IEEE Power & Energy Magazine - Grid Edge 2023 - 76

Key Lessons Learned
This article presented the main outcomes from one of the
largest (if not the largest) EV trials in the world, MEA. The
key lessons learned in terms of the charging habits of EV
users, how EVs impact low-voltage networks, the effectiveness
of the proposed EV management solution to increase
corresponding hosting capacity, and the potential provision
of services to the grid are summarized.
EV Charging Behavior
The MEA project recorded the charging behavior of nonmanaged
EV users in the United Kingdom for nearly two years.
Among all key outcomes presented in this article, the data
analysis demonstrated that approximately one-third of the
EVs were charged more than once per day (a unique finding
not previously explored) and that the charging behavior from
one season to another is similar. The MEA project also found
that not all EVs are charged on the same day; the results show
that, on average, there were two days each month in which
no EV was charged (from the 219 EVs involved in the MEA
project, there were two days per month, on average, in which
no EV was plugged in at all). The results of the data analysis
are expected to be used in different EV studies ranging from
customer demand to system-level management schemes.
EV Impact on Low-Voltage Networks
The MEA network studies first investigated the hosting capacity
of different low-voltage distribution networks. The probabilistic
analysis highlighted that the peak demand of the EVs
is likely to coincide with the existing evening peak. From the
perspective of DNOs, the maximum demand of households
with an EV charging in slow mode will grow, on average, to
roughly 2 kW per household (i.e., DNOs in the United Kingdom
will need to plan for 2 kW per house), double that of the
conventional demand. Studies on nine different low-voltage
networks found that, for some of them, problems start at 40%
penetration (i.e., a hosting capacity of 40%). This was mainly
due to the transformer located at the substation, followed by
thermal problems at the low-voltage feeders; only long feeders
may face voltage issues for very high EV penetration levels.
The proposed methodology to assess this hosting capacity can
be adapted by other countries in the process of deploying EVs.
EV Management Solution
The MEA project also demonstrated that deploying the EV
management solution can increase the hosting capacity of
low-voltage networks to 100% in all of the simulations and
actual trials. Although the technical impacts could be fully
mitigated since the EVs are switched off when a problem
arises, the studies showed that charging delays and battery
degradation can occur because of the repeated management
of the EV. This means that if EV management solutions are
to be truly adopted, an effective deployment should consider
the tradeoff among the benefits from the control, the capabilities
of the EV batteries, and the potential technical issues
76
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on the networks. The EV management solution tested by the
MEA project is considered practical and scalable enough to
be deployed by other DNOs.
Provision of Services
The produced EV models also allow for quantifying the
potential provision of grid services to help maintain the balance
between demand and generation. While the availability
changes from weekdays to weekends and throughout the
day, it was found that, in approximately 12 years, the average
weekday availability can be equivalent to approximately
4.5 million U.K. households. Although there is a great po -
tential for EVs to provide services, their deployment will
fully depend on the benefits that the EV customers receive.
Hence, the scale and range of these services will eventually
require understanding not only the technical challenges but
also the social, financial, and environmental ones.
The outcomes from the MEA project can help integrate
EVs into most electricity systems around the world. In the
United Kingdom, a new project called Electric Nation (www
.electricnation.org.uk) is already building on the understanding
from MEA and plans to deploy more than 500 EVs to
study different cost-effective solutions to manage networks
ranging from demand response to V2G applications. The
deployment of this project, and many others that will take
place in the next decade, demonstrates the value of EV trials
in providing outcomes that will facilitate the transition
toward the electrification of the transport sector.
For Further Reading
International Energy Agency. (2017, June). Global EV outlook
2017: Two million and counting. IEA. Paris, France. [Online].
Available: https://www.iea.org/publications/freepublications/
publication/GlobalEVOutlook2017.pdf
EA Technology. (2016, Mar.). My Electric Avenue-
Project closedown report. EA Tech. Chester, U.K. [Online].
Available: http://myelectricavenue.info/sites/default/files/
documents/Close%20down%20report.pdf
J. Quirós-Tortós, A. Navarro-Espinosa, L. F. Ochoa, and T.
Butler, " Statistical representation of EV charging: Real data
analysis and applications, " in Proc. PSCC, 2018, pp. 1-6.
J. Quirós-Tortós, L. F. Ochoa, S. W. Alnaser, and T. Butler,
" Control of EV charging points for thermal and voltage
management of LV networks, " IEEE Trans. Power Syst., vol.
31, no. 4, pp. 3028-3039, 2016.
Biographies
Jairo Quirós-Tortós is with the University of Costa Rica,
San Jose.
Luis (Nando) Ochoa is with the University of Melbourne,
Australia, and the University of Manchester, United
Kingdom.
Timothy Butler is with EA Technology, Chester, United
Kingdom.
p&e
november/december 2018
http://www.electricnation.org.uk http://www.electricnation.org.uk https://www.iea.org/publications/freepublications/publication/GlobalEVOutlook2017.pdf https://www.iea.org/publications/freepublications/publication/GlobalEVOutlook2017.pdf http://myelectricavenue.info/sites/default/files/documents/Close%20down%20report.pdf http://myelectricavenue.info/sites/default/files/documents/Close%20down%20report.pdf
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