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How may EVs does it take before demands become an issue for the Grid?

thegruf

Active Member
Mar 24, 2015
2,290
2,070
indeterminate
Just wondering about this.

Already there may be local issues at SCs when all bays are occupied whether full charge rates are available for all vehicles.

But could this actually become an infrastructure issue, where the software maybe in conjunction with the utilities has to start budgetng for some diversity of charge times.
Overnight is generally good due to lower overall demand, but what about commute times/evenings?
 

JanoSicek

Member
Aug 21, 2015
32
2
Switzerland
Some back of the envelope calculations:
Total electricity generated in 2014: 20000 TWh (world), 4400 TWh (USA)
If you drive a Tesla 10000 miles a year, at 300 Wh/mile that is 3MWh per Tesla car.
Therefore if all electricity in the world was used for driving Teslas only, the planet would support 6.66 billion cars. USA alone would support 1.5 billion cars.


Apparently USA has about 250 million cars, so if USA boosts its electricity production by 16%, everyone can drive a TESLA. That would save 130 billion gallons of gasoline per year. And Wolfram Alpha says this about the quantity:

omparisons as volume:

MSP18551eaieg2c8de0398i0000160f1d7a1e6ff651




MSP18581eaieg2c8de0398i00002ci1763ab4975cgg







 

tessnme

Member
Jan 23, 2014
26
19
Napa CA
Since most of us are charging during off peak usage times, I doubt EVs will cause any grid problems at all. What little impact we have on peak usage will be offset by lower electricity usage for refining oil 24/7. BTW, power companies are expecting the increased use of solar to move the peak usage time from 1-7pm to 4-9pm and are changing their rates accordingly.
 

thegruf

Active Member
Mar 24, 2015
2,290
2,070
indeterminate
^ good find - thankyou.

Interesting that they already are considering utilities "talking" to the cars to increase the diversity of charging times as I speculated.

And yes, I guess the grid overall could probably cope (there's usually quite a substantial amount of peak reserve power that can be tapped into) but like everything there's always the weakest link, one cable, one transformer etc. so this will more likely initially show itself as individual streets, neighorhoods.
 

MsElectric

Active Member
Oct 11, 2014
1,604
22
New York
Not as much of an issue as you'd think because due to energy conservation issues electricity use has actually started to go down or plateau in many developed countries.

With the additional of solar and wind, the grid should be able to handle whatever EVs are bought...
 

David99

Active Member
Jan 31, 2014
4,856
7,164
Brea, Orange County
If my calculation is correct: the USA uses aprox 3600 tWh per year. Night time demand is about 3/5 of daily use. In other words 2/5 would be available during the night without any grid upgrade or additional power plants whatsoever. Assuming an average EV needs to charge about 30 kWh a night the current grid could theoretically handle ~ 130 million EVs. In reality it probably isn't quite as simple without upgrades. But even if we just take half of that. That's still 60 million EV that the grid as it is now can handle. We don't have to worry for a long time.

My calculation 3600 tW * 2/5 / 365 (days) *1000 *1000 *1000 (from tW to kW) / 30 (what each EV needs) = 131 million.




Electricity Demand
 

Khatsalano

Member
Mar 21, 2015
669
118
San Mateo, CA
Also, keep in mind that refining gasoline takes a TON of electricity. It actually takes more electricity to refine gasoline per mile, than actually straight-up using the electricity to direct-drive the car. You will find that the largest commercial utility customers are Chevron/Shell, etc. :) They use more electricity than anybody.

The grid can handle it. What the grid is not yet able to handle, is bidrection distributed generation with solar ... that is actually much more of an imminent problem to solve than growing EV charging demands.

- K
 

Saghost

Well-Known Member
Oct 9, 2013
8,224
7,088
Delaware
Just wondering about this.

Already there may be local issues at SCs when all bays are occupied whether full charge rates are available for all vehicles.

But could this actually become an infrastructure issue, where the software maybe in conjunction with the utilities has to start budgetng for some diversity of charge times.
Overnight is generally good due to lower overall demand, but what about commute times/evenings?


The grid can take it. A while back I attempted to assemble the problem and perspective from the top down on GM-Volt using EIA data and other government sources as best I could:

What would happen if everyone switched to EV?

It's not a problem, once you look at the big picture. Let's pull together the facts and do a little math...
smile.png


Over here, the US used 136.78 billion gallons of gas in 2014.

If you look at this, the total US grid electricity production for 2014 was 14.78 Quads of electricity.

These two looked at together show that US drivers drove about 2.98 trillion miles in 2014.

Incidentally, that suggests 21.8 mpg overall average (2.98 trillion miles/136.78 billion gallons.)

A quad of electricity is a quadrillion BTUs - at 3412.14 BTUs per kWh, it is about 293 GWh per quad.

For the sake of this exercise, I'll assume that all those 2.98 trillion miles are suddenly being driven by RWD 85 kWh Model Ss. Not only is this a more viable car for most people than the others, it's also one of the less efficient pure EVs in the current market (due to the weight and performance gearing) - so it should give a conservative answer.

Over here, the EPA rates that car at 38 kWh per 100 miles including charging losses.

2.98 trillion miles at 38 kWh per 100 miles gives 1.132 PWh - 1.1 trillion kWh. That's a huge total, right?

But here's the perspective on that - it's only 3.86 quads. In the electricity chart I gave you above, we spent 4.79 quads (1.4 PWh) on residential electricity usage alone in 2014.

With that perspective and considering that the current grid experiences a 2:1 ratio of consumption from the middle of the afternoon to the middle of the night, it should be clear that the grid as a whole should be fine.

There could be local cases where residential neighborhoods that were already near the edge might need some improvement in the infrastructure, but it should be minimal and localized - and the variable nature of EV charging could help a lot...

If the cars involved are indeed Model Ss, with always on net connectivity and extensive software, there's no reason they can't be tied to the power company directly through the web. What if the power company gave you a 20% discount on all your charging power in exchange for the right to choose exactly when and how fast you charge, with a guarantee that they'd always give you a battery charged to your charging target before you leave in the morning?

That sort of deal would be a no-brainer for me, and I'd think most of us - but the power company would probably come out ahead on it as well. If they have a bunch of cars charging, they can ramp the rates up and down or suspend/initiate charging a lot faster than they can spin up most types of standby power to respond to load changes - and the distributed nature of the load would let them balance the response across transmission lines too.

The next step, vehicle to grid (V2G) where they could actually use a little power from you battery to meet the demand, requires a lot more infrastructure and control and may not happen, but just the flexibility to shape what would become ~21% of their overall usage would be a huge boon and might save them (and hopefully thereafter you) money on meeting spinning reserve requirements if the system for adjusting the charging is robust enough to convince regulators.

Of course, there aren't 216.8 million Model Ss to drive those 2.98 trillion miles, and there won't be for some time. We certainly have the ability to build enough car bodies, and I believe that with all the other things we use them for, we probably have enough capacity to build the power electronics and the drive motors. The problem is batteries...

Tesla sees this coming, and that's why they are building the Gigafactory. If you look here, you'll see that Tesla is hoping to build 35 Gwh of batteries at the Gigafactory in 2020 and every year thereafter. That's more than the entire industry produced in 2013 - and still a drop in the bucket for total conversion.

Those 216.8 million Model Ss up above need 18.4 TWh of capacity - 526 years of production at 35 GWh per year. Even if they were 216.8 million Leafs instead, they'd still need nearly 5 TWh - two orders of magnitude more than the Gigafactory can produce.

After spending a while trying to digest this chart, I think it's telling me that in 2014 we introduced about 16.8 million new cars into the fleet. (Which means the average car lasts 12.9 years in service somewhere.) If we were building only EVs, we'd need 1.4 TWh of production (or, eventually, recycling of batteries from old EVs) for Model Ss or 370 GWh for Leafs - between 11 and 40 times the planned Gigafactory capacity.

Lithium is fairly plentiful, and "mining" it is both relatively easy and not horrible for the environment (mostly achieved by concentrating salts from ground water, especially geothermal type deep underground water,) but we're going to need to do a whole lot of it, even though the Model S battery only has about 20 pounds of Lithium in the ~1200 pound pack.​


 

aesculus

Still Trying to Figure This All Out
May 31, 2015
4,529
2,599
Northern California
Most Calif utilities have time of use rates for EV's that convince customers to charge off peak, thus avoiding the issues. Simple solution that requires zero or little automation other than what is already built into the cars chargers.
 

tliving

Member
Mar 8, 2014
751
102
New England, USA
There's a race on between solar and EV and I think Solar is winning. I think 100% will be able to go EV if the solar movement continues. More than just the electricity I need to drive my Model S is generated by SolarCity.
 

TaoJones

Beyond Driven
Nov 10, 2014
3,064
3,028
The Americas
Also, keep in mind that refining gasoline takes a TON of electricity. It actually takes more electricity to refine gasoline per mile, than actually straight-up using the electricity to direct-drive the car. You will find that the largest commercial utility customers are Chevron/Shell, etc. :) They use more electricity than anybody.

The grid can handle it. What the grid is not yet able to handle, is bidrection distributed generation with solar ... that is actually much more of an imminent problem to solve than growing EV charging demands.

- K

Similar to to what I was going to add. How many EVs will it take before refineries reduce their ginormous power consumption requirements? A 5% reduction, collectively, would power one's choice of small countries.
 

Saghost

Well-Known Member
Oct 9, 2013
8,224
7,088
Delaware
Also, keep in mind that refining gasoline takes a TON of electricity. It actually takes more electricity to refine gasoline per mile, than actually straight-up using the electricity to direct-drive the car. You will find that the largest commercial utility customers are Chevron/Shell, etc. :) They use more electricity than anybody.

The grid can handle it. What the grid is not yet able to handle, is bidrection distributed generation with solar ... that is actually much more of an imminent problem to solve than growing EV charging demands.

- K

Do you have data for the first point? The best studies have read say that it's a misconception, that the 6-8 kWh per gallon to refine that you find in lots of places online is actually total thermal energy input and 90% of it is provided by burning fuels at the refinery.

I mostly replied because of the second point, though. I'm not seeing how distributed solar generation could possibly be a threat to the grid...

Adding distributed generation to a distributed load reduces the loading at every transformer and substation, requiring less capacity. Why is this going to lead to an overload?
Walter
 

nwdiver

Well-Known Member
Feb 17, 2013
8,331
11,359
United States
There's a race on between solar and EV and I think Solar is winning. I think 100% will be able to go EV if the solar movement continues. More than just the electricity I need to drive my Model S is generated by SolarCity.

Yup... solar is definitely winning... the US added ~6.2GW last year... that's ~9TWh of additional generation from solar alone or ~27B EV miles.

You would need ~1.8M cars driving 15k miles each to cover 27B miles.... the US only added 123k to it's EV fleet last year :crying: (yeah... people suck... what're you gonna do?)

Not even close to being an issue... we're adding >10x as much solar production as EV consumption. Solar is also growing faster than people are choosing responsible transportation so that gap is growing.

To the refining point... there's another thread that discussed that... the amount of ELECTRICITY is actually small... <400wh/gal. Most of the energy used is not electricity.
 

pkz0125

Member
Aug 11, 2015
38
2
Cary, NC
There's a race on between solar and EV and I think Solar is winning. I think 100% will be able to go EV if the solar movement continues. More than just the electricity I need to drive my Model S is generated by SolarCity.


+1. It would be awesome when the model s is built using solar energy and charged using solar too. I am getting my car in a month and solar panels in 2-3 months. My car won't cause any issue for the grid :).
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,088
173
Colorado
I mostly replied because of the second point, though. I'm not seeing how distributed solar generation could possibly be a threat to the grid...

Adding distributed generation to a distributed load reduces the loading at every transformer and substation, requiring less capacity. Why is this going to lead to an overload?
Walter

There are two threats to the grid from Distributed Solar PV, technical and economic.

The technical threat has to do with large percentages of "dumb," correlated Solar PV. Adding and removing generating capacity is a big deal for the utilities. Normally, they rely on a "law of large numbers" averaging effect for the total load to change slowly. The problem is that events like clouds going over a neighborhood or city are very correlated events; when the amount of generation from Solar PV is large and comes and goes in unison, managing the generation to match that is a big deal. This is not an issue when solar is a fraction of a percent of total use, but when it becomes 10's of percent, problems occur. I personally believe that the best solution is to add storage that is something like a half hour of maximum production, then use that to make all "ramp up/ramp down" events to happen over 30 minutes or more. This allows the grid to have time to react.

The second, economic problem is caused by net metering which effectively uses the grid as a big battery that you don't have to pay for. The maintenance of the grid costs money. Right now, the connection fee for most residential customers does not cover those costs. I very much believe in net metering as a way to encourage Solar PV installs, but I also recognize that there are costs to the utility of being the "battery" for solar producers. Perhaps, some sort of additional connection fee for Solar PV, say $1 per kW DC should be added to the base connection fee; that would be an additional $10 per month for a 10 kW; maybe $0.50 per kW for a system with local storage and slow ramp up/ramp down and $2/kW for systems without local storage to encourage customers adding local storage. As more and more Solar PV goes in the fee for non-battery systems probably needs to go up to keep the grid stable.
 

Bangor Bob

Member
Jan 5, 2015
670
487
Bangor, ME
To the refining point... there's another thread that discussed that... the amount of ELECTRICITY is actually small... <400wh/gal. Most of the energy used is not electricity.

Even at "just" 400wH/gallon, when you consider we demand 19 million barrels a day, the electricity used adds up very quickly. I make that 320GWh/day, 120TWh/year. A continuous demand of slightly more than 13GW (roughly equivalent to ISO New England's minimum nighttime demand), or just about 9 1.5GW nuclear reactors 24/7/365.

And then we burn it at an average thermal efficiency in the low 20% range, and lose another 10-30% of that by the time it gets to the wheels... Yeeesh.
 

mknox

Well-Known Member
Aug 7, 2012
10,103
1,894
Toronto, ON
The biggest issue is not energy, but rather demand (specifically, concurrent demand). For most utilities, the choke-point is the local distribution transformer. For the most part, generation, transformer station and feeder capacity is adequate. So too are the service conductors into the home which are sized to the size of electrical service you have. On the other hand, the local transformer (up on the pole near your house, or the green box on the lawn) is sized taking into account the diversity of most electrical loads. Typical loads are not all on at the same time. They cycle on and off. So the 6-10 homes that may be connected to a single transformer won't overload it due to this diversity. These transformers are also designed to have a "cooling period" overnight when loads are typically lower and temperatures are cooler. Now throw in a couple of continuous load EV chargers and you have trouble. Big trouble if everyone starts buying EVs and charging them all at the same time. In some cases, a larger transformer can be substituted and financed through the increased revenues the utility will see, and in other cases, utility demand response technology can communicate with EVSE and "schedule" charging sessions throughout the night so that everyone's car is not charging at the same time.
 

Bangor Bob

Member
Jan 5, 2015
670
487
Bangor, ME
There are two threats to the grid from Distributed Solar PV, technical and economic.

The technical threat has to do with large percentages of "dumb," correlated Solar PV. Adding and removing generating capacity is a big deal for the utilities. Normally, they rely on a "law of large numbers" averaging effect for the total load to change slowly. The problem is that events like clouds going over a neighborhood or city are very correlated events; when the amount of generation from Solar PV is large and comes and goes in unison, managing the generation to match that is a big deal. This is not an issue when solar is a fraction of a percent of total use, but when it becomes 10's of percent, problems occur. I personally believe that the best solution is to add storage that is something like a half hour of maximum production, then use that to make all "ramp up/ramp down" events to happen over 30 minutes or more. This allows the grid to have time to react.

The second, economic problem is caused by net metering which effectively uses the grid as a big battery that you don't have to pay for. The maintenance of the grid costs money. Right now, the connection fee for most residential customers does not cover those costs. I very much believe in net metering as a way to encourage Solar PV installs, but I also recognize that there are costs to the utility of being the "battery" for solar producers. Perhaps, some sort of additional connection fee for Solar PV, say $1 per kW DC should be added to the base connection fee; that would be an additional $10 per month for a 10 kW; maybe $0.50 per kW for a system with local storage and slow ramp up/ramp down and $2/kW for systems without local storage to encourage customers adding local storage. As more and more Solar PV goes in the fee for non-battery systems probably needs to go up to keep the grid stable.

Multiple studies are already finding that utilities are underpaying for solar at net-meter prices, vs. the benefits received by the utility from distributed solar generation. The trick is to count all the benefits the utilities receive, rather than just counting raw kWh in/out. Here's a synopsis of one: Maine PUC’s Solar Power Study Released Today Shows Enormous Benefits
 

MrClown

Autosteer Beta Tester
Oct 3, 2014
222
46
Denver
Cottonwood's points are exactly right. I'll add that solar doesn't generate at night which is when most EVs will charge. Imagine a world (maybe 50 years from now) where everyone has solar + EVs. We generate a ton of distributed electricity during the day but then use a ton of electricity at night to charge our EVs. Local storage is the only good solution I can see for this whether it's at the customer location or at the neighborhood or substation level. Fortunately, someone is stepping up in a big way to facilitate exactly that solution (thanks Elon!). Battery storage will keep solar's continued growth viable, stabilizing the grid and defending against the naysayers who can't see past the end of their nose into our inevitable renewable energy future.

- - - Updated - - -

To the refining point... there's another thread that discussed that... the amount of ELECTRICITY is actually small... <400wh/gal. Most of the energy used is not electricity.

Energy is energy. That "most" that is not electricity could be used to make electricity instead or do lots of other things, no?
 

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