Dear Colleagues,

Human society has been under a continuous energy transition due to various drivers. Historical transition, mainly from wood-based energy sources to petroleum products, has been driven by the availability of more efficient fuels and conversion technologies. However, with time, an increasing understanding of the impact of historical transition on planetary systems has initiated the current transition toward a clean energy future. This transition could certainly address the global warming effect of the present energy system, which came about primarily due to our dependence on fossil fuels. While the trend to abolish fossil fuel consumption, which is also unsustainable due to the consumption of finite resources, is very good news, it is important to evaluate the system we are transitioning to from a broader perspective. The success of the ongoing energy transition will depend on new energy technologies that work in tandem with new consumption patterns that result due to a more responsive society. The backbone of new energy technologies is the use of unconventional sources, such as wind and solar, and efficient and scalable storage technologies such as batteries. As more of these technologies move toward commercialization, exploitation of new minerals, including scarce ones, is expected to increase. At the same time, the diffuse nature of new sources often becomes a subject of debate as to their effectiveness in generating enough net energy to support economic development. The consumption pattern should also be price-responsive, which to some extent may depend on the weather conditions and real demand patterns.

This paradigm shift brings new research questions under the overall theme of Sustainability of Energy Transitions. Some of these questions are related to:

• Suitability of the conventional energy sustainability criteria to guide the implementation of these new shift in terms of long-term societal sustainability.

Will the increased dependence on new finite mineral resources emerge as a source of concern in the long term or maybe even limit the scale of transition in some way? Will the new energy system be able to supply enough energy to the society in the long run? Is there any risk that the new transition will somehow lead to new forms of cost volatility?

• Identifying relevant planetary boundaries as guiding constraints.

Historically, climate change had been the central criterion relevant to planetary stability that was shaping the transition direction. With the new shift to zero carbon or carbon-neutral electricity supply and electrification of other energy services such as transport, there will be an opportunity to address energy-related climate change challenges effectively. This focus on one challenge at a time, however, misses the need for safeguarding from the encroachment of other planetary boundaries. What are the boundary conditions to be considered during energy transition? Will other environmental factors emerge as a source of concern?

• Entry points for technical and policy intervention.

Do we have a clear understanding of energy system level or sector level or technology level sustainability risk? What solution can be helpful to overcome those challenges at each level? What are the policies and regulatory approaches required to enforce long-term sustainability of energy transition at national and international level?

Original research or review papers dealing with the foregoing questions that focus on various aspects of sustainability of energy transition but not limited to the following are welcome:

• Energy system or sector or technology level sustainability criteria;
• Modeling and methodological aspects relevant to identifying sustainability risk to energy transition;
• National and international policy analysis;
• Analysis of system, technology or sector level sustainability risk during energy transition;
• Analysis of experiences in implementing sustainability-oriented transitions that occurred at different scales;
• Lessons from maintaining broader sustainability goals during energy transition and tools to mitigate sustainability risks;
• Analysis of frameworks for measuring sustainability of future energy systems;
• Development and use of first order principles such as planetary boundaries in energy transitions.

Dr. Solomon Abebe Asfaw
Assoc. Prof. Dr. Getachew Assefa
Guest Editors

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• sustainable energy transition
• energy sustainability measurements
• planetary boundaries
• sustainable transition policy
• sustainable transition regulation
• biophysical limits to energy transition
• net energy return
• material requirements
• sustainable consumption
• resource depletion
• energy storage
• renewable energy
• life cycle thinking