Due to international commitments to reduce emissions in the shipping sector, new fuels and drivetrains are being explored. However, the potential role of batteries is often overlooked in strategic studies. We fill this gap through a broad literature study of grey and academic literature, complemented with three deep dives into Systems Engineering, Sustainable Business Models, and Transition approaches. Battery electric systems are currently the most frequently applied among alternative fuel-drivetrains, although they account for a low percentage of energy use. They are the preferred technology for zero-emission vessels. However, they mostly find application in small to medium hybrid vessels and support functions. Key drivers are regulation and policies, the increase in energy density, and the decrease in costs. Sectoral barriers include infrastructure, the capital intensity of vessels, cost-driven performance, weak governance, and international operations. Challenges for battery applications include integration in a ship's energy system, battery safety, charging, decision support on feasible applications, and establishing viable renewables-based port energy communities that integrate services to and from battery systems on berthing ships. Due to their diversity, versatility, and current application, batteries are likely to become more broadly applied on small to medium-sized vessels, and as enabling technology in hybrid applications and support functions. They thereby have the potential to influence the transition in the sector. Considering the diversity in batteries, shipping segments, and contexts, this will result in many small steps forward. Fast development requires strong policy support. Inherent uncertainty regarding fuels and drivetrains is best countered by robust decision-making in the sector, and can include battery usage.

An increasing number of studies have analysed the scope for, and the barriers to, transitions toward sustainability in the context of developing countries building on analytical perspectives from the sustainability transitions literature. This paper introduces a special issue on sustainability transitions in developing countries, which takes stock of this emerging field of research and presents new empirical research that contributes to further advancement of our understanding of the conditions in which sustainability transitions are likely to take place in developing countries and what is involved in these transformative processes. This introductory paper presents the five papers contained in the special issue. The first paper comprises a review of the existing literature on the subject, and the other four papers present new empirical research. The key findings of the papers are discussed in relation to previous research in the field specifically related to four crosscutting themes: (i) global-local linkages and external dependencies; (ii) stability and non-stability of regimes; (iii) undemocratic and non-egalitarian nature of regimes; and (iv) nurturing the development of niches versus the execution of individual projects. The introductory paper concludes by presenting a research agenda, which aims to provide promising avenues for future research on sustainability transitions in developing countries.