Designing an Electric Road System

Sammanfattning: Electric road systems (ERS) provide electric power to vehicles en route (dynamic charging) and can reduce the need for onboard battery capacity. This thesis sets out to examine the power demand of an ERS and the integration of energy storage in its power supply for grid load alleviation and backup power. Specifically, the analysis is based on the ongoing project to build a permanent ERS on a 21 km section of highway E20 between Hallsberg and Örebro, Sweden. Power demand is calculated as a function of hourly traffic flow during a heavily trafficked day, vehicle energy consumption over the distance and the placement of ERS segments. An energy storage system (ESS) for leveling peak power demand (peak shaving) is dimensioned as a function of power demand and some set grid power limits. It is assumed that the vehicles in need of emergency backup can be represented as a share of the traffic flow. Conclusively, the power demand varies significantly in both time and space. The peak power demand from the ERS is 15 MWh/h when all trucks are assumed to use the system and 36 MWh/h when all cars are included too. The power demand from cars has a very distinct peak during the afternoon, whereas that from trucks has a more even demand throughout the day. ESS can make the most difference when intense but short peaks are present, making it appear most suitable when cars are included as ERS users. The suggested ESS capacities for peak shaving (6-45 MWh) can also be used to sustain critical transport 1-12 days, where the number of days depends on what share of the traffic is considered critical. Finally, only vehicles driving further than the range of the onboard battery are likely to need the ERS. A sensitivity analysis is done to estimate what power demand can be expected in both the short and long term.