southampton

Published:: 9 January 2019

Worldwide numbers of electric cars and trucks are set to rise from 1.7 million to 5.3 million by 2020. In the UK, the anticipated pressure that charging these vehicles will cause to the National Grid’s energy supply is a vital challenge that needs to be overcome. University of Southampton engineers and computer scientists have designed a new pricing system, based on online auction platforms, to make charging electric vehicles more effective.

Five things you might not know about green electrics:

The UK government want nearly every vehicle in the country to be zero emission by 2050
On average it costs £2 to £3 to fully charge an electric car, giving a typical range of 80 miles
There are 57,567 charging points in Britain, roughly double the number of electric cars registered on the road
A consortium including Land Rover and Nissan are exploring the use of F1 technology to make plug-in cars drive 25% further
Highways England have spent £200,000 investigating electric motorways, which can charge electric cars as they drive on them

Optimised charging

The researchers have devised a system where electric vehicle owners use computerised agents to bid for the energy to charge their vehicles, and to organise time slots when a vehicle is available for charging.

Plug-in electric vehicles are expected to place a considerable strain on local electricity distribution networks. If many vehicles charge simultaneously, they may overload the local distribution network; so their charging needs to be carefully scheduled.

Dr Enrico Gerding, who is one of the academics leading this research, and his colleagues have designed a system that allows users to enter their details, including at what point they will need to use their car, and how far they are planning to drive. This scheduling process not only takes pressure away from the grid by charging vehicles in a logical ‘order’, but it also saves those users money who can be more flexible with their charging allocation.

Dr Sebastian Stein , who is undertaking this research alongside Enrico, says: “Users can input a time when they plan to depart, and the system can reprice their usage if they depart earlier. We want people who actually need their cars to have what they need, so it is important that people are truthful about their requirements.”

The electricity infrastructure in the UK is not currently built to support the number of electric vehicles there are expected to be in use by 2020. “The local transformers, which step down high voltage to low voltage, have been built for the electricity demands of a normal household, and they are already frequently at the top of their capacity. An electric vehicle draws at least the same power again as a normal household, so it doubles the energy consumption, which could be a huge problem,” explains Enrico.

Strong incentives

The proposed system that the team is developing incentivises people to be honest and flexible about their transport requirements. For example, for people who arrive home from work and don’t plan to use their car again until the morning, the system can charge the vehicle at an off-peak time, and the user will pay less than if they need to charge their car at a peak time.

“For us, it is all about incentivising the scheduling for the user,” comments Sebastian. “The way we do this is by lowering the charging costs the more flexible you can be. What’s more, the system should be very straightforward to use. All the user needs to do is tell the system what time they need their car, and everything else will be done automatically.” The team is expanding on this idea by looking at intelligent software components for this mechanism, which can detect the usual usage levels of individual cars, and can participate in the auction process on the owner’s behalf.

Enrico and Sebastian are currently collaborating with a leading international car manufacturer to address some of the challenges of transitioning their research from theory into practice. Enrico says: “The key problem for us at the moment is establishing whether we need a complex system that offers more flexibility to the user, or a simpler system that offers fewer flexible options for their charging schedule. Our priority, however, is to ensure that the day-to-day commercial and personal users of the system can understand it.” They have developed the website www.bid2charge.com, which turns the charging mechanisms into a game to test how users will interact with them.

Recently, Enrico and Sebastian have also started looking at a vehicle-to-grid (V2G) setting, where electric vehicles can give back power to the grid to support it at times of high demand and users can make a profit from selling this energy.

Storing power

Professor of Power Electronics Machines and Drives, Suleiman Sharkh and Professor of Energy Technology, Andrew Cruden , have completed a three-year project on V2G, funded by the Engineering and Physical Sciences Research Council (EPSRC).

Two Southampton alumni provided the equipment needed to undertake this research. REAP systems, founded by Dr Dennis Doerffel, designed, manufactured and installed the Energy Storage Solution based on Yuasa cell technology, and the bidirectional grid-connected charger is designed and built by Dr Mohammad Abusara from HiT Power.

Using this charger, Suleiman and Andrew have been able to test the feasibility of charging and discharging batteries, and model ways to make the process more energy efficient, using smart grids with internet technology to control the system. They undertook this work in collaboration with colleagues at the universities of Sheffield, Warwick, Liverpool and Strathclyde in the UK and Huazhong and Tsinghua in China, in addition to China Electric Power Research Institute (CEPRI).

PhD students from the University of Southampton’s Centre for Doctoral Training in Energy Storage and its Applications , supervised by Suleiman and Andrew, also had an important role in developing V2G optimal dispatch systems for alleviation of electricity network overload, while maximising the use of available renewable energy.

As electric vehicles become increasingly popular, it should be possible to link their energy storage capacity to the national grid. This should help relieve the grid and even out the peaks and troughs of power generation and storage during the times in the day when they are not being used.

Suleiman is currently collaborating with a local startup company set up by a University of Southampton graduate, Dr YewBie Cheng, and supported by Future Worlds to incorporate the V2G dispatch algorithms. The company has recently launched a new app, mevCharge for planning travel routes and charge stops for electric vehicles to ensure that the batteries remain charged during long journeys, which will help reduce range anxiety. mevCharge has been designed to be easy to use, and allows drivers to enter vehicle details and select the type of charging points. As well as incorporating intelligent V2G dispatch, the company plans to include charge point crowd sourcing.

Feasible solution

“We need to understand more about the practicalities of using car batteries in this way, whether the process would wear out the battery too quickly or cause too much inconvenience for the driver,” explains Suleiman. “Like us, our university partners are also involved in cutting-edge research in this area, which could transform the energy generation and transport in years to come,” he adds.

In the medium term, it is important that we are focusing resources into the development of more effective electric vehicles. “The government is paying real attention to the development of electric vehicles, as they are currently the only feasible solution to reducing carbon emissions in the transport sector,” Sebastian says. “The Committee on Climate Change, an advisory group to the government, recommends that by 2040, all new cars need to be zero-emissions vehicles. As such, we will see a huge rise in electric cars in the UK.”