Introduction.

• Author: von Hirschhausen, Christian

1. THE TOPIC

   In times of growing environmental and climate concerns and increasingly cross-national energy markets, issues surrounding the coordination of infrastructure development have become more important than ever before. Today, the idea of "welfare optimization" that was one of the main objectives of traditional infrastructure policy is no longer the sole point of reference. When it comes to planning and implementing cross-border coordination, many "seams issues" arise, including the optimal scope of integration into single market zones, the sharing of costs and benefits, or the concrete steps toward achieving cross-border agreements. Cross-border coordination refers both to physical transportation infrastructure (electricity transmission, natural gas, C[O.sub.2] pipelines) and to supply infrastructure, and involves questions of generation adequacy, natural gas and electricity storage, etc. The issue is of particular importance in the search for sustainable energy security, where efforts to achieve decarbonization targets must go hand in hand with an affordable and secure energy supply.

   The objective of this Special Issue, "Sustainable Infrastructure Development and Cross-border Coordination," is to contribute original literature to this important ongoing debate, in particular on the role of infrastructure development in the cross-country context, and extending to the regional and even continental level. Our hypothesis is that to address the specific challenges that arise in coordinating infrastructure policies, rigorous modeling and institutional analyses of the surrounding regulations are required to fully understand the situation and to draw sound and meaningful policy conclusions. The papers in this Special Issue share the conviction that infrastructure development is an important element of any low-carbon strategy, but that it is not a panacea to all the problems and issues that arise on the path toward a sustainable, secure, and affordable energy future.

2. FOCUS ON EUROPE AND ITS NEIGHBORS

   While most of the challenges addressed in this Special Issue are relevant throughout the world, the papers of this Special Issue all apply their models to the specific context of Europe and its neighboring regions. Like other national and international bodies, the European Union (EU) has set concrete goals of cutting greenhouse gas emissions: the objective is a reduction by at least 40% by 2030, and towards 80-95% by 2050 (basis: 1990). In addition, the EU aims to increase the share of renewable energy by at least 27% and improve energy efficiency by at least 27% by 2030.

   Coordination is a major challenge for infrastructure...