). Similarly, the share of nuclear energy is 23 % in 2050 in the CLCS. In addition coal use is increasingly decarbonized within power and steel sector with the introduction of carbon capture and storage (CCS). The total
Fig. 3.5 Fuel mix in low carbon scenarios in 2050
Fig. 3.6 CO2 emissions in the BAU from energy use (million tCO2)
Fig. 3.7 CO2 emissions in the BAU and low carbon scenarios from energy use (million tCO2)
amount of CCS that is sequestered till 2050 is 30.6 billion tCO2. A storage of less than five billion tCO2 is available within depleted oil and gas fields and in coal mines (Holloway et al. 2009), and at many locations, this would be proximal to large point source (Garg and Shukla 2009). The supply curve for CCS therefore allows mitigation at costs below US $ 60 per tCO2 within power and steel sector for a cumulative storage of 5 billion tCO2. Beyond this, we have considered saline aquifers in the sedimentary basin as an option, though there is not much research or government initiative at the moment to identify potential and sites for this. Therefore, increasing CO2 price was considered for this CO2 storage.
In the SLCS scenario, emissions are lower due to a much lower energy demand (Fig. 3.4) from BAU. The lower energy demand is due to a wide variety of measures related to sustainability which reduce demand for energy-intensive industries like steel, cement, bricks, aluminum, etc. The second major driver is renewable energy which provides for one third of primary energy.