Smart Grid can help with prime-time charging of EVs

Smart Grid can help with prime-time charging of EVs
People can’t all charge their electric cars simultaneously. Electricity is perishable. It’s helpful if your power use is relatively even over a 24-hour period. Credit: Thinkstock/People can’t all charge their electric cars simultaneously. Electricity is perishable. It’s helpful if your power use is relatively even over a 24-hour period. Photo: Thinkstock

Norway leads the world in new car sales of electric vehicles, but how will charging all those EVs affect the Norwegian energy supply? Researchers at the Norwegian University of Science and Technology are helping to develop Smart Grid solutions that will ease the crunch caused by powering our transportation with electricity.

When people with EVs come home from work in the afternoon, they plug in their cars to charge them. That results in an extra peak in electricity consumption in the afternoon.

"We're moving towards a different kind of power use," said Professor Olav B. Fosso, professor and director of the Energy strategic research area at the Norwegian University of Science and Technology (NTNU).

This peak may eventually become a major challenge for the electrical grid.

"We could have big voltage problems, with limited transmission capacity within the distribution system," says Fosso.

Capacity could also become a problem. Large variations in consumption throughout the day are challenging. Electrical power is perishable. That means it's an advantage to have relatively stable power use over a 24-hour period. Renewable energy from the wind and sun has to be used immediately.

Fosso says Norway is lucky to be able to regulate its hydropower.

Water reservoirs allow adjustments in the power supply, but very few countries have that ability, and even in Norway high consumption at certain times of the day poses a challenge.

EV numbers on the rise

Afternoon charging of isn't a problem—yet. But the orders for electric cars in Norway show that growth won't stop with the almost 75,000 EVs already on the road, including hybrids.

"Nothing suggests that this development won't continue," says Fosso.

Cars have different charging power and storage capacities. Storage capacity is related to the car's range. Mitsubishi's capacity is around 16 kWh, while the Nissan Leaf has a capacity of around 20 kWh and Tesla, 85 kWh. Battery size determines the charging time for a given amperage, with typical charging efficiency ranging from 4-8 kW. Home chargers provide long charging times, but that may become problematic when a lot of people charge their cars at the same time in residential areas. Quick charger installations require a higher current feed and thus a stronger electrical grid.

Fast chargers of around 20 kW are now available for home use in the United States. If this type of rapid charger becomes more common in Norway, so will problems.

A Smart Grid can affect your wallet

Afternoon peaks in power use are common, because people come home and turn on heaters and appliances. But this peak will also be increased when people come home and plug in their EVs.

That's when people have to get smart in how they use the power. A Smart Grid— which uses new technology to better leverage the electrical grid— will likely be an essential part of the solution.

NTNU's Faculty of Information Technology, Mathematics and Electrical Engineering (IME) is involved in developing a Smart Grid in Norway. Their research will have a direct effect on consumers' electricity bills.

At the moment, when consumers get an electricity bill, they pay it and probably don't think about it again, since they might have used the power they've paid for several months previously.

But a Smart Grid gives consumers the potential to save both energy and money. For instance, you can adjust your consumption so some of it happens when electricity is cheaper. The goal is to be able to see when the price is at its lowest.

"Then you'll notice a difference immediately," says Fosso, who says he thinks this feature will make it easier to save, too.

If electricity is much cheaper at 10 pm, maybe you'll time your car charging for then instead. Or maybe you'll wait a few hours to turn on the washing machine.

Saving energy is as good as producing it

Developing a Smart Grid is an enormous task with many variables. In the future, private households will produce more of their own electricity, which complicates the picture further. Then it will be all the more important for us to use the grid more efficiently.

There isn't much you need to do to reduce consumption. Preliminary experiments show that Smart Grid helps people to save around 10 per cent on energy costs, and peaks loads are reduced by around 15 per cent.

Of course, many of us have plenty of room to reduce our electrical use, and which we may also need to do.

"One kWh saved is as good as one kWh produced. We need to bring the end users on board," says Fosso.

Explore further

A plug fit for every car

Citation: Smart Grid can help with prime-time charging of EVs (2015, December 21) retrieved 16 July 2019 from
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Dec 21, 2015
All these "problems" have been forecast for decades, and are being taken care of by system and device design. Chargers have the ability to come on when you want, not just when they are plugg4d in. Time of Use utility rates pretty much guarantee you will charge them at night, when the utility wants to run its baseload plants full-out.

My utility watches and plots the loads on the circuits with customer inputs, ready to make any infrastructure improvements required. Producing power with home solar and using electric transportation actually helps the power company. I generate at peak, but buy power off-peak, both of which are good for them. It helps balance the diurnal loads.

When I was in Technical Services for PG&E in the 1980's, we were already funding electric vehicles through EPRI, and had years of data on early uses of electric postal vehicles.

This would have been a good article several years ago.

Dec 21, 2015
Perhaps if there was a truly smart grid where electric rates during peak hours or more expensive than in nonpeak hours there wouldn't be such a rush to draw power when demand is greatest.

Dec 21, 2015
Enviro, it has been that way already for decades for large users, and recently for residential users. I am on Time of Use rates, since I found out I could save $750/year over the tier-structured rates. I would be put on them anyway, for the electric vehicle and the solar system, both recently acquired.

Check with your power company for a free rate analysis. Most will examine your usage and let you go on the most advantageous plan for you.

Dec 23, 2015
Time of use is pathetic. Here the power company decided 3 times zones throughout the day. In the morning is max peak, afternoon mid peak, ,and evening is max peak. In spring they chose a day and the mid-peak and max-peak flip. Like suddenly everyone decided to start using their power at mid-day.

How about if people are actually charged what the electricity costs? If you could look at a meter on the wall that shows this hours price of electricity you could actually make decisions about whether you will charge your car or not.

On the other hand, your higher power devices can be programmed to watch the power costs and run when the cost is acceptable. This is the system they promised when they forced tax-funded smartmeters on everyone's houses.

Dec 23, 2015
Then install solar panels already! Transmission lines.. Who needs transmission lines when power is generated WHERE it's used?

All those huge factories that need power? What's that flat roof covered in gravel doing for you? Want to cut your bill? Install solar panels. Make that roof work for you.

All those home that want 20KW chargers? Install solar panels! All day long the transmission lines are pushing power out of your neighborhood. As soon as you all get home, well I guess if you're not at work then you don't need to power the machinery you're in charge of operating, so turn that off and use the power load removed from the grid to charge your car at home.

Dec 23, 2015
And then when you consider usually it's the government in charge of building and operating power plants, how about if instead of paying out billions (plural) of tax dollars to install solar panels you just subsidize solar panel installation instead? At less than a dollar a watt for solar panels, a billion dollars makes a billion watts when the sun is up and it's needed most.

No wait... That's if the government BUYS the panels for you like they do for gas power plant companies instead of subsidizing them. Subsidize them at 20% and now you get 5 billion watts of production for a billion dollars.

Yep. 5 Gigawatts available for free, only when you need it most, all for less than the price of one gas plant that can only produce 850 MW maximum, while burning obscenely costly natural gas.

Dec 23, 2015
The sad fact is that the grid cannot supply power to a meaningful number of electric vehicles if they are a primary source of transportation. Now if your vehicle requires 20KWH each day and you are willing to purchase enough battery storage to enable only drawing power during the hours where renewables can charge your batteries then you deserve a huge discount. BTW you will need that discount to make that storage investment make any economic sense. If solar and wind become cheap enough to accomplish these reduced rates without ratepayer or government subsidies then the switch to renewable energy will have been a total success!!!!!

Dec 23, 2015
"The sad fact is that the grid cannot supply power to a meaningful number of electric vehicles if they are a primary source of transportation."
The grid is already ahead of the automobiles, and I expect it to stay that way in California, where we probably have the most EVs in the country. Mine is already monitoring the use for our EV, with the eye to upgrade lines if necessary. They want that PV power and off-peak EV usage.

Dec 23, 2015
the grid cannot supply power to a meaningful number of electric vehicles if they are a primary source of transportation

It can if there is intermediate storage (as the article clearly states). Such storage could be 'capacitor stations' or using flow batteries instead of the solid kind.

There's a lot of viable solutions out there already being field tested (all too many, I fear...because no one wants to make the first move and get it wrong)

Dec 23, 2015
"Such storage could be 'capacitor stations' or using flow batteries instead of the solid kind."

Yes, I could envision flow batteries being part of the solution but not super caps. Super caps are a great source of peak power lasting 10s of seconds but quickly become impractical when you are trying to store KWHs of energy.

Dec 24, 2015
I'm more thinking in a combination of battery stations and supercaps. The batteries (of whatver kind) there for storage and the supercaps for quick charging (being replenished in the lull between cars driving up to the station, people going in to pay, etc. from the battery storage)

I find it not very problematic that storage is taking a bit to get into gear. There had to be a business model for it first. And that just wasn't the case until renewables made up significant part of the energy production or EVs became a real option. But now that time has come (as the article demonstrates).
Storage and smart grids can go hand in hand, here. The smarter the grid, the less storage is needed.

Dec 24, 2015
Just Compare 1:50 Against 1:1000 Ratio!
What had Obama Done in 8 years?
Being Close to North Pole, Shitanta Delivers from his Rear!

Dec 24, 2015
Just Don't Dynamite the Mountains for Boulders/Stones.
Just Like Flyovers, Start building Reservoirs up, over there!
All Day under the Sun, Extra Energy will send the water upstairs & in nights water comes rushing down over the turbines.
Always other nations have to take the lead? Western Nations go to 3rd world nations with awful lot of Sun for Oil only, but Never Collaborate for Cheap Solar Energy! Development of a World Grid is of Great Necessity for the Ever Energy-Greedy World.

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