Researchers tackle smart grid challenges head-on
KU Leuven researchers are exploring smart grid routes to keep existing infrastructures from overloading as electrical cars become more popular in Flanders
Local methods for first adopters
A handful of researchers at the University of Leuven (KU Leuven) may end this standoff with their new findings on the grid infrastructures needed in an electric-car friendly Flanders.
The university is investigating promising and cost-effective ways of protecting electrical grids as the numbers of vehicles charging from them increases as part of a research effort under the umbrella of the sustainable energy research institute EnergyVille.
Leuven researcher Niels Leemput explains that their task is to create a “grid-integrated charging infrastructure” for electric vehicles. Smart charging would keep the grid within its operational boundaries. It is designed to measure the status of the grid and the needs of the vehicles and, if necessary, deliver a slower charge to the cars, protecting the grid from overloading.
Leemput is working on the infrastructure for low-voltage grids, for roughly 100 to 250 households, while researcher Juan Van Roy is exploring the benefits of smart grid integrated buildings, such as apartment and office blocks.
“So far, a lot of research has investigated very complex and advanced charging strategies, which will be necessary in the long-term,” says Leemput, “but short- and mid-term low-tech solutions have been ignored.”
“You need local methods for the first users of electric vehicles because a centralised system would be too expensive for a few cars,” continues Van Roy, pointing out that not all areas are likely to adopt electric cars at the same rate. Wealthier neighbourhoods, for instance, are likely to have more electric cars sooner.
Plugging in at the office
“An electric car will consume the same amount of energy as a household,” Leemput says, adding that grid operators will need to adapt accordingly. They could do this by installing additional cables, but this typically costs tens of thousands of euros for a cable that supplies 20 to 40 households.
When you increase the opportunities for charging, you decrease the impact at home
It is possible, however, to implement adaptations using software in the vehicle, as the hardware required is already in place. This would result in lower costs and fewer roads being dug up.
There are also major benefits to charging electric cars at the office. “When you increase the opportunities for charging, you decrease the impact at home,” notes Van Roy, thereby spreading the load. Though this may increase the impact on the grid near the office, this can be offset by use of photovoltaic installations or solar arrays. Leemput says it is possible to “use the rooftop space that office blocks have to install solar panels and use them to charge vehicles on their parking lots”.
Impact on the grid can also be reduced by controlling the amount of power used to charge each car. Van Roy says that you could use “delaying”, or charge different cars at different times. “But this could leave drivers without any power in case of an unexpected journey,” he says.
It’s better, he continues, to charge continuously with a lower power rate. “This also reduces the impact on the grid, is better for the battery life of the car and can leave you with some energy in an emergency.”
The only downside is that it would take longer, but this is made up for in a number of ways. First, most cars in Flanders have long standby times, as they are mainly used to travel between home and work. They also only drive about 40 kilometres per day on average, so the energy needs are relatively low.
Second, there are a number of incentives to convince, but not force, drivers into slow charging, including the aforementioned battery life but also a cheaper electricity tariff when participating in smart vehicle charging.
Avoiding blackouts
Leemput stresses the importance of “simple and robust strategies”. He says that many people compare electricity grid problems to IT hiccups, but you can resend lost data, he points out “which you cannot do with energy.” The reliability of a power system needs to be much higher than that of IT solutions to avoid blackouts.
If you have simple back-up mechanisms, you can avoid a blackout
“In the future, once the centralised system is installed, local systems will still work as a backup in case the larger network fails,” Van Roy says.
Because the larger networks would have to be connected to the internet to run automatically, a cyber-attack could cause huge problems. “But if you have these simple mechanisms as a backup,” says Leemput, “you can still avoid a blackout. Local smart grid controls are simple, robust and offline”.
The smart charging strategies offer a safe and possibly cost-effective solution to a problem that is close at hand and has been largely overlooked. Many of the methods used have been tried and tested before in other applications, and robust load control techniques are already used in parts of the US to regulate the supply of power to air conditioning units at peak moments. This all makes widespread use of electric vehicles a far more plausible possibility than before.
