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1 | 1 | Solving climate change will require our globalized society to transition from |
2 | 2 | fossil fuel infrastructure to clean energy infrastructure. This transition must |
3 | 3 | also be done equitably and justly to prevent entrenching further injustices to |
4 | | -marginalized and vulnerable communities. An economy-wide transition presents a |
5 | | -challenge unto itself due to the spatial, temporal, and topological complexities |
6 | | -of energy systems. Energy system optimization models (ESOMs) are a class of |
7 | | -tools designed to optimize this transition used by energy planners and |
8 | | -decision-makers to generate insights that inform policy. However, ESOMs have a |
9 | | -few critical gaps. First, current ESOMs exclusively optimize on cost, yet real |
10 | | -world decisions are also informed by non-financial priorities, such as |
11 | | -sustainability and social benefits. Since these objectives cannot be neatly |
12 | | -captured by a cost metric, ESOMs fail to optimize for these goals. Second, ESOMs |
13 | | -struggle to meaningfully incorporate concepts of justice. Some studies model |
14 | | -distributive justice --- related to the way benefits and burdens are shared |
15 | | -among society's members --- but do so in an \textit{ex post} fashion. Procedural |
16 | | -justice and recognition justice --- aspects of justice related to the |
17 | | -policymaking process and context in which decisions are made --- are frequently |
18 | | -sidelined. Indeed, ESOMs may be misused during a policymaking process to dismiss |
19 | | -public input for lack of rigor. This thesis attends to these flaws in ESOM tools |
20 | | -by developing the first multi-objective energy system optimization framework, |
21 | | -\texttt{Osier}. |
22 | | - |
23 | | -Rather than returning a single optimal solution, multi-objective optimization |
24 | | -generates a set of co-optimal solutions called a \textit{Pareto front}, where no |
25 | | -objective can be improved without making another objective worse. The existence |
26 | | -of a Pareto front evinces tradeoffs which can only be resolved through dialogue |
27 | | -in a participatory process. \texttt{Osier} allows users to optimize arbitrarily |
28 | | -many objectives and define new objectives to create a bespoke, contextualized, |
29 | | -model. This thesis recognizes that some structural uncertainty will persist |
30 | | -regardless of the number of objectives. Thus, \texttt{Osier} leverages genetic |
31 | | -algorithms for their ability to sample complex Pareto fronts and because their |
32 | | -search methods automatically sample sub-optimal space. Further, this thesis |
33 | | -develops a novel algorithm to calculate a subset of maximally different |
34 | | -solutions within the sub-optimal space to address this uncertainty related to |
35 | | -unmodeled objectives. By producing multiple solutions, \texttt{Osier} gives |
36 | | -modelers and decision-makers the tools to meaningfully engage with public |
37 | | -stakeholders and learn their preferences, thereby attending to issues of |
38 | | -procedural and recognition justice. |
| 4 | +marginalized and vulnerable communities. To that end, this thesis develops the |
| 5 | +first multi-objective energy system optimization framework, \texttt{Osier}, to |
| 6 | +enhance the democratic engagement necessary for a just transition. Rather than |
| 7 | +making projections about the future, \texttt{Osier} accomplishes this goal by |
| 8 | +combining user-supplied energy demand data with technology-specific data (e.g., |
| 9 | +emissions, land-use, cost) and delivers a set of co-optimal energy systems |
| 10 | +(i.e., capacities for different energy generating technologies) that balance |
| 11 | +competing priorities (e.g., emissions, cost, or land-use). Further, |
| 12 | +\texttt{Osier} acknowledges structural uncertainty --- the existence of |
| 13 | +unmodeled or \textit{unmodelable} objectives --- by extending the conventional |
| 14 | +modeling-to-generate-alternatives approach into N-dimensional objective space. |
| 15 | +This approach does not promise to model the unmodelable, rather it recognizes |
| 16 | +that any presentation of ``optimal'' solutions will necessarily miss these |
| 17 | +unmodelable priorities and that interesting solutions may be contained in |
| 18 | +models sub-optimal space. |
39 | 19 |
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40 | 20 | This thesis verified \texttt{Osier}'s suitability for energy modeling problems |
41 | | -with several \textit{in silico} experiments. The first set of experiments demonstrate that |
42 | | -\texttt{Osier} produces results that are internally consistent within its suite |
43 | | -of available methods. The next set of experiments compare \texttt{Osier} to a |
44 | | -more mature ESOM, \texttt{Temoa}, to verify that \texttt{Osier} produces results |
45 | | -consistent with known methods. The results for a least-cost optimization with |
46 | | -\texttt{Osier} and \texttt{Temoa} show strong agreement, with 0.5\% of each |
47 | | -other. In addition to benchmarking exercises, this thesis applies \texttt{Osier} |
48 | | -to two timely examples. The first uses \texttt{Osier} to reanalyze a set of |
49 | | -nuclear fuel cycle options through the lens of Pareto optimality. The second |
50 | | -shows how \texttt{Osier} optimizes a novel objective, |
51 | | -energy-return-on-investment, for a hypothetical data center. Finally, this |
52 | | -thesis validates earlier claims of \texttt{Osier}'s usefulness for energy |
53 | | -planning through a qualitative study of municipal and state-level energy |
54 | | -planners in Illinois. The results of thirteen expert interviews demonstrate |
55 | | -enthusiasm for a new tool that can optimize objectives beyond cost. However, |
56 | | -this study surfaced structural barriers to ESOM usage at the municipal level |
57 | | -which must be addressed before ESOMs, like \texttt{Osier}, can be adopted. |
58 | | -Lastly, I recommend that the state of Illinois develop a participatory process |
59 | | -for its energy modeling exercises. |
| 21 | +with several \textit{in silico} experiments. The first set of experiments |
| 22 | +establish \texttt{Osier}'s superiority at exploring decision space over the |
| 23 | +mature \texttt{Temoa} framework. A second set of experiments demonstrates |
| 24 | +\texttt{Osier} on relevant problems, such as deciding among many nuclear fuel |
| 25 | +cycle options. Finally, this thesis presents the results of thirteen expert |
| 26 | +interviews which support \texttt{Osier}'s utility for facilitating democratic |
| 27 | +engagement between decision makers and their constituents, thereby attending |
| 28 | +to issues related to procedural and recognition justice. |
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