City’s Professor of Energy Systems, Professor Keith Pullen, says that while the COVID-19 crisis has seen a reduction in the amount of toxic emissions around the capital, zero-carbon flywheel technology could resolve issues around the powering of electric car vehicles.

By Mr John Stevenson (Senior Communications Officer), Published (Updated )

Recent research suggests that as a result of the coronavirus lockdown, the emissions of toxic fumes from traffic in and around London has fallen to levels not seen for more that 70 years.

While it only speaks to emissions from vehicles and does not factor in other emissions such as wood-burning fires and central heating, the fall in noxious fumes and other harmful fossil fuel wastes points positively toward a zero-carbon future.

Efficient powering

In recent years, electric vehicles have become more available from various manufacturers and their costs are reducing to a “tipping point”, where it has become cheaper to use an electric vehicle as a fossil-fuelled equivalent. Although the purchase price of an electric car is higher, running costs are considerably less including much reduced service and maintenance costs.

All of that said, City, University of London’s Professor of Energy Systems, Professor Keith Pullen says, while the current crisis “gives a good sense of a zero-carbon future”, the real issue, with electric cars is how to power them more efficiently.

"A Kia Niro, for instance, does 280 miles on its 60kWh battery. However, to recharge at home on a 13 amp plug, it will take 29 hrs which translates into 10 miles of range for every hour of the car being charged. With a 7kW “fast” charger, these numbers are 9hrs for a full charge and 31 miles charge per hour on the charger. This is satisfactory if one is commuting around London, but for a longer journey it would be difficult. The answer is super and ultra-chargers. What is required is power on the magnitude of 100kW to charge the Niro in 38 mins. This is manageable if one is driving from London to Scotland and since you are likely to need to stop anyway before the battery is flat for food and a break, this would not be a problem on a motorway."

In the instance above, it is possible that the National Grid can provide fast charging stations fed with new multi MW cables. However, what happens when you are in rural East Anglia or Cornwall and you start to getting short of range? The problem is one of having the rural filling station provide that high level of power, without the National Grid spending millions of pounds on cables.

The answer lies in energy storage in a stationary flywheel based on technology developed by City University of London and Dynamic Boosting Systems.

According to Professor Pullen, this device “charges up slowly using the power available and when the driver connects it to their vehicle, it discharges very quickly. It behaves like a battery but the difference is that it will last 25 years without maintenance and repeat the charge and discharge a million times without wearing out. It will also be cheaper for the 100kW power required, whereas a battery capable of this power must be oversized and would need its cells replacing regularly.”

“Highways England are now funding the development of such a flywheel since it will save them a considerable amount of money as compared to either upgrading the grid or using batteries as storage.”