Feminist Contributions to Degrowth

and flow diagrams, discussed in detail in Sections 3.2.2 and 3.2.3 respectively. Preceding this is the problem articulation/boundary selection and the dynamic hypothesis generation. According to Sterman (2000), the formulation of the dynamic hypothesis is a comprehensive process for the inclusion of an initial hypothesis of the problem and mapping of the feedback structures together with their endogenous focus. Hence, the conceptual and simulation model building process requires the problem to be defined dynamically, in terms of graphs over time. The developed model must account for an endogenous, behavioural view of the significant dynamics of the system, focusing on the characteristics of the system that generate or exacerbate the perceived problem/s.

Figure 3.2 shows an example of a typical problem illustrating a variable graphed over time useful for the case study of this thesis. The figure shows the nominal dollar prices of fossil fuel for each of the years considered (it is noted here that the rate of inflation in São Miguel varied between -2%

and 2% over the time period shown (SREA, 2016)).

Figure 3.2 Graph of historical fossil fuel prices for São Miguel (Source: EDA (2016))

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Confirmed from the figure is the issue of increasing fossil fuel prices over the last 15 years. It shows a trend in which the price of fossil fuel used for electricity production has tripled over the last 15 years. This trend is likely to continue into the future and lead to an energy affordability and security problem (Isle-pact, 2012). This problem is combined with the global desires of using less fossil fuel to aid in the mitigation of global warming and re-enforces the usage of more renewables for electricity production. A trend that is evident in the case study electricity system and depicted in the following figure.

Figure 3.3 Graph of historical relative fossil fuel and renewables production (kWh) for São Miguel (Source: EDA (2016))

Figure 3.3 shows the historical trend of fossil fuel and low-carbon renewables usage in São Miguel.

The figure shows that there was a significant drop in fossil fuel usage over the years 2005 to 2008, followed by a more gradual proportionate decline from the 2008 values until 2016. This indicates that the usage trend of fossil fuels and renewables experienced a drastic change but is now appearing to settle. These key variables of fossil fuel prices and the type of electricity generation sources used are good indicators of the general problem for low-carbon electricity systems. In this case study, and in most isolated island systems the price of fossil fuel is external to these systems and a small island without fossil fuel production sources cannot influence these prices. As a consequence high fossil fuel prices are a major problem for such systems and island governments

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have long sought to free themselves of such problems (Weisser, 2004b; Vallvé, 2013). Hence, a choice of low-carbon renewables will help with the global warming issues and ensure the long-term electricity production security of the system (having import independence from fossil fuels), whilst the continued use of fossil fuels will have opposite effects.

Taking this into account, and considering the suggestions of Sterman (2000), the problem articulation of this thesis is centred on the fact that fossil fuels are becoming increasingly unaffordable for island systems that rely on these energy sources. Renewables can provide a solution, but it seems that the advent of high levels of renewables for electricity production is somewhat hindered, as evident in Figure 3.3. This represents a fact that there is a possible problem with the uptake of increasing amounts of renewables within low-carbon electricity systems. Hence this thesis explores policies for sustaining the uptake of renewables needed to ensure energy security (eliminate the dependence on imported fossil fuel for electricity generation) and to understand how this generation capacity mix may be stabilised.

To ensure an accurate representation of this problem, and of the boundaries, the model must be adequately defined. If the model boundary (Sterman, 2000 pg. 97) is too large then the model can be overly complicated. However, if the model boundary is too small then the model can miss important feedbacks and dynamics. Hence, an appropriate and suitable model boundary must be chosen. This is best done as an iterative process whilst examining the problem articulation. In addition, the time horizon required to understand the problem can guide how far into the future the model is extended. It should be able to capture delayed and indirect effects as the system unfolds over time. A suitably long enough time horizon is key for the understanding of the problem and for deciding the model boundary.

In the present case study, the time horizon was determined based on the longest delay of key variables and for capturing long-term trends within the system. The longest time delay for one such key variable are the low-carbon policies (investment goal completion timeline) which are usually

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20 - 30 years in duration. In addition, 2050 is a key year for the timeline of low-carbon transitions based on important worldwide environmental and energy protocols and agreements.

Consequentially, the chosen time horizon is 35 years (2015 - 2050) into the future with 10 years of history (2005 - 2015). Sterman (2000) used a model boundary chart in which he classified model variables as being endogenous (arising from within), exogenous (from outside) and excluded. In this thesis, short-term dynamics (hourly/daily) are widely ignored so variables such as grid frequency balancing and cash flows have been excluded from the model. Some key endogenous variables that have been used are the electricity demand, installed generation capacity for fossil fuel, renewables and energy storage, and adoption of electric vehicles. Key exogenous variables includes GDP and electricity tariffs. More details about the model boundary is shown for the specific sub-models of Chapters 4, 5 and 6.

The general dynamic hypothesis which emerges should be a working theory of how the characterised problem occurs (Sterman, 2000), as intuitively explained by the causal relationships that produce the observed system behaviour. Sterman (2000) also states that this hypothesis should be challenged throughout the modelling process. For this thesis, the initial working theory is that the system is driven by the need to lower CO2 emissions and ensure sustainable electricity supply. Chapters 4, 5 and 6 will challenge this dynamic hypothesis as more causal relationships are discovered and explored. Subsections 3.2.2 and 3.2.3 introduce the necessary SD concepts for diagramming the feedback loops and physical (stock and flow) structures of the system being modelled. The initial working theory as a mental model diagram will be illustrated in the next subsection.