From eandt.theiet.org: With the uptake of electric vehicles steadily increasing, grid operators have to face the challenge of making the power networks plug-in car ready before too many drivers choose to go green.
Since 2006, about 8,500 fully electric vehicles have been registered in the UK together with 125,270 hybrid cars, making up less than a half a per cent of all cars on British roads.
However, according to available data, the number of drivers opting for a vehicle with extremely low emissions is growing every year and with the widespread governmental incentives in place, the trend could be expected to continue. Between July and September 2013, 1,210 new ultra-low emission vehicles were registered in the UK for the first time – about 23 per cent more than during the same period one year earlier.
Alongside the electric vehicle fleet the network of electric vehicle chargers is expanding, which at the end of 2013 consisted of nearly 9,000 publicly funded charging points across the UK.
These chargers have been largely lying idle most of the time so far, but experts have already warned that unless users are strictly disciplined to charge their vehicles overnight, the electric vehicle revolution could put a strain on the electric power grid, potentially causing local power outages during peak demand hours.
“So far, the number of electric vehicles on the roads is really negligible, but it is expected to increase,” says Michael Clark, programme director of the Low Carbon London project at UK Power Networks. “Once we get to a double-figure percentage market share of electric vehicles, they may become a problem. Electric vehicles tend to be connected to low voltage networks and it is this impact that we are investigating before it becomes a constraint on distribution networks.”
Going green a challenge
Getting the grid plug-in car ready is an increasingly pressing issue. The UK government has committed to source ten per cent of UK transport energy from renewables by 2020 and estimates suggest that by 2030 electric and hybrid vehicles could make up to 25 per cent of all cars on the UK roads. By that time, half of the transformers closest to homes and business might be in a need of an urgent overhaul – unless a cheaper, possibly software-based solution is found.
Together with Imperial College London, electric vehicle charging infrastructure developer POD Point and Scottish company Smarter Grid Solutions, UK Power Networks launched a pilot study evaluating the possibility of using a smart grid management system to deal with the excessive load from electric vehicle charging points.
“To deal with the excessive demand for electricity, you can either lay new cables and re-equip sub-stations with extra switches – which obviously costs a lot of money and is rather disruptive – or you can try to manage all those charging points through a smart grid management system,” says Alan Gooding, Smarter Grid Solutions' Commercial Director and Co-Founder.
The study, part of UK Power Networks’ Low Carbon London project, involves 50 charging stations in central London – an area with generally high power consumption.
“What we have installed is software that monitors in real time, on the level of sub-seconds, the electricity flow through parts of the London network and when the electricity network becomes congested or under stress, the software asks the electricity charging stations to reduce their consumption,” explains Gooding.
Smarter Grid Solution’s Active Network Management system has previously been used to integrate larger local energy generation systems, such as solar installations, wind turbines and combined heat and power (CHP) generation facilities, into congested electricity networks. The smart network management system consists of five platforms managing data exchange between the system and the grid, performing calculations and implementing measures to reduce the load on the grid in real time.
“We are doing all this in conjunction with the electric vehicle charging infrastructure so that any of those vehicles that still require a charge gets the charge. It’s kind of an intelligent system.”
Not cutting drivers short
Gooding says the system has been designed to disconnect the charging points from the grid for such short periods of time that the drivers shouldn’t notice any difference in the total charging time of their vehicles.
“The system has been designed to have no noticeable impact on the users of the charging stations. It takes into account when people are expecting to come back to their car and be charged,” Gooding explains, adding that the system is fully automated, not requiring any additional operational overhead.
The trial has been underway since December 2013 and UK Power Networks expect to have first results available by the end of 2014.
“It’s only a trial. We have to wait for the results to see whether it’s actually working the way we expect and decide whether it’s something a network operator should be doing,” says Clark.
As part of the Low Carbon London project, UK Power Networks has been testing various approaches to make the grid ready for the decarbonisation revolution. Experts have warned that not only the growing number of electric vehicles but also the increasing share of wind and solar installations with their unpredictable and fluctuating energy generation present the biggest challenge the UK power grid has faced since its construction in the 1930s.
The future grid
In the framework of the £28m Low Carbon London project, running from January 2011 to December 2014, UK Power Networks has investigated various low carbon technologies that could in the future change the face of London’s power grid.
“One of the approaches we have been testing to reduce peak demand loads is local energy generation for, for example, big office buildings – we have been testing novel commercial arrangements which provide a contracted service for buildings to ‘turn down’ their demand altering the use of systems such as heating and cooling,” says Clark, who believes the way forward is not only in the smarter grid but also in smarter or better informed users.
“We have already trialled this approach, providing users with incentives similar to mobile phone operators offering considerably cheaper off-peak tariffs and it has been working very well,” he says.
It’s quite likely electric car users will be intrigued by such incentives allowing them to fill the ‘electrical tanks’ of their cars fully up and pay just a couple of pounds. And if not, the smart grid management system will prevent those environmentally friendly vehicles from wreaking havoc with the wider city grid.