TITLE:
Model-Based Quantification of Load Shift Potentials and Optimized Charging of Electric Vehicles
AUTHORS:
Tobias Hahn, Martin Schönfelder, Patrick Jochem, Vincent Heuveline, Wolf Fichtner
KEYWORDS:
Electric Mobility; Load Shifting; Charging Management; Optimization
JOURNAL NAME:
Smart Grid and Renewable Energy,
Vol.4 No.5,
August
19,
2013
ABSTRACT:
Managing the charging
process of a large number of electric vehicles to decrease the pressure on the
local electricity grid is of high interest to the utilities. Using efficient
mathematical optimization techniques, the charging behavior of electric
vehicles shall be optimally controlled taking into account network, vehicle,
and customer requirements. We developed an efficient algorithm for calculating load shift potentials
defined as the range of all charging curves meeting the customer’s requirements
and respecting all individual charging and discharging constraints over time.
In addition, we formulated a mixed integer linear program (MIP) applying
semi-continuous variables to find cost-optimal load curves for every vehicle
participating in a load shift. This problem can be solved by e.g.
branch-and-bound algorithms. Results of two scenarios of Germany in 2015 and 2030 based on mobility
studies show that the load shifting potential of EV is significant and
contribute to a necessary relaxation of the future grid. The maximum charging
and discharging power and the average battery capacity are crucial to the
overall load shift potential.