**1.1 The greenhouse effect and climate changes**

The greenhouse effect (GHE) that allowed the emergence and expansion of life on earth has been growing due to made-man greenhouse gases (GHG) emissions. The increasing use of fossil fuels since the beginning of the industrial revolution has been increasing the GHE and consequently gradually raising the earth's temperature, affecting the conditions for species survival.

GHGs can be subdivided into two groups: those present in the atmosphere since before the industrial revolution and those that are chemical compounds created and produced by humans. The first group includes carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), whose concentrations in the atmosphere have been rising as a consequence of intensification of human activity. The second group includes perfluorocarbons (PFCs), chlorofluorocarbons (CFCs), hydrofluorcarbons (HFCs), hydrofluorchlorocarbons (HCFCs) and sulfur hexafluoride (SF6). Each of these gases has a different potential to absorb infrared radiation.

Table 1 shows the global warming potential (GWP) over a 100-year horizon of some of the main GHGs (IPCC, 1996). The GWP represents the capacity of a gas present in the atmosphere to absorb energy from infrared radiation.


Table 1. Global Warming Potentials (GWP) (100-Year Time Horizon) - Source: IPCC, 1996

The GWP of each gas is the relative warming potential of that gas in relation to CO2, which has a normalized value of one. For example, N2O has a GWP of 310, meaning its warming

Carbon Capture and Storage – Technologies and Risk Management 239

increasingly relevant. Among the main human activities that contribute to growing CO2

According to the report "CO2 Emissions from Fuel Combustion", published by the International Energy Agency (IEA), in developed countries the use of energy is by far the human activity that produces the most GHG emissions. Figure 1 depicts the distribution of made-man GHG emissions from developed countries (Annex I of the Kyoto Protocol), excluding those generated by changing land use and forestry, which as mentioned before are negative in these countries. The emissions resulting from production, transformation, manipulation and consumption of all types of energy commodities in Annex I countries

emissions are the following:

Extraction of fossil fuels;

Source: IEA (2010a)

natural gas, largely untapped so far.

Thermoelectric plants that burn fossil or other fuels;

Industrial processes that use any type of combustion;

account for 83% of all GHG emissions (IEA,2010a).

 Land, waterborne and aerial vehicles that used combustion engines; Burning to clear land to plant crops or create pastures for animals.

Fig. 1. Shares of made-man GHG emissions in developed countries. Year: 2008.

Figure 2 presents the evolution of the total primary energy supply (TPES) in the world. It can be seen that this doubled between 1971 and 2008. The fact that the share of non-fossil fuels rose from 14% to 19% is due to the increased use of energy from "clean" sources, such as hydroelectric, nuclear and from renewable fuels. Nevertheless, the generation of energy from fossil fuels grew in absolute terms of some 5 gigatonnes of oil equivalent (IEA, 2010a). The increasing energy demand from the growing consumer markets in emerging economies, of which China and Brazil are leading examples, can only be satisfied over the short term by the use of fossil fuels. In this respect, China is stepping up its use of coal to generate electricity, while Brazil has the option in the medium term of using its immense reserves of

The use of renewable fuels, such as ethanol from sugarcane, theoretically has the advantage of not adding new carbon to the atmosphere, since the carbon generated by burning it is

effect is 310 times that of CO2. Although the GWP indicates in exaggerated form the importance of each GHG over the short term in the atmosphere, particularly for methane, it is the standard defined by the IPCC in its Second Assessment Report (SAR) in 1996 and is utilized by the majority of emissions inventories.

Therefore, although nitrous oxide (N2O) and methane (CH4) are present in the atmosphere in much lower concentrations than carbon dioxide and their annual emission levels are far below that of CO2, their molecules have much greater capacity to absorb infrared energy and hence contribute to increase the earth's temperature on the same order of magnitude as CO2.

Table 2 shows the anthropic emissions of GHGs of the United States (US EPA, 2011a) in 2008, the 27 countries of the European Union (EEA, 2010) in 2008 and of Brazil (MCT BRASIL, 2010) in 2005. The emissions of all the gases except for CO2 are expressed by their GWP rather than in absolute mass values. By determination of the United Nations Convention on Climate Change, CFCs and HCFCs are not included in these inventories because they are controlled by the Montreal Protocol, which regulates emissions of gases that destroy the ozone layer. In the case of the United States and European Union (columns 2 to 5 in Table 2), the total emissions are expressed net of the emissions related to changing land use and forestry, which generate negative emissions in these countries. Therefore, changing land use and forestry in these countries cause an increase in the biological capture of CO2, thus acting as carbon sinks. Just to have an idea of the order of magnitude, changing land use and forestry in the United States in 2008 accounted for negative emission of 1,140.5 MtCO2, representing 16% of the total of 6,961.9 MtCO2. In the European Union this negative emission was 256 MtCO2, representing about 8% of the total of 3318 MtCO2.


Sources: US EPA (2011a), EEA (2010) and MCT BRASIL (2010)

Table 2. GHG Emissions – USA and EU – Year: 2008 and Brazil – Year: 2005 (using GWP)

The second emissions inventory carried out in Brazil (MCT BRASIL, 2010) presents the emissions for 1990, 1994, 2000 and 2005. Columns 6 and 7 of Table 2 show the GHG emissions of Brazil in 2005. Unlike columns 2 to 5, the figures in columns 6 and 7 include emissions because of changing land use and forestry. The variation in the percentage shares of CO2 and methane in comparison with those in the United States and European Union is the result of the less intensive industrial activity in Brazil. Besides this, the GWP methodology overstates methane emissions, which have a relatively high value in Brazil due to the importance of farming and stock breeding in comparison with industrial activity.

Until the industrial revolution, natural causes, such as large forest fires caused by lightening and volcanic eruptions, were the main sources of CO2 release. But since the industrial revolution and the expansion of farming and animal husbandry, human activity has become increasingly relevant. Among the main human activities that contribute to growing CO2 emissions are the following:


238 Fossil Fuel and the Environment

effect is 310 times that of CO2. Although the GWP indicates in exaggerated form the importance of each GHG over the short term in the atmosphere, particularly for methane, it is the standard defined by the IPCC in its Second Assessment Report (SAR) in 1996 and is

Therefore, although nitrous oxide (N2O) and methane (CH4) are present in the atmosphere in much lower concentrations than carbon dioxide and their annual emission levels are far below that of CO2, their molecules have much greater capacity to absorb infrared energy and hence

Table 2 shows the anthropic emissions of GHGs of the United States (US EPA, 2011a) in 2008, the 27 countries of the European Union (EEA, 2010) in 2008 and of Brazil (MCT BRASIL, 2010) in 2005. The emissions of all the gases except for CO2 are expressed by their GWP rather than in absolute mass values. By determination of the United Nations Convention on Climate Change, CFCs and HCFCs are not included in these inventories because they are controlled by the Montreal Protocol, which regulates emissions of gases that destroy the ozone layer. In the case of the United States and European Union (columns 2 to 5 in Table 2), the total emissions are expressed net of the emissions related to changing land use and forestry, which generate negative emissions in these countries. Therefore, changing land use and forestry in these countries cause an increase in the biological capture of CO2, thus acting as carbon sinks. Just to have an idea of the order of magnitude, changing land use and forestry in the United States in 2008 accounted for negative emission of 1,140.5 MtCO2, representing 16% of the total of 6,961.9 MtCO2. In the European Union this negative

**USA 2008 EU 2008 Brazil 2005** 

contribute to increase the earth's temperature on the same order of magnitude as CO2.

emission was 256 MtCO2, representing about 8% of the total of 3318 MtCO2.

Sources: US EPA (2011a), EEA (2010) and MCT BRASIL (2010)

Mt CO2 eq. Mt CO2 eq. Mt CO2 eq.

Table 2. GHG Emissions – USA and EU – Year: 2008 and Brazil – Year: 2005 (using GWP)

importance of farming and stock breeding in comparison with industrial activity.

The second emissions inventory carried out in Brazil (MCT BRASIL, 2010) presents the emissions for 1990, 1994, 2000 and 2005. Columns 6 and 7 of Table 2 show the GHG emissions of Brazil in 2005. Unlike columns 2 to 5, the figures in columns 6 and 7 include emissions because of changing land use and forestry. The variation in the percentage shares of CO2 and methane in comparison with those in the United States and European Union is the result of the less intensive industrial activity in Brazil. Besides this, the GWP methodology overstates methane emissions, which have a relatively high value in Brazil due to the

Until the industrial revolution, natural causes, such as large forest fires caused by lightening and volcanic eruptions, were the main sources of CO2 release. But since the industrial revolution and the expansion of farming and animal husbandry, human activity has become

CO2 5.921,400 83,9% 3.062,000 82,3% 1.637,905 74,70% CH4 676,700 9,6% 302,000 8,1% 380,241 17,34% N2O 310,800 4,4% 282,000 7,6% 169,259 7,72% FCs e HFCs 136,000 1,9% 66,000 1,8% 4,593 0,21% SF6 16,100 0,2% 9,000 0,2% 0,602 0,03% Total 7.061,000 100% 3.721,000 100% 2.192,600 100%

utilized by the majority of emissions inventories.


According to the report "CO2 Emissions from Fuel Combustion", published by the International Energy Agency (IEA), in developed countries the use of energy is by far the human activity that produces the most GHG emissions. Figure 1 depicts the distribution of made-man GHG emissions from developed countries (Annex I of the Kyoto Protocol), excluding those generated by changing land use and forestry, which as mentioned before are negative in these countries. The emissions resulting from production, transformation, manipulation and consumption of all types of energy commodities in Annex I countries account for 83% of all GHG emissions (IEA,2010a).

Source: IEA (2010a)

Fig. 1. Shares of made-man GHG emissions in developed countries. Year: 2008.

Figure 2 presents the evolution of the total primary energy supply (TPES) in the world. It can be seen that this doubled between 1971 and 2008. The fact that the share of non-fossil fuels rose from 14% to 19% is due to the increased use of energy from "clean" sources, such as hydroelectric, nuclear and from renewable fuels. Nevertheless, the generation of energy from fossil fuels grew in absolute terms of some 5 gigatonnes of oil equivalent (IEA, 2010a).

The increasing energy demand from the growing consumer markets in emerging economies, of which China and Brazil are leading examples, can only be satisfied over the short term by the use of fossil fuels. In this respect, China is stepping up its use of coal to generate electricity, while Brazil has the option in the medium term of using its immense reserves of natural gas, largely untapped so far.

The use of renewable fuels, such as ethanol from sugarcane, theoretically has the advantage of not adding new carbon to the atmosphere, since the carbon generated by burning it is

Carbon Capture and Storage – Technologies and Risk Management 241

The IEA together with the CSLF (Carbon Sequestration Leadership Forum) prepared a report called "Carbon Capture and Storage – Progress and Next Steps" (IEA & CSLF, 2010) for the G8 summit meeting held in Muskoka, Canada, on June 25-26, 2010. This report lists 80 CCGS projects that fit under a series of criteria, among them the capture of over 500 MtCO2 per year and being in operation between 2015 and 2020. Of these 80 projects, 9 are already in operation and the remaining 71 are in one of the four phases (identification, assessment, definition or execution) that precede operation. Among these 80 projects, 73 are

In a graph, shown in Figure 4, the report predicts growth to as many as 3,400 projects in 2050, of which 65% will be located in countries not belonging to the Organization for Economic Cooperation and Development (OECD). These 3,400 projects will be responsible for capturing some 10 GtCO2 annually, representing a yearly average of 3 MtCO2 per project.

located in developed countries, 4 are in China, 2 in the Middle East and 1 in Africa.

Fig. 4. Global deployment of CCGS 2010-2050 by region – Source: IEA & CSLF (2010)

Fig. 3. Technologies for reducing CO2 emissions - Source: IEA (2010b)

captured from the atmosphere by the plants from which it is produced. However, it is necessary to perform a complete life cycle analysis of the production of renewable fuels such as ethanol. Practices such as burning off litter in cane fields to facilitate harvesting and the use of farm machinery and trucks that burn fossil fuels diminish the comparative advantage, not to mention social questions. Besides this, the use of renewable energy from biofuels in general competes with land use to produce food, to meet the exploding global demand caused by the inclusion in the consumer market of lower classes from densely populated emerging countries like China and India.

Fig. 2. World Primary Energy Supply (TEPS) - Source: IEA (2010a)
