The paper investigates investments in gas infrastructure considering uncertainties in European gas markets. Furthermore, the study addresses the question of whether (more) diversification provides a (better) security of supply improvement. Thus, a stochastic optimization approach is introduced. The uncertainties focus on 2030 and 2045 in three dimensions, namely the Ukraine gas transit, future LNG prices, and the expected gas demand. Considering three diversification strategies, the model GAMAMOD-EU.sto optimizes investments in pipelines, LNG import terminals and gas storages as well as the gas dispatch. Results illustrate trade-offs between optimal gas supply and diversification strategies. Investments in pipelines to North African suppliers are made across all strategies, while the building of the Nord Stream 2 pipeline depend on the respective diversification strategy. Diversification through LNG quota changes the dispatch results significantly. Investments in storages are almost not necessary over all strategies, however, storages provide flexibility to prevent supply shortages, when diversification strategies are applied. Conclusion for policy makers regarding what is needed for preventing malinvestments and high costs in the European gas market are: an enhanced relationship between Russia and the EU and a clear vision on the role of gas in the future European energy system that reduces demand uncertainty.

考虑到欧洲天然气市场的不确定性，本文研究了对天然气基础设施的投资。此外，该研究解决了（更多）多样化是否提供（更好）供应改善安全性的问题。因此，引入了随机优化方法。不确定性集中在三个方面的2030年和2045年，即乌克兰的天然气运输，未来的液化天然气价格和预期的天然气需求。考虑到三种多样化策略，模型GAMAMOD-EU.sto优化了管道，LNG进口码头，储气库以及天然气分配方面的投资。结果说明了最佳天然气供应与多元化战略之间的权衡。涉及北非供应商的管道投资涉及所有策略，而Nord Stream 2管道的建设取决于各自的多元化策略。通过液化天然气配额的多样化极大地改变了调度结果。几乎不需要在所有策略上都对存储进行投资，但是，在采用多样化策略时，存储可以提供灵活性以防止供应短缺。就防止欧洲天然气市场上的投资错误和高成本所需要的政策制定者的结论是：俄罗斯与欧盟之间的关系得到了加强，并且对天然气在未来欧洲能源系统中的作用有了清晰的认识，从而减少了需求的不确定性。当采用多样化策略时，存储可以灵活地防止供应短缺。就防止欧洲天然气市场上的投资错误和高成本所需要的政策制定者的结论是：俄罗斯与欧盟之间的关系得到了加强，并且对天然气在未来欧洲能源系统中的作用有了清晰的认识，从而减少了需求的不确定性。当采用多样化策略时，存储可以灵活地防止供应短缺。就防止欧洲天然气市场上的投资错误和高成本所需要的政策制定者的结论是：俄罗斯与欧盟之间的关系得到了加强，并且对天然气在未来欧洲能源系统中的作用有了清晰的认识，从而减少了需求的不确定性。