South Africa must consider charging strategies before investing in EVs <www.engineeringnews.co.za/article/south-africa-must-consider-charging-strategies-before-investing-in-evs-2018-11-14>
14TH NOVEMBER 2018
BY: MARLENY ARNOLDI <www.engineeringnews.co.za/author.php?u_id=1184> CREAMER MEDIA ONLINE WRITER
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South Africa needs to develop controlled charging strategies before it embarks on large-scale investment in electric vehicles (EVs), Council for Scientific and Industrial Research research engineer *Paseka Mabina* said during the South African Energy Efficiency Confederation conference, on Wednesday.
He discussed the need for demand response programmes when a number of EVs are entering the road network. ADVERTISEMENT <www.engineeringnews.co.za/adcentre/rv/en/www/delivery/ck.php?oaparams=2__bannerid=2810__zoneid=420__OXLCA=1__cb=b51dc7fb23__oadest=http%3A%2F%2Fwww.jch.co.za%2F>
EVs are considered to be one of the technologies that will enable the Department of Transport to reach its target of reducing greenhouse-gas (GHG) emissions in the transport sector.
The transport sector contributes about 10.8% of South Africa’s GHG emissions, of which 91.2% comes from road transport. ADVERTISEMENT <www.engineeringnews.co.za/adcentre/rv/en/www/delivery/ck.php?oaparams=2__bannerid=2350__zoneid=647__OXLCA=1__cb=b8646cc9a5__oadest=https%3A%2F%2Fpips.seifsa.co.za>
Mabina noted that the South African government predicts that the country will have more than 2.9-million EVs on the road by 2050, which is about 25% of total registered private vehicles in the country.
However, he pointed out that, with a high penetration of EVs in a distribution system, it may bring negative impacts on the power system’s operation and control and, therefore, requires demand response strategies.
The average EV charges between eight and ten hours, using 3.8 kW chargers, and the charging duration typically falls in the load peak demands of the grid, since charging typically occurs after 17:00, which puts increased pressure on the grid and may drive up electricity tariffs.
Mabina said there is a need to accurately model the impact of EV charging on the demand profile using accurate data. He is currently doing research on the impact of uncontrolled EV charging load on the electricity distribution network.
His research so far has found that about 355 000 commuters use private vehicles to travel to work within the Ekurhuleni metro, which, should 25% of them switch to EVs, would put pressure on the power distribution system between 17:00 and 20:00.
Using Miniflex tariffs, he predicted that it would cost R1.1-million to charge 355 000 EVs in a day in the winter, should all the commuters switch to EVs. However, when shifting flexible loads such as EV charging to off-peak hours, the tariff can be reduced by 20%, and cost R619 487 to charge 355 000 EVs in a day in winter, under controlled charging conditions.
The reduced electricity tariff, or at least limiting the increase of electricity tariffs, should motivate the commuter to plan charging times in off-peak hours, said Mabina, adding that, to accommodate off-peak charging, government should consider putting up charging infrastructure at places of work or public places of interest, to enable off-peak charging.