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As mentioned previously, the selection of the social criteria selected for the social analysis in this work has been motivated by the following issues:

i) security and diversity of supply; ii) public acceptability;

iii) health and safety; iv) intergenerational issues.

The description of these indicators is given in the following sections. Most of these issues were outlined in Chapter 3 and are discussed for the Mexican power sector in Chapter 8.

i) Security and diversity of supply

Energy security and the diversity of energy supply, along with climate change mitigation, are the most important energy drivers globally and at the country level (IEA/OECD, 2008; 2009; Costantini et al., 2007). Security and diversity of supply is defined as ‗a system‘s ability to provide a flow of energy to meet demand in an economy in a manner and price that does not disrupt the course of the economy‘ (Grubb et al., 2006).

Among the most important factors affecting the security and diversity of supply are: rapid depletion of energy reserves (fossil fuels and uranium), uncertainty of future fossil

fuel prices, together with the disruption of fuel supply because of political conflicts (especially related to oil) or due to intermittency of electricity supply and so affecting the reliability of an electricity system. Fuel import dependency has also become a critical aspect for sustainability of energy systems also because depletion of fossil fuel reserves (Gagnon et al., 2002; Boyle, 2003; Grubb et al., 2006; Costantini et al., 2007; Krewitt et al., 2007; 2009; Greenpeace and EREC, 2008a; IEA/ OECD, 2008; 2009; Kowalski et al., 2009; Lior, 2010).

The IEA/OECD (2008), together with other organizations (e.g. Greenpeace and EREC, 2008a), has argued that, in order to meet security of energy supply for the future, it is essential to promote a diversification of the energy sector based on low carbon technologies. For this reason, the financial support and appropriate energy policies are essential for the development of these technologies (Krewitt et al., 2007; Anderson et al., 2008; Jacobson, 2009; Kowalski et al., 2009; Gallego-Carrera and Mack, 2010; Nakata et al., 2010).

Security and diversity of electricity supply is an important aspect for Mexico since its energy mix is based on fossil fuels and, as discussed in Chapter 2, the existing fossil fuels reserves are insufficient to meet the country‘s demand for more than nine years (Medina-Ross et al., 2005; PEMEX, 2008). Security and diversity of supply is also one of the most important drivers for sustainable development in Mexico, as discussed later Chapter 6 (SENER, 2008).

Aspects considered in this study to assess the security and diversity of electricity supply in Mexico comprise:

 depletion of fossil fuel reserves;  import dependency;

 availability of energy resource; and  reliability of supply.

Depletion of fossil fuel reserves is an important indicator for the security of electricity supply in Mexico because of the fast depletion of fossil fuels reserves and the potential to affect future generations. In this work, abiotic reserve depletion (ADP), calculated as part of LCA, has been used as the indicator to assess this social impact.

Import dependency has also been assessed especially for scenarios based on fossil fuels, based on the assumption that fossil fuels will have to be imported by 2050 to meet Mexico‘s electricity supply (as indicated in Chapter 6). This aspect has become even more critical due to the significant increase of gas imports for electricity production in Mexico (SENER, 2006c; d). Moreover, it is expected that contribution from gas to the electricity mix will increase from 42% today to 55% in 2050. A similar concern applies for coal, expected to increase from 14% to 35% in 2050 (Greenpeace and EREC, 2008b).

Besides fossil fuels, availability of energy resource is also related to the renewable energy potential for electricity generation (Krewitt et al., 2008). This indicator has been discussed for future scenarios with high contribution from renewable energies to the electricity mix. The reliability of an electricity supply system reflects its ability to maintain service continuity which is difficult for intermittent sources such as wind, solar and ocean (Gagnon et al., 2002; Boyle, 2003). Literature does not reveal any methodology for accounting for the reliability of an energy mix; instead power plant availability (the percentage of time that a plant is available to produce electricity) is often used as one measure of reliability (e.g. Chatzimouratidis and Pilavachi, 2009; Stamford and Azapagic, 2011). For the current work, this indicator discusses the possible implication of high contribution of intermittent energy sources to the electricity mix of scenarios.

ii) Public acceptability

Public acceptability is key to implementation of any technology, and therefore, future electricity options (Gagnon et al., 2002; Evans et al., 2009; 2010; Lokey, 2009; Pehnt

and Henkel, 2009; Wang et al., 2009; Gallego-Carrera and Mack, 2010; Onat and Bayar, 2010; Ruiz-Mendoza & Sheinbaum-Pardo, 2010).

This aspect has been considered for all the scenarios according to the public acceptability issues for electricity generating technologies outlined in Chapter 3. For example, main issues affecting the implementation of wind and solar are related to land requirements, visual intrusion, and noise. For large hydro power plants, lack of public acceptance is mainly associated with transformation of land use and relocation of population. Main social concerns for biomass are related to competition for agricultural land, water and food production. In the case of nuclear power, public acceptability is mainly affected by health and safety issues due to the likelihood of nuclear accidents, nuclear proliferation and radioactive waste management and storage. Public acceptance is also an important issue for fossil fuels-based power plants with CCS due to the uncertainty of possible impacts on humans and the environment.

iii) Health and safety

This indicator comprises human health impacts and safety risks and hazards along the life cycle of electricity generating options. These aspects have already been discussed in Chapter 3 for the different electricity technologies. For example, the main health concerns from fossil fuels arise from emissions of SO2, NOx, particulate matter and

heavy metals from the operation of power plants.

Health issues have been quantified in the current work using human toxicity potential (HTP) estimated within LCA. A similar approach has been taken by some other authors, including Dorini et al. (2010) and Stamford and Azapagic (2011).

Safety risks are mostly related to occupational accidents and public hazards (e.g. injuries and fatalities affecting direct workers and the public) and accident risks along their life cycle (e.g. explosions, oil spills, etc.). Similarly, health and safety concerns for nuclear power include nuclear accidents, nuclear proliferation and risk from terrorism as well as

Hammad, 2000; Krewitt et al., 2007; Greenhalgh and Azapagic, 2009; Gallego-Carrera and Mack, 2010; Lior, 2010; Azapagic and Perdan, 2011; Goodfellow et al., 2011). The health and safety issues for different scenarios, with emphasis on fossil fuels and nuclear are discussed in Chapter 8.

iv) Intergenerational issues

Within the sustainable development context (WCED, 1987), intergenerational aspects are referred to problems which affect current and future generations, and therefore addressing these problems is essential (Azapagic and Perdan, 2011).

Some of the most important intergenerational issues, outlined in Chapter 3, include mitigation of climate change and depletion of fossil fuel reserves (Krewitt et al., 2007, 2009; Greenhalgh and Azapagic, 2009; Lior, 2010; Stamford and Azapagic, 2011). In this work, GWP and ADP estimated by LCA, are used to assess these two issues. These indicators have also been used by other authors for the same purposes (e.g. May & Brennan, 2006; Gujba et. al., 2010; 2011). Intergenerational issues associated with long- term nuclear waste management has also been considered as part of this analysis.