More Fun With Numbers…

Posted on February 9, 2013 by Zachary Shahan

Here’s some more fun with numbers from one of our readers that we thought was worth sharing. The topic is: “if we all drove EVs and got 100% of our EV electricity needs from wind.”

Wind turbine & EV in field via Shutterstock.

First, some key assumptions:

Average miles driven per US car in 2010 was 13,476.
EVs use roughly 0.3 kWh of electricity per mile.
That’s 4,043 kWh needed per year to drive 13,476 miles.
That works out to 11 kWh per day.

The DOE estimates that, in 2007, the number of US cars on the road was 254,400,000.

If all our cars were EVs, we would need to generate 2,798,400,000 kWh per day. Rounding up, let’s make that 2,798,500 MWh per day.

The average size of a wind turbine in the US has a power capacity of 3 MW. Using the average size, a wind turbine will produce 30.1 MWh per day (3 MW x 24 hours x 43% capacity).

To power 254.4 million EVs, we would need 92,973 3MW turbines.

At 0.25 acres per turbine, the total land required would be 23,243 acres.

For some perspective, the island of Manhattan contains 15,168 acres; Disney World covers 30,500 acres; and Washington, DC covers 43,712 acres.

Add in some losses for transmission and battery charging and the point is that we could get all the electricity needed to charge every car and light truck in the US with two Manhattans, one Disney World, or less than one Washington, DC.

Zachary Shahan (2293 Posts)

I'm the director of CleanTechnica, the most popular clean energy website in the world, and Planetsave, a leading green and science news site. I've been covering green news of various sorts since 2008, and I've been especially focused on solar energy, electric vehicles, bicycling, and wind energy for the past few years. You can also find my work on Scientific American, Reuters, Think Progress, GE's ecomagination site, several sites in the Important Media network, & many other places. To connect on some of your favorite social networks, go to zacharyshahan.com or click on some of the links below.

RealityBitesU

What if the cars did not need hardly any outside charging ?

What if they had consistent trickle charging always going on ? What if they had:
1) PV built into the body providing consistent trickle charge anytime any light is present (i.e., thin film like the new one that uses ALL incoming light and has a +90% efficiency),2) permanent magnet DC high efficiency generators in the wheels so trickle charge also occurs every time the wheels move, 3) Ultra capacitors used in order to cut down on battery drawdowns during high power demand times such as initial acceleration (these can extend a battery charge up to 15 times when used with portable power tools), 4) low efficiency magnetic field inducing generators used in regenerative braking for recapture of some energy (or maybe try some flywheel technology, which I haven’t seen used yet, the other items however are all ready to go), 5) Altairnano Nanosafe nano coated titanium dioxide batteries do not heat up, test up to 20,000 recharges and can be stacked to provide extended ranges and
6) High efficiency motors by UQM or Dyson. Such a car would rarely need to be “plugged in” to the grid. It would sell very well throughout the world, put more money back into the hands of the people because they would not have to be buying unneeded outside produced polluting energy, erasing much carbon presently being produced alleviating some of the climate change, change the geopolitical structures throughout the world, i.e., middle east, Iran, Venezuela, ETC., help alleviate the need for us to be spending such great sums of money and precious resources including military on the Middle East, cut down on polution and the attendant health problems and costs incurred by such. Yeah, I guess it makes too much sense and the greedy oil and gas barons and their lackeys in Congress won’t allow it.
- Bob_Wallace
  
  #1 – Highly efficient PV is not affordable at this time. And I don’t think there is actually any “+90% efficiency”. Plus there would be a market acceptance issue. You can only take design so far from what people are use to and have something that sells in large numbers. A PV covered car would likely be hard to sell.
  
  #2 – The reasons the wheels move is because something is providing energy to move them. Harvest energy from the moving wheels and you require more energy to make them move. You loose energy overall due to system inefficiencies.
  
  The rest of your suggestions – I’m sure people are looking at them. Some things sound like they should work but they either don’t or cost too much.
  
  The oil companies do have a lot of power but it is decreasing. Look at all the manufacturers who are making PHEVs and EVs.
  - RealityBitesU
    
    Big business and political interests have for decades run and financed surreptitious rumour and disinformation campaigns to derail those who they oppose and to support those things they promote. Lately, one term for individuals who are so employed and active on the internet in the comment sections, is “trolls”. You sir, are obviously one or you are very unintelligent and full of self-importance saying “I don’t believe” therefore it won’t work. Naw, I think you are a troll.
    - Bob_Wallace
      
      OK, Reality. Let’s have a reality check.
      
      1) Who makes a 90% efficient thin film?
      
      2) How do you propose violating the laws of physics in order to use the car’s battery to drive the wheels and attach a generator to the wheels to send electricity to the car’s battery without loosing energy in the process?
      
      Here’s a hint on what you need to deal with. EVs are about 90% efficient.
      - RealityBitesU
        
        I am not going to get sucked into your games. All anyone has to do is read your initial attack to see what a crock it is. Can’t even spell, you “loose” (sic) energy and “loosing”(sic) energy. I repeat I don’t even think you are an armchair scientist, I think you and your buddy are trolls, just like I encountered in the comment sections during the last political election, trying to guide things. “Some things sound like they should work but they either don’t or cost too much.” Sounds like the same B.S. modus operandi the “conservatives”, read big business trolls, used to attack any progressive, truthful or humanistic proposal set forth during the last election. It is attack and attack and airily dismiss with a load of B.S.. And you totally do not understand what different kind of generators there are and how they operate. You are probably incapable of understanding the differences between the two types of generators I propose and how they work. Oh yeah and you claim people won’t buy a car that recharges itself independent of the grid giving free charges/fill-ups because “A PV car would be hard to sell.” due to some “market acceptance” problem that you created out of thin air in your mind and state like it is a fact.! What a load of B.S.! You are obviously a troll and just as with the political arena I am sure you have other aliases and cohorts as well and you all visit other websites. By the way if you want to know about the 90% efficiency PV get off your ass and research it, unless that may cause you to “loose” (sic) your mind. The bad part is this planet is in trouble and we are having to fight this fifth column within our ranks.
      - Bob_Wallace
        
        You know, I do have a spelling problem. And a proof reading problem.
        
        However I don’t have the sort of “loosely connected to reality” problem exhibited in your thinking.
        
        Where is that 90% efficient thin film solar you build your argument on?
        
        What trick have you found that let’s you violate the laws of physics and create a perpetual motion machine?
        
        And finally, since communication skills have become a topic, have you never heard of “paragraphs”?
      - RealityBitesU
        
        You are making things worse for yourself. If you would READ what is written instead of just yammering, you would have seen my direction to you regarding the PV in the above. Your obvious mischaracterization re: my proposal for a highly efficient machine that recaptures much energy AND also has outside energy coming in from the PV coated body is just flat out misleading!. My proposal only states “Such a car would rarely need to be “plugged in” to the grid” (for most usual daily driving) due to its high efficiency, its recapturing of energy and its outside replenishing energy source of PV electricity. Your B.S. that it is a “perpetual motion machine that would violate the laws of physics” is the SAME B.S. mischaracterization or outright fabrication that the “conservative” trolls would employ in the comment sections during the last election. Seamus says, “Woof, woof.”
      - Bob_Wallace
        
        I did read what you wrote. I read it the first time you posted it and I questioned two of your proposals. You have not adequately addressed those questions to date.
        
        In your first post you talked about building EVs covered with “thin film like the new one that uses ALL incoming light and has a +90% efficiency”.
        
        You have yet to identify who makes that 90+% efficient thin film.
        
        You also wrote “permanent magnet DC high efficiency generators in the wheels so trickle charge also occurs every time the wheels move”.
        
        You do realize that EVs use regenerative braking, do you not? Do you know how it works?
        
        Stepping on the brake pedal causes the vehicle to start producing electricity which is fed back to the batteries in order to increase efficiency. Those systems do not capture 100% of the energy, some is lost to friction/heat and battery inefficiencies.
        
        The drag created by generation slows the vehicle.
        
        Your idea of harvesting energy from the wheels any time the vehicle was in motion would be like driving with the brakes on. You’d have to increase power to the motor in order to maintain speed. And a significant portion of the energy flowing from the batteries would not be returned to the batteries.
        
        You’re not getting anywhere by name calling.
      - RealityBitesU
        
        Like I said you should read what is written and not just keep yammering. There are many types of generators, that operate in differing manners. If you would have read what I initially wrote you would see that I differentiated between the two I proposed and outlined what they were. I suggest first you actually read what was written then you do some research on what was written, including the operating principles of the two differing kinds of generators I mentioned therein. You obviously have no clue as to how a DC permanent magnet generator works. More than that I won’t say because you are not serious, at all and you need to make some sort of effort and not just come up with your airily dismissing claims as I outlined in an earlier reply. With regard to the PV like I already said, get off your hind end and research it. You are wasting my time.
    - http://zacharyshahan.com/ Zachary Shahan
      
      Haha, Bob is not a troll.
      
      He’s one of the strongest EV advocates I’ve ever met.
      
      But he’s realistic about what is likely to make it to market and what’s not.
Anon

About 24% of the population is below 18 years of age.
If you assume that they are not diving, then the 254 million cars on the road would need to be reduced to around 193 million.

There is, also, a proportion of the remaining adult population that due to age or other circumstances are not able to drive. This would, also, reduce the possible number of vehicles imn the road.
http://MrEnergyCzar.com/ MrEnergyCzar

Maybe Fox will say we don’t have any wind… well done Zach.. I think land based wind runs at 30% of capacity and offshore 40% but that’s not the point here…

MrEnergyCzar
- Bob_Wallace
  
  http://en.openei.org/apps/TCDB/
  
  Click on the Capacity tab.
  
  Hover your cursor over the bar/whisker.
  
  25% of all US turbines have a 43% or better capacity rating. I think it’s safe to assume that future installations will be with the latest technology and best siting practices and should be in that range. 43% is the median of the ‘best 50%’.
  - http://MrEnergyCzar.com/ MrEnergyCzar
    
    Great stuff Bob. Looking forward to Cape Wind finally going up… I’m guessing the cape production will be like 60% of capacity, it’s always windy there…
    - Bob_Wallace
      
      Higher capacity.
      
      -and-
      
      More of the generation will be during daylight hours when demand is higher. While offshore wind is more expensive it is also more valuable. More power when it’s most needed.
Otis11

So for 4.5X the land area of Disney world we could make the US 100% wind powered and have 100% EV.

That actually sounds completely reasonable. Pair that with solar on most south facing roofs and it becomes even more practical.
- Bob_Wallace
  
  Absolutely.
  
  Put panels on east and west facing roofs as well. They will produce about 80% as much as panels on south facing roofs. But they will extend the solar day. East facing panels will start producing sooner than south facing and west facing….
  
  Right now we’re seeing the price of electricity plummeting on sunny days in Germany. A rather modest amount of solar has knocked the heck out of the normal daytime price peak, leaving morning and evening peaks. Some E/W facing panels would whack those peaks.
  - Otis11
    
    Yeah, and I believe if you implement time of use pricing for both the grid buying solar power and selling power to consumers that it will take care of itself.
    
    Instead of a feed in tariff just pass a law that says the utility must by Consumer End RE for 80% of the retail sales price at the time of production and that will balance itself out. One it gives Distributive solar a fair playing field as production distribution is about 20% of the cost of electricity IIRC and as the noon peak falls people will be incentivized to put panels at other orientations.that will not only meet their demands, but other’s demands as well.
    
    I really think that’s the solution. If you passed that and a pollution tax that established a price for SOx, NOx, particulate matter and maybe even COx with NO EXCEPTION that increased at a predetermined rate. Setting this rate so that would make it uneconomical to emit these pollutants in 10 years or so and we could be a completely clean economy extremely rapidly without significantly impacting economic growth as long as they cannot change it without 10 years notice so that the economy could make long term economic decisions with a high degree of certainty.
Shiggity

Some more numbers.

People who have wind turbines on their land typically get 3,000-5000$ of rent money per year per turbine. This is basically free and reliable income for 25 years. No farmed crop comes close to the money you can make from simply putting wind on your land.

A modern wind turbine is around 1,000,000$ per MW (this is just the turbine, no installation). This is probably less now with more advanced designs. But it’s a good general reference point.

The only problem with these numbers are rare earth metals. Computing rare earth metal supply vs. how much used in each turbine is tough though. We have solar though, Silicon makes up 1/3 of the Earth’s crust
- Bob_Wallace
  
  It looks like we can build wind turbines without uses rare earth metals.
  
  http://www.naturalnews.com/033647_wind_turbines_rare_earth_metals.html
  
  And there are more REMs than some people expect. Often people will look at what is being produced in a year and think that indicated what we could produce. As new uses for materials appear we look harder for new sources.
  
  http://blogs.ei.columbia.edu/2012/09/19/rare-earth-metals-will-we-have-enough/
  
  And we can recycle these materials. We’re basically looking for enough to manufacture the first full generation of wind turbines and then recycling the worn out ones.
- Otis11
  
  $3,000-5000 is an older statistic (In Iowa anyways). In Northern Iowa the people I know who have them get $5000 for the small turbines and some of the larger turbines can get over $7000 per year!
http://www.facebook.com/jeff.king.14224 Jeff King

Im confused, you go from talking about 100% of cars being EV to using the numbers if 10% were EVs please clarify
- Bob_Wallace
  
  I think a lost decimal point wandered onto the page.
  
  25.4 doesn’t get used in the math. 2,798,500 MWh / 30.1 = 92,973
  
  We’ll call child protective services and find it a good home.
  - Bob_Wallace
    
    Hey, we got to keep the little lost decimal point.
    
    And we gained a “4″.
    
    (‘To power 254.4 million EVs, we would need 92,973 3MW turbines’ used to read 25.4.)
Amber

Great info, it would make a great infographic.
Amber
- Bob_Wallace
  
  How about some reader produced infographics?
  
  Creative people want to give it a try?
  - http://zacharyshahan.com/ Zachary Shahan
    
    we can actually make infographics quite easy using visual.ly — just never tried it.
jburt56

Eventually you can put 50kWp on an optimally facing roof so charge time would almost always be under an hour per car at noon.
globi

You’ll also notice that a solar car port (or the roof of your garage) produces easily more electricity than an EV consumes: http://www.eco-way.ch/wp-content/uploads/2011/05/0510-Arean-Solar-1.jpg
- http://zacharyshahan.com/ Zachary Shahan
  
  totally. wind won’t be the only way. just some fun with numbers.