The Chevy Volt is an integral part of the Mueller, Tex., sustainable community.
Image: Courtesy of General Motors Corp.
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Environmentalists and renewable energy enthusiasts have been extolling electric cars for years, and now consumers are actually buying them. Electric utilities favor them as well, because plugging in the cars to recharge batteries adds to electricity sales. The utilities are worried, however, that if too many people in a community charge their vehicles at the same time of day, that synchrony would create spikes in power demand that could force the power suppliers to turn on expensive "peak generators" such as gas turbines—costs the utilities would rather avoid, and would ultimately pass on to consumers.
So would car owners all plug in at similar times? Early statistics from a concentration of electric car owners in Texas say, yes, they would.
The data come from a new, 280-hectare neighborhood in Austin, Tex., known as Mueller. The community is designed to maximize sustainable living, exploiting green building construction, intelligent appliances, smart electric meters and home management systems, as well as integrated residential, work, shopping and entertainment spaces. When complete, it is supposed to offer homes for 13,000 residents and jobs for about as many individuals.
Although energy planners for Mueller and many places worldwide had made assumptions about when and where electric car owners would charge their vehicles, real-world studies of actual consumer behavior were lacking. So Pecan Street, Inc., a research consortium based at the University of Texas at Austin, heavily instrumented homes throughout Mueller to take data every 15 seconds that would show what is really happening. The consumers have not been encouraged to use their cars in any particular way, and electricity rates do not change with the time of day, so costs do not influence their decisions.
Brewster McCracken, executive director of Pecan Street, and Chris Holcomb, data scientist at the organization, have just analyzed the first set of data, taken from 10 households over two months. "What we assumed turned out to be true," Holcomb says. "People come home at the end of a day and turn everything on." That means the television, computer, air conditioning, other appliances—along with plugging in their electric car for a recharge. The pattern held up across the two months—even on weekends, when it might be easy to plug in during the morning hours, and even though dozens of charging stations have been installed at convenient locations in and around Mueller.
The resulting demand on the power grid can be significant. The number of plugged-in cars begins to rise at 3 P.M. and continues through 8 P.M.—the same time period when home air conditioners are being turned on or up. Charging a depleted battery pack takes about four hours using a 240-volt line (similar to that for a clothes dryer), so the cumulative electric vehicle load peaks toward midnight. Most owners ended up charging their cars every other day or so, but no pattern emerged for preferred days of the week.
McCracken acknowledges that the data is only a start. As of mid-August about 40 Mueller residents were driving electric cars—mostly Chevy Volts, with some Nissan Leafs. (General Motors says Mueller has the highest concentration of Volts worldwide.) McCracken expects about 75 electric cars by the end of the year, and Pecan Street will expand its tracking. "There's much more to come," McCracken says.
Once 15 to 20 percent of residents in a neighborhood own electric cars, and if they behave like the 10 in Mueller, utilities could have real trouble meeting peak demand, McCracken says. The cars in Mueller draw about as much power as a home's central air-conditioning unit, and the two loads dwarf that from any other appliances. Pecan Street will be asking owners about when and where they use and charge their vehicles, and why they choose the options they do. The feedback might reveal ways utilities and regulators can adapt, instead of conjuring up incentives or rules that would "force people to behave in ways they don't want to, which would just put up a roadblock to using electric vehicles," McCracken says.
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48 Comments
Add CommentPeople plug in their cars late afternoon as a convenience. They want the battery to be recharged by morning when they'll use thecar again. Why not have the charger on a timer so that it activates in off-peak hours, say after midnight? The battery would still be fully charged by morning without impacting the power grid during peak hours.
Reply | Report Abuse | Link to thisThey *could* delay the charge until after midnight, but there's no incentive for them to do so, since rates for electricity use at midnight are the same as at 6pm. Furthermore, it creates a risk for the car owner that their car might not be fully charged in case they need it early or in case it charges more slowly than anticipated.
Reply | Report Abuse | Link to thisA solution to this might be an incentive system from the power utility itself. Currently some utilities ask customers to voluntarily install a remote shut-off in case of brownouts. In return they get a deal on their rates. Why not offer electric car owners discounted evening rates if they install a delay switch?
In the UK we used to have an economy 7 tariff for electricity. It ran for 7 hours from midnight, and was measured on a separate meter. People used to run their dishwashers and their washing machines and tumble driers on it. The big usage though was electric storage heaters which people charged up overnight and slowly released the heat when it was needed during the day. The electricity board (which at the time was nationalised- it was before Thatcher sold it off to her dodgy mates in the City of London) used to sell the electricity at a discount because it was at a time when demand was at its lowest and extra power could be produced cheaply on under utilised generating capacity.
Reply | Report Abuse | Link to thisYou get the drift. The point is this - you can modify customer demand using price. Economists call it the law of price and demand. So use price to encourage the customer to recharge their cars during the night when electricity demand is low. No extra generating capacity needed, no brown outs from charging cars. Rocket science or brain surgery it ain't.
I live in Southern California and have a Time of Use meter from So Cal Edison. I sell my solar power at peak rates and when I get off work, use my appliances at cheaper off-peak rates. I'll charge my car in the middle of the night when I join the EV club because it's better for me financially.
Reply | Report Abuse | Link to this"her dodgy mates"
Reply | Report Abuse | Link to thisI adore you British.
This 10 home survey is cute, but the real study underway is the EV project with thousands of vehicles and homes being tracked. The data is publicly available at http://www.theevproject.com/documents.php
Reply | Report Abuse | Link to thisInterestingly enough, time of use rates can sometimes create as many problems as they solve. If you look at the EV Project reports, in regions where time of use rates are effective, there is a bunching of vehicles charging at midnight when time of use rates kick in. The central generating plants are just fine as the demand is predictable, but the local transformers are where any problems may show up.
What is needed is smart grid technology when the vehicles and other appliances can be scheduled to draw current using minute by minute pricing information from the utilities, such that demand can be smoothed out and costs to the consumer minimized.
This is just proving the now 100 or so years old idea of giant power stations powering everything is a bad idea and these electric cars are only going to make the problems of the "grid" and communal power production even worse.
Reply | Report Abuse | Link to thisAlready I see ideas on manipulating prices of electricity to force people with less money to not recharge at the most convenient times, while those with money can recharge anytime.
Other patterns that will come up is constantly charging to full capacity to ensure never being low on power. Currently, a gasoline engine can sit for days with low fuel and have no effect and if needed can be instantly fueled up for use. To avoid the 4 hour charge wait, people will always charge when they can increasing demand. If electric vehicles do become prevalent, you will see charging stations at places of work.
The best option to take is to remove the grid. A home that produces its own power is more efficient and wastes less fuel producing the same energy for a car or anything in that house. The inefficiencies come from NOT losing heat and energy as electricity is transported on power lines and through transformers. Plus with each house producing power on its own, solar can be used and natural gas, which is less of an impact than coal.
Still, storing electricity is expensive, difficult and time consuming as well as temporary. Hybrid vehicles running on natural gas or perhaps fuel cells or something else will be better in the long run because fuel is simply an easier way to store energy.
In the end these electric vehicles wont really become prevalent. They cause far too many restrictions, most of which making the world about the radius of the distance the vehicle can travel, not many will accept this, so fully electric vehicles will simply not be prevelant.
Tesla's vehicles come complete with touchscreen and smartphone charge scheduling. Owners can simply plug in after parking and the charging begins at the programmed time.
Reply | Report Abuse | Link to thisAt 62 miles of range per hour of home charging (31 MPH for the base model) even mega-commuters can "fill up" in the wee hours when power demand from the grid is at its nadir.
"... each house producing power on its own, solar can be used and natural gas, which is less of an impact than coal. "
Reply | Report Abuse | Link to thisSolar produces nothing on a rainy day, and what happens to the pressure (voltage) in the natural gas grid when everybody's bloom box turns on at once. Natural gas produces as GHG's as coal and still emits deadly fine particulate emissions.
The Tesla products already do 200 some miles per charge and batteries are improved rapidly.
Use a two-stage charging. Overnight wall outlet builds up the charger - trickle charge takes longer but adds less load. Set them up right and the power companies will love the load-levelling of demand.
Reply | Report Abuse | Link to thisThe charger plugs in to the car anytime. Add a smart-cell and set the charge-up level as a function of above-average demand. Use the wall for the occasional serious run-down.
Really dudes, it is trivially simple minded to add a time-of-day algorithm to EV chargers to ensure a concentration of demand over the nighttime hours. You don't need any fancy-pancy Smart Grid, a high school student could EASILY design a charging scheduling program which would cost ZIP to implement in EV battery chargers.
Reply | Report Abuse | Link to thisAs has been mentioned all an owner wants is to ensure their vehicle is charged when they leave in the morning, not difficult to achieve that AND balance demand VERY effectively. And if you think that is a "terrible" issue, realize that a similar strategy is needed, desirable, economical and entirely achievable with present tech, for Heat Storage at night, called ETS or Electrical Thermal Storage or Ice Storage for daytime Air Conditioning. Again no Smart Grid needed, just a simple-minded time-of-day control program. I can develop you ten different effective versions next week if you are in a hurry.
So end result, and the objective is to use cheap, green nightime, baseload Nuclear Energy to store heat, cold and transportation energy for use in the daytime. Add to that, some chemical process, like Aluminum, Ammonia and Methanol production. By these means it is possible to supply virtually almost all our Electricity Demand, most of our Transportation Energy Demand and most Heating demand with cheap, sustainable Nuclear Energy.
By Far-and-Away the BIGGEST issue of intermittency is the OBSCENE efforts by Big Oil/NG & their Big Green subsidiary to push the nutty Wind Power Scam. Wind is the epitome of peak demand. Wind destroys cheap baseload power and converts it into a terrible new form of intermittent, fluctuating Peaking Power. A role "coincidentally" always filled by NG power.
Believe it or not, in Ontario when Wind peaks at night, as it often does, or on weekends, or in the Spring & Fall when demand is minimum, they usually spill Hydro or dump Nuclear, both at ZERO CO2 savings, ZERO cost savings, a TOTAL waste of money, for which Ontario citizens are forced to pay upwards of 13 cents per kwh for, power nobody wants. And that's with 1900 MW of installed Wind Peak capacity, and the Sleazoid premier Dolton McGoofy of Ontario is demanding another 8000 MW to be installed. Just friggin' unbelievable.
We in Spain have a special energy tariff to promote electric vehicle recharge during non-peak hours (at night, when de car tends to “sleep” and when wind energy production increases). Wind power energy generation is extremely variable and frequently increases at night, when it is not always possible to integrate this energy generated into the system if the electric energy offer is greater that the electricity demand. For this reason, recharging electric vehicles during night-time hours makes it possible to make the most of the energy available and reduces the possible disconnection of the wind farms should their production exceed the system safety limits which have been set.
Reply | Report Abuse | Link to thisThen again, electric cars can carry solar panels and be parked and driven in the sunshine. Big, heavy, blocky cars require powerful propulsion. Small, light, aerodynamic vehicles such as those with enclosed wheel wells, smooth underbellies, and wind cheating boat tails on their lee, these might roll mostly on solar in many places like here in Tampa, Florida. My own electric car, a converted velomobile, weighs half what I do. A "normal" car weighs ten to twenty times.
Reply | Report Abuse | Link to thisSadly, economic optimization and physics seem to require heavy electric vehicles, at least until battery costs drop further. Slower, smaller, aerodynamic vehicles suffer the high prices from low demand. We Americans seem bent on squandering as much energy as we can consume.
I hope all you volt drivers live on grids powered by wind, nuclear or hydropower. If not you should have bought an Escalade. it would have done far less damage.
Reply | Report Abuse | Link to thisWhy is our electric delivery so complicated? Solar, wind, can easily be leveled in their power delivery. You can use their power delivery to power pumps to move water (or name your poison) from a bottom tank to an upper tank. User gravity to release the H2O down hydro turbines to produce electricity. Use the power when available to move the water up and when not available it still flows down so that you don't have "peak power". The water is the one that produces power not wind and not solar. The holding ponds, lakes etc. can be used for recreation at the same time it produces electricity for us. No salmon cries, they are man made. Don't like H2O? Use captured CO2 to fill tanks to build pressure and then power pistons to produce electricity. It is not rocket science. No need for complicated batteries, capacitors, et al. It's simple physics. But oh wait... first the dinosaurs have to die so that we can figure out a way to totally skin a cat.
Reply | Report Abuse | Link to thisThis is the typical case of putting the cart before the horse. Our outdated electrical grid system has not kept pace with the demand. It's being held together with ducktape and bailing wire.
Reply | Report Abuse | Link to thisPutting greater demand on an outdated system with vehicles like the Volt and the Leaf is only adding insult to injury.
So much for that grandiose idea of the electric car saving the planet :-)
Reply | Report Abuse | Link to thisThe US utilities say they will have no problem charging 50% of the US car fleet with present generation.
In fact it's charging EV's that will allow the grid to be more eff, stabilized simply by charging them during demand dips, cutting them off during demand peaks. This can be simply done with just a cell phome modem for control.
Facts are generating grid power from EV's, each can be a 50-300kw alternator, so it can not only charge from the grid but put power back into it. This was done by Ford and ACPropulsion on the EV Ranger Ford produced in the 90's. Just needs to be implimented.
Modern EV's have charge timing built in, you just set it and if you'll need the EV faster, you just tell it in person or by cellphone and it's ready.
So many here just don't have a clue and so caught up in their 1 trick ponies like nuke power, etc and keep trolling here. No one thing will ever be the solution, not even 30% of it. No need to say everyone else is wrong when there are many solutions in energy, transportation.
Park at work charge at work. Go to the mall for 4 hours charge for 4 hours. Get a 2.5 hour charge at the cinema etc.
Reply | Report Abuse | Link to thisRemember the 5 LEED points for having a bicycle rack in front of your business?
Don't worry ...it's coming ... we'll get there .. I hope .. but not with out government legislation.
What a big pile of B***S*** this is about electric cars saving the environment. Where in H*** do you think the electricity comes from to power the car? The electricity is produced by burning fossil fuels in the main, then stored in storage batteries (in the car) that are produced by utilizing fossil fuels, then used at a loss of efficiency by electric motors rather than using the fossil fuels directly in an internal combustion engine. Spare me the nonsense. Wind and solar generation require a fossil fueled generator to be kept running (continuously) as backup for when wind and solar are not producing the required quota of juice. There is a tremendous amount of development required to overcome this problem which the "greenies" conveniently avoid facing.
Reply | Report Abuse | Link to thisHow dumb is this. Has the author not heard of timers? You don't need a high IQ to know you stager your usage to the time when your load is the lowest. Not only does it help the utilities it also helps you, your wires will be cooler with less current running through them. The copper conductors are just thick enough to cater to homes median load, its too expensive to put thicker wires. Remember you pay to heat your wires.
Reply | Report Abuse | Link to thisYa but it adds a buck a kwh to your power bill. Its expensive.
Reply | Report Abuse | Link to thisNext try to get your local environmentalists to approve drowning farmland,wildlands, forest lands , desert lands, native heritage lands, you name it lands, for a big pumped hydro storage site.
And what about all the methane from drowned plant life as it goes from spring time full to winter empty.
Nope not as easy as you might think.
The electric car manufacturers need to make a standard size removable battery for electric cars. Then, gas stations could all be outfitted with solar panels or wind generator, and keep stock and charge up of many of these standard size electric car batteries. Electric car drivers could then pull up and exchange their depleted battery with a fully charged one rather than fill up with gas. Each car may could run off of several of these easily exchangeable batteries.
Reply | Report Abuse | Link to this
Reply | Report Abuse | Link to thisCompare the behavior of the Department on work with references of citizens in Russia and in the United States and do not find differences. In both countries do not respond to my letters out of car design Bureau.
On the roof of the passenger car (between the car roof and insulation automobile salon) you can mount the heat converters of the surrounding возхдуха into an electric current, capacity up to 1000 kW. The operating model of the transducer designed, manufactured and showed coincidence of calculated the expected parameters.
When driving a car roof of the car will be обдуматься the air and from the air can be taken heat into electric current. This car does not need fuel, do not need a battery that does not need recharging.
You need to drive out the morons of the departments of work with letters of citizens and You will travel by car, which does not require fuel and does not require charging the batteries. But...
If we are able to adapt ourselves to the new pattern and they provide us with enough charging points, it is possible than many drivers will charge their vehicles while they are at work, ie.
Reply | Report Abuse | Link to thisI am a volt owner with a 240V charger station. I believe the simplest way to manage demand is to combine time of day rate incentives with smart charger stations. The charger stations already have wireless connectivity to the utility. The utility can determine the demand and manage it accordingly. This does not require a full smart grid to implement.
Reply | Report Abuse | Link to thisAnd if there is no wind or sun for a few weeks do they close down and everybody stays home?
Reply | Report Abuse | Link to thisEach car will have about half a cubic yard of batteries not just one.
Reply | Report Abuse | Link to thisThe utilities here in Hawaii give a rebate to install a device that allows them to shut off your demand during brown out possibilities. This device could be used to turn on the vehicle charger during low demand times.
Reply | Report Abuse | Link to thisPoorly researched article. Both Volt and Leaf, and I assume others, offer delayed charging options. I can set the timer to start charging at a specific time, or set it to finish by a specific time. My car is set to finish by 7:00 A.M., so the start time varies based on the amount of charge needed that day. A full charge takes 4 hours, so the earliest it ever starts is 3:00 A.M.
Reply | Report Abuse | Link to thisTime of use solves this as would the truth. Electric companies are not worried about firing up peaker plants. They enjoy paying very little and are more profitable now due to the low-cost of Natural Gas. The thing they fear is fees associated with slow demand response. Peaker plants start up fast. Battery backup modules even faster. Generators are looking at both.
Reply | Report Abuse | Link to thisHomeowners with EVs tend to install Solar PV arrays and that helps reduce daytime peaks. Some EV owners charge during the day off their own Solar PV arrays, no grid impact at all. Volt and Leaf owners are responsible and many will charge late at night to lower their grid impact.
Compare that to just using up the oil in 50-years. Do we just "do nothing" and let our grand-children deal with the Max Max scenario? Or use Science and come up with good planning, low resource use EVs and EREVs and make an impact now?
PA's Act 129 and Smart Meters simply are being rolled out in my area to turn off AC units via Smart meters. All this does is force peak power down somewhat at a tremendous cost. Nobody is advocating to a grand-scale what is needed most. That is conservation and personal responsibility.
Electric cars do have timers. Volt and Leaf easily can be programmed to start charging at 1am. Someone may have a 220V charger - then charge from 3am to 7am and have a Volt fully charged. A 13.3 kWh charge gives me a 47-48 mile range now in my Volt. That 13.3kWh is the energy of about 1/3 of a gallon of gasoline.
Reply | Report Abuse | Link to thisEventually, people will "get it". It will take a lot of political fighting to get there, though.
If all the electrical car owners start charging their cars after midnight, wouldn't we have the same grid load problem?
Reply | Report Abuse | Link to thisHow about the utilities companies have the electrical car owners register with them when they buy an electric car and charge their users a fee for consuming more power than the average household. With this money, the utility company can then install a line that is just reserved for electric car owners, a line that does not create an imbalance in the normal consumption grid and services heavy duty electrical power to the households that own electrical vehicles; these households require more power than average but they pay a fee for a special additional line to power their vehicles.
Reply | Report Abuse | Link to thisI own a Volt. The Volt DOES have a timer that lets me charge after 8:00pm. (OFF PEAK) The reason I program the car to charge after 8:00pm is that my charger is on a separate "time of use" meter and it is 1/4 of the price for me to charge after 8:00pm. This article is not well researched. EV owners have a strong financial incentive to charge at off peak hours. IT'S CHEAPER! This article fails to acknowledge this financial incentive. I was also able to have my charger and TOU meter installed for FREE. SO cost is not the issue. ALL EV's being sold today offer delayed charging options. EV owners will likely charge at OFF PEAK hours because they SAVE MORE MONEY.
Reply | Report Abuse | Link to thisFALSE. I have a time of use meter for my Volt. I charge after 8:00pm every night because it is CHEAPER for me to do so.
Reply | Report Abuse | Link to thisMy Volt DOES have a delayed charge timer. I also have a time of use meter that encourages me to charge after 8:00pm because it's CHEAPER. Most EV owners use delayed charging. This article is misleading.
Reply | Report Abuse | Link to thisALL EV's sold today DO have a delayed charge feature. I charge my Volt after 8:00pm every nigh because it's also CHEAPER. I have a time of use meter. I save money when I charge at night. Most EV owners DO use delayed charging. This article is poorly researched and mis-leading.
Reply | Report Abuse | Link to thisI have a time of use power meter. My Volt uses delayed charging every night. I charge aftet 8:00pm because it's CHEAPER! Most EV owners DO use the delayed charging feature because it saves money. This article is poorly researched and very mis-leading.
Reply | Report Abuse | Link to thisSo does the Volt. So does the Leaf. So does the Ford EV's. They ALL have delayed charging features built in. Most EV users DO charge at off peak hours because it's CHEPAER.
Reply | Report Abuse | Link to thisYou don't need to add anything. ALL EV's sold today already HAVE delayed charging options. Leaf, Volt, Tesla, Ford... ALL Have delayed charge features built in. EV owners have a strong incentive to charge late at night because it is CHEAPER.
Reply | Report Abuse | Link to thisFALSE.
Reply | Report Abuse | Link to this1. Even if the EV is using electricity generated by Oil... It uses far LESS oil to move the car. Did you know it takes nearly two gallons of oil to make 1 gallon of gasoline. Power plants burn unrefined fuel oil far more efficiently and cleanly than a car can burn gas. (That took a whole extra gallon of oil to refine.)
2. EV's can use electricity that comes mostly from DOMESTIC fuel sources. Most of the electricity in the USA is generated by coal, natural gas and other sources that d NOT involve foreign oil.
3. EV's are the ONLY type of vehicle that has the flexibility to use power generated by Solar, Wind, Atomic, Geo-Thermal, Hydro-Electric, Coal, Natural Gas and oil. No other type of vehicle can offer that kind of flexibility.
I use delayed charging every night on my Volt. I charge after 8:00pm because it saves me CASH. Get a TOU meter. Save your self some CASH.
Reply | Report Abuse | Link to thisProbably NOT. The daytime industrial peak loads far exceed any power consumed by EV's... Even if every home in the USA has one.
Reply | Report Abuse | Link to thisIn fact... Charging EV's at night helps power companies balance loads and better estimate the community needs.
I am disappointed with the lack of depth in this article. I am a Volt owner. You should make it clear that the vehicle comes with a fairly sophisticated charging program that allows me to delay the start of charging to whatever time is needed to achieve full charge by 7 AM. This means that my vehicle is only drawing power during the "wee" hours of the morning. Also, it is apparent that my (very large) electric utility is not worried. They are even planning to convert all their company vehicles to EVs. There are so many ways to solve the demand issue, yet the article only suggests potential problems. SciAm can do better!
Reply | Report Abuse | Link to thisFacts are that ECOtailty who has installed thosands on EVSE charging locations in homes and the public have data shoing 80% or more charge Off Peak at night. My LEAF has a timer I set for 11 PM to charge but plug in when I get home and then go to sleep.
Reply | Report Abuse | Link to thisALso over 40% of EV owners also have GRID Tied Solar and hel the GRID During Peak Tie Of Day. The EV is the first smart GRID appliance ! Get the facts
Actually, there is a fairly elegant solution in the works to handle the problem of clustering and grid overload by EV's. It's outlined at variablegrid.net,
Reply | Report Abuse | Link to thisand we are looking for an aggressive set of entrepreneurs to help us exploit it.
The current batteries last longer if charged slowly. We haven't invoked that level of technology into the chargers yet. Full charge by x AM is ideal. Also since AC and the charger are near equal loads one can run them in ping-pong fashion to level the demand in a house. Controllers that can "talk-to" the water heater, dryer, AC etc. can level/manage the residential load a lot. We've just scratched the surface with the technology we already have at our disposal.
Reply | Report Abuse | Link to thisIn California, PG&E and other energy providers have offered lower nigh-time energy rates to encourage EV drives to learn to use their charge timers and charge after midnight! I wouldn't do it any other way!
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