Review on Investment Schemes of Urban Underground Utility Tunnels in Multiple Energy Systems

As a part of multiple energy systems, the urban underground utility tunnel plays an important role in improving the utilization efficiency of urban underground space. However, single investor and difficult financing problem make the construction of urban underground utility tunnels more and more difficult. Thus, it is very important to study a reasonable and effective investment scheme for investing the utility tunnels in multiple energy systems. In this paper, a review on investment schemes of urban underground utility tunnels is presented. The basic properties and related subjects of the utility tunnels are summarized and analyzed. The investment schemes are divided into three types according to the different investment subjects: government direct investment scheme, government and companies joint investment scheme, and public-private partnerships investment scheme. Moreover, the three schemes are introduced and analyzed in detail according to the actual investment cases.