Strategic environmental assessment (SEA) and sustainability are inextricably linked. SEA can be used to assess the sustainability impacts of plan, program and policy (PPP) initiatives, inform decision-making with regard to sustainability issues and promote the trickle down of sustainability principles to project level assessment, among others. However, in terms of energy sector practice in particular, SEA application is neither well applied nor understood, there has been insufficient evidence of the operationalization of sustainability in SEA and little research showing how SEA might provide a systematic framework for the integration of sustainability principles. As a result, this thesis examines the relationship between SEA and sustainability, with the goal of understanding how sustainability principles and criteria can be integrated and operationalized in the development of energy futures. The thesis chapters are manuscript based. The first manuscript presents a literature review of ten years of academic research examining how SEA facilitates the integration of sustainability in PPP development decision making, while the second and third manuscripts focus on a ‘state of practice’ examination of SEA application and sustainability integration in international electricity sector case practice. The fourth manuscript applies a structured SEA framework that operationalizes sustainability principles using an expert-based assessment of alternative future scenarios for electricity development in Saskatchewan, along with an examination of implications for both electricity sector practice and SEA methodology. Finally, the conclusion discusses the major findings from the four manuscripts and identifies challenges for the operationalization of sustainability, the adoption of good-practice SEA elements in practice and makes recommendations for future SEA guidance and academic research.

Overall, the lack of operationalization of sustainability in energy sector SEA suggests the need for improved SEA methodology and guidance that describes the scope of and approaches to sustainability in SEA and outlines how to effectively incorporate sustainability in SEA practice. In order for SEA to deliver on its sustainability mandate, impact assessment methodologies that allow for clarification of both the concept of sustainability and the uncertainty surrounding higher level policy, plan and program (PPP) decision-making need to be developed and more widely adopted. Lessons learned from practice that describe the appropriate use of both quantitative and qualitative methodologies also need to be better disseminated and shared amongst the SEA research and practitioner community. However, results from this research also illustrate that there is still inconsistent application of SEA processes, which likely stems from uncertainty and confusion on behalf of practitioners and decision-makers as to what the role and purpose of SEA is in PPP development. More case-practice evidence of SEA application is needed that demonstrates the purpose and benefits of SEA for sustainability in a variety of decision-making contexts. Evidence from this research also shows that tiering, both upward to higher PPP levels and downward to the project level, is occurring in some electricity sector SEAs. That SEA outcomes are potentially tiering upward to influence the development of legislation is a finding that counters the often-cited notion that tiering in SEA is idealistic. This research indicates the need for additional focus on institutional arrangements that allow for SEA application to effectively inform and influence PPP decision-making in support of sustainability. The need for SEA as a higher order assessment process to capture regional and strategic impacts is becoming increasingly important in light of current federal legislation that eliminates environmental impact assessment requirements for many small-scale projects. However, although SEA emerged, in part, to inform and direct decisions made at the project level, the link between SEA, sustainability and operational decisions still remains elusive in practice.