U.S. Electricity Generators Can Handle Electric Car Load, For Now

By · March 22, 2011

One of the key concerns with the growth of electric vehicles is whether the United States electric grid will be able to manage the growth of vehicles plugged in. This is particularly a concern in areas that have experienced rolling brown and black outs during summer months when the air conditioning is cranking on high. Add to this, potential fresh concerns over nuclear power plant safety and one of the first questions I often get asked about plug-in electric vehicles (PEVs) is whether our grid can take the additional draw from recharging all these vehicle batteries.

This is not a simple question to answer. Obviously, there is a component of consumer behavior. How will consumers recharge the vehicles? Will they all plug in at the same time? Electricity costs in the select areas with time of use pricing certainly steer most consumers to charge at off-peak times and many studies show that consumers who charge at home do just fine. However, many consumers will likely have some concerns about having enough mileage to get home (particularly initially) and may be inclined to charge during the day. So, smart grids and smart overnight charging are being developed to help ensure that when PEV charging is happening it isn’t bringing down the whole town.

But all of this raises the question of where do we need to be most concerned about this? In Pike Research’s recent “Electric Vehicles Geographic Forecasts” report, I attempted to address this by answering two key questions: Where will the vehicles be? And, how much power will they draw?

In figuring out where the vehicles will be, I examined data from manufacturers, consumer survey data, census demographic, and household data to forecast that New York City, Los Angeles, San Francisco, San Diego, and Chicago will be the MSAs with the largest numbers of PEVs by 2017.

LEV Sales

But this is only half the story. Using this forecast data and overlaying it with the electric utility service areas, I generated a forecast for the utility service areas. By using industry averages for PHEVs and BEVs of 14 kWh and 22 kWh batteries with recharge times of 4.25 hours and 8 hours, respectively, I calculated the draw for specific electric utility service areas. This is purely a hypothetical maximum draw, which assumes everyone plugs in and charges their vehicles from zero to full all at the same time – all of which I admit is highly unlikely.

By 2017, Southern California Edison and Pacific Gas & Electric are the two electric utilities facing the greatest exposure with 498.6 MW and 466.5 MW potential electricity demands, respectively. However, when measured as a percentage of generating capacity (2009 figures), Pacific Gas & Electric is the most likely to find themselves in a crisis first, since 466.5 MW accounts for about 6% of their total generating capacity. The electric utility for the largest single PEV MSA, Consolidated Edison, has a potential draw of 241.9 MW. Since Consolidated Edison buys wholesale power instead of generating their own (in theory) they can just purchase additional power to make up for the extra demand.

Plug-in Electric Vehicle Electricity Draws

Since this measure of total potential draw is a worst case scenario and highly unlikely, this tells me that PEV energy draws, even in California, are likely to be easily handled in the near-term. However, the total cumulative number of PEVs in the United States by 2017 is 1.5 million vehicles. That’s a pretty small number. So, will electric utilities be prepared for twice this number of vehicles by 2025? And don’t forget that electricity demands from non-vehicle sources are growing too. That seems a little less certain, but one thing is certain, planning for more generation capacity needs to start now, if it’s going to be online in time.


· Anonymous (not verified) · 7 years ago

I've posed this question a couple of times on this site and most recently to my local electric utility - so far with no answer. I have heard for coal-fired generators the spin-up time is so long that they can not be shut down at night when demand lessens. I interpret this to mean that some level of heat must be maintained at all times in the boiler and that if there is no demand for electricity during these off-times the energy is essentially wasted. Is this correct? The implication, of course, is that if EVs could be charged during those off-peak hours, the electricity would be essentially free.

· Travisty (not verified) · 7 years ago

You are correct. At night there is a energy being lost. From my understanding power plants that use a fuel (gas/coal/nuclear) all ramp down - so they are not burning as much fuel - but they never stop. It takes a large amount of energy to get plants to their running state.
It also depends on the type of reactor and how the enery is produced. If the plant is the type that has steam rise from the top and turn turbines then the system can be slowed much more. If the plant uses water in a critical state to go through the system to turn the turbines then there is not much delta between max power and min power since the water needs to be kept in the critical state.

P.S. That's why off-peak enery is so much less. They're charging you money for energy they would not have gotten money for if you weren't using it.

· · 7 years ago

A lot of that excess electricity simply goes to ground overnight. The utilities would love to sell it to us to charge our cars. It's daytime charging that has them nervous.

· Paul Neuhausen, MSCIS (not verified) · 7 years ago

I live in Los Angeles (jsut joined EVoSC yesterday) and am currently in negotiation with the Los Angeles Department of Water and Power (LADWP) to install a Coulomb-style charger on my driveway that is connected to my panel and, ultimately, to the grid. However, I have already decided to install an appropriate number of solar panels (six+ to ne phased in slowly) on my home to feed directly into my EV-to-be (A 1997 GEO Prizm to-be-converted to a ________ EV motor) thereby mitigating any more "strain" (pull) on the grid and of course the cost. In So Cal, all of that sunshine is free - truly free - and I am going to take advantage of it!

· Chris T. (not verified) · 7 years ago

It's not exactly "spin up time"—the spinning reserve is in fact always spinning—but rather thermal and pressure stresses. You don't want your coal-burner going cold! (Other than for actual maintenance, that is.) If you do trip off line, you still have to keep the turbine rotating (though not at full speed) until it is completely cooled.

Basically, if you're not generating power, you keep the plant running at "neutral", which requires that you continue burning coal, just not as much as when you're generating power.

(See http://en.wikipedia.org/wiki/Boiler#Supercritical_steam_generators and http://www.scribd.com/doc/31543426/Coal-Thermal-Power-Plant for some data.)

(I guess Travisty already said most of this)

· Alexei (not verified) · 7 years ago

I do not want to sound anti EV, but would it be more beneficial from CO2 point of view, to spend money on building energy storage systems that accumulate the off-peak electricity and release it back during the peak time, rather than spending all that money on subsidising EVs?
As all that coal/uranium will have more kWatts actually sold to customers and the kWatt will cost less and will make EV charging cheaper.
And on the other hand, that extra energy storage capacity will make renewables more efficient as it will balance its unpredictable nature and decrease the need for a coal station standing by to pick up from wind turbines when the wind suddenly drops or clouds hide the sun from the solar panel.

· Anonymous (not verified) · 7 years ago

@Alexi - with a bi-directional charging station and / EV-based 'energy storage system', you get a substitute for gas, i.e. a mobile energy storage system - and all the wars required to obtain the oil as well as all the planet-killing CO2 emissions required to get from point A to B. (Incidentally, Iraq wasn't the first oil war; WWII was.)

That said, you have an interesting point. There is something called 'pumped storage', essentially man-made hydroelectricity. As I recall, it is supposed to be about 80% efficient. (What is the figure for state-of-art batteries by the time manufacturing and disposal are factored in?) Besides water I believe about a 1500 foot elevation drop is required.

But I'm wondering what scale is envisioned for such systems. Specifically, would a subdivision-scale system employing a water tower work? A subdivision scale for renewable energy systems is really the most cost-effective anyhow. It could be much more easily coupled to whatever form of energy storage system proves most cost-effective. (That would seem to be a viable architecture for even a smart-grid, fossil-fuel based base load power grid.) The generating system could use thermal solar rather than PV-based power, something that is impractical and not cost-effective for individual homeowners but right now more cost-effective (thermal) as a renewable energy technology.

The real problems seem to be socially / economic based, not problems with technology. Pumped storage is likely to require more infrastructure investment by government. It seems to me however that this is really worth looking into, particularly in the West where global warming is threatening to play havoc with nature's water AND hydroelectric energy storage system - the snow pack in the Rocky Mountains.

· · 7 years ago

@Alexei. would it be more beneficial from CO2 point of view, to spend money on building energy storage systems that accumulate the off-peak electricity and release it back during the peak time, rather than spending all that money on subsidising EVs?

This isn't an either or scenario. EV tech drives energy storage. As battery technology improves, the applications they drive increases. Remember 15 years ago the general public only viewed batteries as something used to power toys, watches, radios, and start a car. Now because of cell phone, and laptop demand battery tech has been adopted well by the power tool industry and soon automobiles and motorcycles. It would seem logical that as batteries become more efficient they would progress to a home or subdivision level. As a matter of fact Panasonic promised to develop a whole house battery a couple of years ago it might be delayed or vaporware, but it still seems like a logical path.


I've wondered if power generation or storage becomes more localized if DC current will become more dominant?

· Dave K. (not verified) · 7 years ago

Anonymous: There was actually an oil component to WWI, ships were being converted to run on oil instead of coal and all that "Lawrence of Arabia" stuff was partly about preventing German access to the middle eastern oil.
Pumped storage is very inefficient and limited to regions with appropriate geography, batteries are much better and if we will "rent" them to the utility and they don't have to buy their own so much the better.

· Anonymous (not verified) · 7 years ago

@Dave K. - As to “Pumped storage is very inefficient and limited to regions with appropriate geography” , see the Wikipedia entry for pumped storage hydroelectricity, http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity -
“Taking into account evaporation losses from the exposed water surface and conversion losses, approximately 70% to 85% of the electrical energy used to pump the water into the elevated reservoir can be regained.[1]”

This article should probably be re-titled, however, because I read somewhere you don’t really need water; you can use a compressed gas (air?) Since I last looked at the referenced Wiki article, this has been added:
“The use of underground reservoirs has been investigated. Recent examples include the proposed Summit project in Norton, Ohio, and the Mount Hope project in New Jersey, which was to have used a former iron mine as the lower reservoir. Several new underground pumped storage projects have been proposed. Cost estimates for these projects are higher than for surface projects, but their use might greatly expand the number of pumped storage sites.” …
Instead of pumping water uphill, the pumped storage idea can be inverted, pumping air under water.”
In the real world, “renting” batteries to the local utility is probably the way things will fall out.

· Anonymous (not verified) · 7 years ago

@Dave K. - Where did you get the "Lawrence of Arabia" stuff information? I read Yergin's "The Prize" several years ago but don't remember that. I knew about Churchill and the conversion of the English fleet to run on oil but didn't include WW I because from everything I've read the advantages of oil were still 'theoretical' and only definitively proven by the outcome of that war.

WW II was, on the other hand, a much purer specimen. See Yergin and The Next Nagasaki - Nuclear Fears Stalk The World , by Yoichi Shimatsu - 2011-03-19,
“World War II was in essence a contest for fossil fuel. An energy-hungry Japan invaded China for its coal and Indonesia for oil reserves. Nazi Germany's blitzkriegs were aimed at oil fields in Romania, Libya and the Caspian Sea region. The United States and Britain fought the Axis Powers to retain their control over the world's fossil fuel, and they're still doing the same in conflicts with OPEC nations and to control Central Asia and East Asia's continental shelf.”

· Alexei (not verified) · 7 years ago

Battery will require some materials, which need to be mined and often in a hostile country, plus they do not last 20 - 50 years. And how many batteries are required in order to store enough power for a big city to last for an hour or 2 during the peak time?
A pumped water energy storage can last 100s of years without the use of rare materials and without additional expense from individual home owners (on purchase of the battery and rewiring of the house, plus its replacement and maintenance).
Even though the efficiency is just around 75% it is still good, as all the recovered energy would have been wasted any way.
Another interesting idea was recently tested in the UK, see http://www.highview-power.com/wordpress/?page_id=8 or http://www.highview-power.com/wordpress/?page_id=438
The above approach uses liquefied air and waste heat to generate power, that could be useful for example for cooling Data Canters and they generate huge amounts of waste heat and require a lot of energy just to cool the computers.
Also combined with some mirrors, can make a solar station more efficient, as at night the wind turbines provide power for air liquefaction and during the day the solar rays give it an extra energy to expand rapidly.
All that saved energy/carbon can lead to decreased demand on Natural Gas, which could be used to power cars with the LPG (or big lories and buses which at the moment would not be practical with batteries) and use less of the foreign oil.

· Clive Sinclair (not verified) · 7 years ago

As the CEO of Tesla said regarding batteries powering EV's "If I were to make a prediction, I’d think there’s a good chance that it is not batteries". I could not agree more. Heavy, expensive and currently take too long to charge.

In the UK the grid can currently cope with 1m electric vehicles. We currently have around 30m fossil base vehicles. Also despite the largest offshore wind farm in the world and the largest onshore wind farm in Europe the output for the last 48hrs in the UK has been less than 0.5% of our total generated output (a few hundred mw). We need more solar and tidal projects in the UK and less reliance on wind - which is proving to provide less output than predicted.

By moving away from batteries (say capacitors) to power EV's, it would mean grids would only have to cope with short bursts - rather than heavy continuous loads overnight.

· · 7 years ago

All 5 of the MSAs that you studied in your analysis have Natural Gas utilities for their residential population. Between now and 2017 you will start to see the utilization of Natural Gas Fuel Cells being used more predominantly in these markets. These NG FuelCells are highly efficient, with the purpose of generating your own home electricity from natural gas. It seems practical that many EV owners would be willing to install an NG FuelCell for their own home charging when the cost / KW for such home generated power is less expensive than the cost/KW from the Electric Utility. Natural Gas is something that America has in abundant supply, and relatively inexpensive compared to Oil, and Nuclear.

· JRP3 (not verified) · 7 years ago

Some incorrect comments above. At night electricity is not run to ground, output is reduced. As mentioned coal plants can throttle down, just not quickly. Load is fairly predictable so coal is throttled down slowly each night, nuclear is steady base load, hydro can be steady base load or excess can be diverted to pumped storage.
Using capacitors would not change the overall load on the grid other than to increase potential peak loads, which is not what we need. The same total energy would still have to be provided. Frankly I think Musk is wrong, caps don't have anywhere near the energy density of batteries, they are no where near cost competitive, and EV's simply can't take advantage of the million cycle capability of caps. Batteries will be replaced by better batteries, not supercaps, unless something magical like EESTOR actually exists. I'm not betting on it.

· · 7 years ago

@Alexi I don’t consider Chile, China, and Australia as hostile countries. I also can say that the wiring needed to accommodate a whole house battery is no more complicated then adding a charger for a plug in vehicle. The only thing needed would be AC/DC converter after the meter, which could be placed in the battery pack itself, the battery, and then an inverter.

With that said, the idea of pumping water has some concerns for me. Issues stem across the spectrum of the technical, and socioeconomic.

First would the storage be salt water or fresh? Fresh water is not as abundant as most people think and it is essential for life. Taking it from an ecosystem just for storage is not the best usage on a world scale. Salt water is abundant but very corrosive systems would need constant maintenance. They would also be limited to the coasts. Also would the storage be a reservoirs or tanks? If reservoirs are used it would be it could only be done in certain parts of the country. What about climate and weather conditions? If a reservoir or tank is frozen how do you get the energy back or pump extra water into it? That makes it seem like it would further limit areas which this could be applied.

Now for the socioeconomic concerns. The grid for the most part was developed by the government then sold to private industry in most cases. At this point it would be the responsibility of those companies to improve their systems, not the government. If such an infrastructure where developed with government funding how would the people benefit? The private companies are not obligated to lower the price of power once they are able to reduce their output. Also whole house battery tech places power management in the hands of the end user. Once people are more aware of their consumption they will consume less. Water also becomes an expensive commodity. I’ve seen this first hand in India were one state dams a river that would flow into another one. Fights for water rights could be a huge problem.

Nevertheless, I don’t believe in either or scenarios. Taking away the EV tax incentive would only extended the monopoly of gasoline powered vehicles in this country. With the way gas prices fluctuate that would only hurt more people in the long run. It’s not the complete answer but I believe it is an effective step.

After going over this response I’ve just realized that the concern over EV’s effect on the grid is just more of the same fear and doubt propaganda towards EV tech. As other new technology in this country developed I’ve never heard of a study of its affect on the grid. For example there are over 250,000 cell phone towers in this country and the number is rising. They run 24 7 and require air conditioned shelters at the base of their towers to keep the electronics from overheating. No concern or study about the effects to the grid. The same could be said for the server farms popping up across the country.

· Alexei (not verified) · 7 years ago

Water storage is not the silver bullet. It is just one of the technologies to make our use of energy more efficient, it would not consume too much of the fresh water as it can use 2 lakes and pump water between them, it only needs to replenish the water lost to evaporation.
You could solve some energy usage problems at home, using battery technologies, but I am not convinced that there will be enough materials to make enough batteries to cater for the needs of industries (factories, data centres, malls, offices, etc), these enterprises need a lot of it, more than the households and it should be there every working day without the influence of the weather. Imagine that you want to shop on the amazon and you get an error page "Sorry, the wind is not blowing".
A single office building for 500 work places can consume a 0.5 megawat an hour during the work hours (for lights, computers, air conditioning, heating, etc). How big the battery should be to cater for its needs? For 8 hours of operation it needs about 4 MW which is 4000 KW, with prices prices of of 500$ per KW it is 2,000,000$, with 300$ per KW it is 1,200,000$. Which is a lot of money for an office building, price of the battery would need to go down to 100$ per KW. But taking into the account the competition for the batteries between cars, offices, home users, factories, shopping malls, etc it will take a lot of time to reach to that point.
See http://www.fhc.co.uk/ffestiniog.htm, 2 of these stations supply energy to entire region of North Wales UK for a couple of hours, massive 360 MW. And you do not need to replace the complete storage media (batteries) every 10 years, it can last for centuries.
My point is, that it will be much more efficient to spend subsidies on building energy storage facilities (liquid air, pumped water, any other) which can supply multiple types of consumers, rather than spending it only on one type of consumer (the cars in this case). And also it will make renewable sources much more reliable for the industries to relay on.

· · 7 years ago

Price per kWh depends on the technology used. Since size and weight don't really matter in stationary applications you can use much cheaper chemistries than lithium.

· · 7 years ago

For stationary applications it might be possible to use industrial scale versions of something like a vanadium redox battery. I don't know if large format batteries can be cheaper and more practical than something like pumped storage though.

· Alexei (not verified) · 7 years ago

I am for any efficient type of energy storage. In case of a battery, as long as it does not become a hazard to life in case of a leak, fire, any type of an accident I am for it.

· Anonymous (not verified) · 7 years ago

Pumped storage vs. batteries questions:
1. Every time you cycle a battery don’t you ‘wear’ it? I would like a bi-directional charging station but I’m not sure I would like to use it – or let my local utility use it – very much unless they pay me big time (or at least for normal wear and tear).
2. (This being a site where you can just pose questions and let others do the work – past education or present calculations) I’ve wondered what the pumped storage capability for a moderate sized community water tank would be. It seems some kind of distributed storage to go along with distributed generation would be preferable. Some of the lost economies of scale could be made up by eliminating distribution losses. (As for those who would scream about esthetics, maybe we could sprinkle a little plutonium across their esthetically pleasing flat landscapes.)
3. I live in about as arid a part of the US (that still has people) as you could find – Arizona. There are at least two pumped storage facilities in AZ, near Phoenix and the Salt River. More to the point every year during the monsoons the washes run like rivers. That water just runs to ground. It is true that people 10,000 years from now (if there still are people) may be able to use it, but for those of us members of the ‘me’ generation, we want it now! And furthermore, even here in AZ (I think) we could use it responsibly. If you did nothing fancy and just constructed a traditional pumped storage facility with two reservoirs separated by a 1500 ft vertical drop, both could be covered and uncovered by pontoon-based covers to control evaporation if necessary. There are plenty of mountains around Tucson with the necessary elevation differences. (I would offer ‘environmentalists’ the same plutonium alternative. Of course we could ALL use less. But I suggest the place to start is with people driving BMWs not Priuses.)

· · 7 years ago

Battery cycles depend on many factors, but generally shallow cycling a battery has very little effect. If you're talking about V2G for your EV it would mostly be used for short peak loads and only a relatively small portion of the pack capacity would be used when needed.

· JJ - from Canada (not verified) · 7 years ago

If we have to build new power plants, that will create jobs and jobs to run them afterwards.
If the government can afford to subsidize the oil industry, it could divert some of that money to build more power plants.

· · 7 years ago

@Alexi I agree that pumped storage power plants have some benefit. Looking into this I noticed that this technology is quite old. No cutting edge research is required and utility companies are for the most part making a lot of money. These companies don’t need an incentive from the government to build these types of plants. It is in their best interests and they have the money to do so. Here is an example of one of many of these plants that already exist in the US. The companies that own it are currently performing a major upgrade to it.


Like I stated before, there really isn’t a need for an either or scenario. Even your example of the UK plant proves it because the UK also has an incentive for people to buy electric cars. You should find out how the money was gathered for that plant before condemning EV incentives. Plus the grid is mainly powered by coal not a great power source but at least it is local and does not force the country in to war.

BTW, if there was an error page on Amazon stating "Sorry, the wind is not blowing.", I would be a regular customer. I might even buy something there every time the wind blew:) And if they told me that my shipment would take 6 weeks to get to me because they only used electric vehicles for delivery, I would even be happier and recommend them to friends.

· Heather (not verified) · 6 years ago

"Off peak"? If the majority of people are plugging in their cars at night, then this will create demand. Won't that demand raise electricity cost?

It's not call off peak just because it is night, it's called off peak because demand has normally been down during those hours. If everyone is plugging their cars in, it may not be "off peak" for long!

Also, where do people plug in if they do not own their own homes? Or if their cars are parked in outdoor parking lots without assigned parking? Or outdoors during snow and rain?

· · 6 years ago

You're right that demand is normally down at night. EV charging at night will, of course, increase this demand but it will be a long time before this new EV demand comes close to requiring the electric companies to have to add any generating capability to handle it. This means that the electric companies will win along with the consumers. At some level of EV usage, it may be necessary to add generating capacity, at which time, EV charging costs would be about the same as normal electricity costs.
Actually, what may be more likely is that as renewable energy sources increase, EVs may start using a lot of it. One problem with most renewables (solar and wind in particular) is that they are intermittent. The nice thing about EV charging is that an EV can usually charge any time as long as it has enough to do its daily driving. This actually will help the electric grid start using renewables.
Just as it took a while for apartment building owners to start putting in cable TV, it may take a little longer for apartment dwellers to be able to charge EVs at home. Clearly, changes will have to be made.
Snow and rain don't affect EV charging at all. All plugs are watertight and don't energize the circuits until both the car and the charging station recognize they are plugged in. Remember, in the coldest parts of the US and Canada (ND, MN, MT, etc) most parking lots have electrical outlets in them anyway to allow cars to plug in engine block heaters. These places are used to plug in outdoors in snow and rain already.

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