Electric vehicle charging trends

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Over the next five years, it is predicted that a total of eight million drivers in the UK will switch to hybrid and electric vehicles (HEVs) according to CompareTheMarket, driving demand for robust charging infrastructure. Here, Steve Hughes, managing director of transport power quality specialist REO UK, explores how the industry is shaping up for the 2020s.

EVs have proven themselves to be one of the top technological success stories of the early 21st century so far. In 2013, a mere 3,500 EVs were registered in the UK. By the close of the decade, this number had risen to approximately 255,000.

There are several factors steering this change. For automotive manufacturers, it’s becoming cheaper to manufacture EVs due to reduced component costs, substantial developments in battery technology and wider availability of large-volume manufacturing for parts such as powertrains. According to BloombergNEF, the accelerating rate of these changes will make EVs cheaper up front than combustion vehicles by as soon as 2022.

Then of course there are the environmental factors, in terms of air pollution and carbon emissions. EVs are widely seen to be cleaner alternatives to conventional vehicles due to the substantial difference in carbon emissions from use, with EVs generating only 42 % of the carbon emissions of a conventional vehicle.

Although EV manufacturing has attracted criticism from detractors for producing more carbon emissions than their gasoline-powered counterparts — 15 % according to a report by The Union of Concerned Scientists — these differences disappear when EVs are in operation.

Charging: faster but longer
The growing adoption of EVs is an undeniable win for environmentalists, but it is something of a double-edged sword for energy systems operators and electrical experts in 2020.

EV charging points are split into three main categories: slow, fast and rapid. Slow chargers, which typically are rated up to 3kW, are best suited for home charging as they can take 6–12 hours to fully recharge. Fast charging units are rated either 7kW or 22kW depending on whether they are single- or three-phase. Rapid charging, as the name implies, is the fastest. Units are generally rated 43kW for alternating current (AC) units or 50kW and above for direct current (DC) chargers.

Understandably, users want the fastest charging experience possible. It’s for this reason that many automotive manufacturers are investing heavily in developing faster charging infrastructure, such as Porsche’s electric pit stop, which promises to charge EV batteries in as little as 20 minutes.

This trend for faster charging points comes as no surprise. It’s very possible that slow charging points will largely disappear over the next few years in favor of 7kW units. This will likely be a slow process as several EV models are only now moving to onboard chargers capable of effectively using 7kW. Latest models of the Nissan Leaf, for example, have onboard chargers with a capacity of 6.6kW — almost able to make full use of the 7kW capacity of a fast point.

Grid strain
If we imagine that hundreds of thousands of electric vehicles plug in to charge at units rated between 7kW and 43kW, it becomes apparent that grid infrastructure must be robust to handle the demand.

However, it becomes more complicated when we account for the rectification that must take place to convert the AC power of many charging points to the DC required for EV batteries. This process introduces harmonic currents into the mains AC signal that, if left untreated, cause higher losses, signal interference and accelerated electrical component wear — none of which are ideal for any connected devices, let alone charging EVs.

This is arguably the biggest challenge facing the adoption of EVs and the growing usage of EV charging infrastructure. Unless these harmonic currents are accounted for and mitigated, the electrical grid will face a harmfully noisy electrical signal on top of sudden surges in demand.

Fortunately, electrical contractors can play a crucial role in minimizing the risk by ensuring that any EV charging projects include suitable harmonic filtration components in the surrounding infrastructure. For example, installing one of REO UK’s mains line filters or harmonic filters ensures that harmful currents are attenuated and filtered out to avoid damaging the integrity of the mains power.

The inclusion of filtering components seems like a common sense solution, yet it remains one that can make a significant difference in overcoming one of the fundamental challenges in EV adoption. In fact, we believe that the consideration of such harmonic mitigation strategies at a grid level will be a key trend in EV infrastructure over the coming years.

If we are to see eight million drivers make the jump to EVs in the next five years, we must begin to reinforce our infrastructure now to cope with demand. This year will be in ensuring charging infrastructure is up scratch to meet user expectations, both in terms of charging speed and overall system reliability.

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