IEEE Power & Energy Magazine - Grid Edge 2023 - 67

The electrification of transportation can bring environmental,
health, and economic benefits when coupled with a low-carbon
electricity generation portfolio.
understanding that DNOs and regulators will find useful.
Table 1 details the key aspects of the project. The corresponding
reports, findings, and key data are publicly available
on the project's website.
Understanding How People
Charge Their EVs
Understanding when and for how long EV users will charge
their vehicles is one of the most critical aspects to realistically
studying EV interactions with the grid; however, EV
data are scarce, which highlights the need for more trials
that make key data publicly available. The MEA project
recorded more than 85,000 nonmanaged charging events.
Every time an EV user charged a vehicle, the onboard
monitoring system recorded the start charging time and
the initial/final state of charge (SOC). The project used
the information from the 219 EVs involved in the project
to understand the drivers' charging habits. Although the
knowledge gained from the MEA project may be specific to
EV drivers in the United Kingdom (and similar countries),
the methodology used is generic and can be adopted by any
country or region.
One interesting finding from the MEA project is that the
variance in the charging behavior across seasons is limited,
i.e., there is no seasonality. This allows for grouping all charging
events and corresponding metrics into two categories:
weekdays and weekends. Another interesting finding is the
highly erratic charging pattern shown by EV users during
roughly the first seven days of use. This was considered to be
a familiarization phase, and the final database excluded the
events during the first week (i.e., <1% of the total charging
events). The following sections discuss, via histograms, the
project's key findings in terms of charging habits, including
the number of charging events per day, start charging time,
initial/final SOC, and percentage of EVs charging on the
same day.
Charging More Than Once Per Day?
Whether on a weekday or during the weekend, approximately
30% of EV users charged their vehicles more than
once per day, as shown in Figure 3, which also shows, however,
that the majority of EV users (70%) charged their vehicle
only once per day. This finding is unique because most
EV studies do not explore multiple charging events. Finally,
because of the low occurrence of three or more charging
events (<8%), they were considered part of the second chargnovember/december
2018
ing event. However, the study methodology can be used to
consider as many charging events as necessary.
Charging Early or at Night?
It was found that the first charge might occur any time during
the day, but the second charge was more likely to occur after
midday. Figure 4 presents the start-charging time for weekdays
separated into three periods of the day (morning peak
from 6 to 10 a.m., evening peak from 3 to 9 p.m., and the rest
of the day). The most common first charge time started at
approximately 8 a.m. (before work) or at 6 p.m. (after work);
table 1. The MEA project fact sheet.
✔ Total cost: US$13 million*
✔ Project length: three years
✔ Project website: www.myelectricavenue.info
✔ Scale
n Total number of EV users: 219 (101 technical and 118
social)
n Low-voltage networks in the technical trials: ten (nine
residential and one commercial)
✔ Infrastructure
n Measurements
* Network: Phases V and I (10-min resolution)
* EVs: start/end charging time, initial/final SOCs, start/
end trip time, and initial/final odometer
n Communications
* EV charging point  substation: PLC
✔ Project partners
n Leader: EA Technology
n DNOs:
* Scottish and Southern Energy Network (lead DNO)
* Northern Powergrid (participating DNO)
n EV supplier: Nissan
n Academia:
* The University of Manchester, United Kindgom
(technical analysis)
* De Montfort University, Leicester, United Kingdom
(socioeconomic analysis)
n Others: Fleetdrive Electric, Zero Carbon Futures, and
Ricardo
✔ Areas of study: engineering, social sciences, environment,
and economics
*All dollar values in this article are reported adopting the following
conversion rate: GBP £1 ➝ US$1.431.
ieee power & energy magazine
67
http://www.myelectricavenue.info
IEEE Power & Energy Magazine - Grid Edge 2023

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