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Smart Charging Is Better Than Dumb Charging, German EV Study Finds

For the past 15 months, Netze BW, the utility grid operator in Germany’s Baden-Württemberg region, has been studying the charging habits of electric car drivers in its service area. The data collected has been compiled to create a new report that allays many of the fears about charging lots of electric cars simultaneously.

If you read CleanTechnica on regular basis, you know fossil fuel money is being used to attack the idea of electric cars. The news is filled with reports from so-called think tanks saying EVs in general have too short a range, take too long to charge, have batteries that catch fire, put people with disabilities at risk, and cost too much. The indictments go on to suggest EVs create more carbon emissions than conventional cars.

Image: Kyle Field |

Here’s a real doozy. If the world had millions of electric cars and every one of those electric cars was plugged in to recharge at the same time, the demand for electricity would cause the electrical grid to melt down in spectacular fashion. Imagine transmission towers overheating and falling to the ground in a shower of sparks, littering the countryside with live high voltage wires just waiting to electrocute innocent people. Oh, the humanity!

While all of these fiendish pronouncements may seem ridiculous, the faithful minions funded by the Koch Brothers have no problem saying stupid things like those. That’s OK. They are paid — and paid well — to spread disinformation. Doesn’t mean we have to believe them.

A lot of those ideas are based on a kernel of truth. For instance, if every electric car in the world started charging at precisely the same time, that definitely would disrupt the electrical grid, especially in future years when there are millions more of them on the road. Of course, anyone with more than a fourth grade education should realize such a hypothetical scenario is totally unrealistic. But when it comes to spreading fear and doubt the Kochroaches hired by the fossil fuel companies are the best in the world.

The Netze BW Study

For the past 15 months, Netze BW, the utility grid operator in Germany’s Baden-Württemberg region, has been studying the charging habits of electric car drivers in its service area. The data collected has been compiled to create a new report that allays many of the fears about charging lots of electric cars simultaneously.

The research focused on the wealthy Stuttgart suburb of Ostfildern-Ruit. The data showed that all the households with electric cars plugged them in overnight but only half ever charged simultaneously. “Since the experience with the project we have become a lot more relaxed. We can imagine that, in future, half of the inhabitants of such a street will own electric vehicles,” said Netze BW engineer Selma Lossau, project manager for the study, according to Reuters.

Prior to the study, people with electric cars tended to plug them in as soon as they got home. Participating in the study helped some change their attitudes about charging. “At the start, I did not want to take any risks and charged frequently in order to feel secure. Over time, I changed my outlook,” Norbert Simianer, a retired head teacher who drove a Renault Zoe during the trial, told Reuters. “I grew used to the car and became more at ease in handling the charging process.”

Simianer and his neighbors were given electric cars and 22 kilowatt wall-boxes for their garages, together with two charging points in the street, all free of charge. In return, they gave up their normal cars and allowed Netze BW to monitor and carry out a deferred and scaled down charging process during a seven-and-a-half-hour period overnight.

Netze BW tried various options, either slotting cars in at the maximum 22 kW charging flow one after another, or lengthening the charging time for individual cars by adjusting the power flow, or combining both methods, Lossau said. Soon the study participants, who used apps to check the status of their car batteries, grew accustomed to the lack of instant charging capability because their vehicles could always handle their everyday commutes of up to 50 km.

Smart Charging Solutions

The implications for smart charging are clear. Just because a car is plugged in to a charger does not mean it needs to be charging all the time. Chargers that are connected to the internet can be turned on and off remotely by the local utility company to balance grid loads while still making sure customers will start the next day with a full battery charge.

Thomas Werner, a spokesperson for Siemens, which makes smart charging equipment, says, “Charging processes offer so much flexibility that the overload on the networks can be reduced by deferring loading times or reducing the load that is supplied. This happens through the digitization of hardware and software and with communication technology.” Using software to help protect aging power networks from predictable surges could also avoid costly hardware upgrades to parts of the 1.7 million km of distribution grids in Germany.

What Manufacturers Want & What Utilities Want

What EV manufacturers want is cars that can be charged in about the same time as it takes to fill a gas tank — 5 to 10 minutes, on average. What utilities want is charging infrastructure that will not force them to make expensive upgrades to the electrical grid. Drivers tend to think of fast charging as a good thing and slow charging as a detriment.

In Norway, EV drivers are learning to be comfortable with slower charging if it occurs overnight when their cars are not in use. A study by energy regulator NVE finds that Norway could be faced with spending $1.2 billion over the next 20 years for low and high voltage grids, substations, and high-voltage transformers unless it can persuade car owners to charge outside peak afternoon hours.

But that investment could be slashed by almost 67% if drivers adapt to charged in the evening and may fall close to zero if batteries are only plugged in during late night and early morning hours. NVE is now creating a tariff proposal which will penalize charging during peak demand times. Tibber, a Norwegian power company, already offers cheaper electricity for EV charging if you let it decide when your car is charged, while firms such as ZAPTEC offer ways to adjust charging to the available grid capacity.

The Rest Of The Story

In Germany as elsewhere, access to overnight charging is severely limited for people who live in apartments or condominiums. Plenty of detractors are ready to attack electric cars as being playthings for the wealthy people who can afford single family homes. The EV revolution must include all drivers, especially those without access to assigned parking spaces or who need to park on the street.

The challenge for utility companies will be to convince people to plug in, set the charging parameters, and let the utility company figure out how best to get the job done at the lowest cost. That will require people to readjust their attitudes. But if we can learn to let go and allow self driving cars to steer us down the highway, we should be able to allow our utility companies to find the right way to keep our cars charged. If doing so removes one more arrow from the quiver the fossil fuel companies have at their disposal to attack electric cars, so much the better.

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Steve writes about the interface between technology and sustainability from his homes in Florida and Connecticut or anywhere else the Singularity may lead him. You can follow him on Twitter but not on any social media platforms run by evil overlords like Facebook.


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