Large scale regional adoption of electric vehicles in Norway and the potential for using wind power as source

Abstract

Recent years attitude towards climate and CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> emissions has accelerated the sale of electric and hybrid vehicles in Norway. By the end of 2012 there were 10 000 battery electric vehicles registered. Projections indicate that Norway may surpass 200 000 chargeable vehicles by 2020, counting both battery electric vehicles and hybrid electric vehicles. This corresponds to 7 % of the total vehicle fleet. To explore the impact a large scale electric vehicle adoption will have on the power grid, simulations of an existing low voltage power system has been conducted. The load flow simulation tool Simpow was used for this purpose, and Nord-Trondelag Elektrisitetsverk provided information of the grid structure and consumer consumption data. From the supplied data, December 22 was chosen for the 24 hour simulation period, because it represents the highest energy consumption scenario. A hypothetically built wind turbine close to the residences was integrated in the system, using wind measurement data from a wind farm in Nord-Trondelag. Different scenarios with regards to electric vehicle charging were explored, investigating how sensitive the grid is to additional load under different assumption patterns, and how the wind generation can contribute to a more self-sustained power system. Symmetrical and asymmetrical distribution in relation to physical location of the additional load has been compared, and the results suggest that one cannot give an exact number of vehicles that the system can handle. This system capacity when operating with dumb charging strategies is somewhere between 4 and 22 electric vehicles, depending on where the vehicles are situated physically. In other words, the placements of the additional loads are equally decisive for the system voltage variations as the number of loads are. By applying smart charging strategies, it seems the system is able to handle a large share of electric vehicle adoption. Wind generation during December 22 is higher than the residence base consumption, resulting in 593 kWh excess energy in the system. An energy storage of a 100 kWh capacity in addition to the wind generation could cover base load if the system was to operate without grid connection. Additionally, the excess energy could potentially be used to charge electric vehicles.