Abstract

The transport system in Sweden is going through a major transition towards a fossil free transport sector. A part of this transition is to introduce electric vehicles. Many Swedish cities have already started their progress by electrifying their city buses. Uppsala aims to introduce the first electrical buses by 2021. An electric bus does not emit any emissions while driving and it will reduce the noise emissions in the city.

Currently, Region Uppsala is building a new city bus depot. The depot is planned to be ready for use by the second half of 2020. When Region Uppsala applied for a connection to the electrical grid, they got denied their desired power output. The reason for this is the capacity-shortage in the transmission grid to Uppsala. Svenska Kraftnät, who is responsible for the transmission grid, claims that the capacity-shortage will be solved around 2030. This means that the operation of the new bus depot must be adjusted to a limited power output. Given these circumstances, it is uncertain if electrical buses can be introduced in Uppsala before 2030.

The purpose of this study has been to investigate how a different number of electrical buses will affect the power demand at the new city bus depot. In addition to this, different technical solutions were investigated to examine the possibility to introduce electrical buses in a city which suffers from capacity-shortage. The results show that the limit for the power output will be exceeded by 200 kW already with 12 electrical buses.

To be able to introduce electrical buses in Uppsala, some sort of technical solution must be implemented. The technical solutions were evaluated by a life cycle cost analysis. The
cheapest solution turned out to be connecting the city bus depot with the regional bus depot. This is possible because the grid connection by the regional bus depot is greatly oversized compared to its load. However, this solution does not solve the problem with capacity-shortage and the legality of it must be analyzed further. Other solutions that were investigated was to place a local battery storage or a gas engine at the depot. None of the solutions could solve the power problem at the depot on its own. For a scenario with a large number of electrical buses, the different technical solutions must be combined.