Impact of electrified bus transport on the electricity system of Gothenburg - Can electric buses provide a service to the electricity system?
Typ
Examensarbete för masterexamen
Program
Sustainable energy systems (MPSES), MSc
Publicerad
2020
Författare
Erlandsson, Rasmus
Hodel, Henrik
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The electrification of public bus transport is regarded as an important step in decarbonising
metropolitan areas, yet little is known about its effects on the energy system
of cities. Assessments in previous research do not explicitly account for the interconnection
between electrified public bus transport and the energy system. This
thesis studies how battery electric buses (BEBs) and the city energy system affect
each other. To study electric buses in this context their driving and corresponding
charging demand must be understood. This thesis aims to understand the impact of
electrified bus transport on the energy system of Gothenburg, Sweden. A three-part
method is employed. First, a model creates a network of electrified inner-city buses
in Gothenburg and determines their time-resolved electricity demand for charging.
Second, the charging of buses is matched to an electricity cost profile, and charging
is delayed such as to minimise electricity costs for charging while fulfilling all transport
demand in the network. Third, the electricity demand of the BEBs is added
to a cost-minimising linear optimisation model of a city energy system. It models
dispatch and investments in the energy system in a scenario with net zero CO2 emissions
from heat and electricity generation in the city, and limitations in electricity
import capacity. In the energy system model, the charging of the buses is delayed
such as to reduce the total city energy system cost. The findings suggest that, although
peaks in electricity demand of buses and the city overlap in time, BEBs have
negligible impact on composition and operation of the energy system. However, benefits
can be derived from delaying charging of buses to low electricity cost events,
reducing the buses’ charging cost and the afternoon peak in the BEBs’ electricity
demand. The findings also show a synergy between the fast charging bus network
and the generation from photovoltaic solar power, where a part of the demand from
the charging of buses during the day can be satisfied by generation within the city.
Beskrivning
Ämne/nyckelord
electric buses , electrification , smart cities , Gothenburg , public transport , charging optimisation , renewable energy , electricity demand