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I would like just one other point, I belong to a group of people building tiny houses. One of our members is presently in Africa building low costs schools and other buildings with limited solar power.
If BEVs get so common that the scrap yards get flooded with car batteries and the resale value drops like a rock not making them worthwhile to recycle, then he knows people who are willing to pay a few hundred dollars per module to go with their solar systems.
So it becomes - Batteries stay expensive we will recycle them, Batteries become cheap we have lots of buyers around the world for them.
The one place they will not end up in, is in land fills.
I just got back from Chile talking to your competition. Copper, Lithium, Cobalt etc mining. Massive expansion and recovery efficiency improvement plans. It's going to be interesting.
Re. calcs I will do another set for three different vehicles (different mass, CD, frontal area). The physics physics/math is fine I just want to use less extreme inputs - i'll post the numbers later today when I get a chance.
Chile, nice place hope you had a good trip - been there many times and enjoyed plenty of good reds.
Originally Posted by earl pottinger
I would like just one other point, I belong to a group of people building tiny houses. One of our members is presently in Africa building low costs schools and other buildings with limited solar power.)
Excellent, well Earl I tried your recommendation wrt my garage and my cars - clearly my tolerance for CO is pretty high. Now, I grew up in North Africa and on and off over 35 years I have worked through Southern and south central Africa - in that time I have set up medical facilities, schools, provided access to free condoms and antimalarials, instigated vaccination programs and even created jobs and employment. In that time I learned to listen, and by that I mean to listen to what people wanted and needed and also ask the question "what do you need" - no one ever asked for solar panels and cast off batteries.
When you go to countries less fortunate than our own its pays to listen to what is required rather than dictate or assume what is required.
Perhaps you should go there - why don't you start with this question, how long will you have to work in order to buy the (non-existent) 35k USD Model 3.
We don't need the entire world to move to EV's right away - steady progress in major developed nations will represent dramatic improvements in emissions and reduction in fossil fuel consumption - ICE cars are going to be with us for quite some time and they have applications I don't foresee EV's replacing anytime soon - that doesn't mean that EV's aren't useful , they just aren't useful/optimized for certain types of applications, just like ICE's aren't optimized for certain types of applications.
Telsa has sold nearly 350,000 EV's world wide (may be more) - each one of those EV's if driven 13,000 miles a year represents a reduction of at least 27 barrels of oil a year…
27 barrels of oil less per-year per car = 9.45 million fewer barrels of oil burnt just for Tesla's - per year
a mix of EV's doing what they do best (commuter congestion developed world) and leaving the ICE's in the areas where the infrastructure requirements for EV aren't quite there yet…and ICE's are a more appropriate choice - this isn't an all or nothing game - we can have both types of personal transportation - but we need to be open to more EV and less ICE - most people in the developed world don't need all the features of an ICE, an EV would fill 99% of their usage and have a dramatically lower impact.
We don't need the entire world to move to EV's right away.
Boom, agreed there needs to be transition at many levels from power mix to power generation, transmission networks, distribution networks down to charging infrastructure.
However, for this to occur, have impact and provide lasting change requires long term planning - not ad hoc measures. This requires serious, measured debate focussed on developing actionable plans.
The table above shows sustaining HP - e.g. the amount of HP required to sustain a car at 70 MPH. The energy number is the amount of energy required for the vehicle to travel at 70MPH for 1 hour (under ideal circumstances). The most contentious variable is the coefficient of rolling resistance (all vehicles are in the accepted range of ~ 0.005 to 0.015 - and adjusted for size - for perspective under inflated tires can add 25% to the CRR).
A model developed by AEMO (market regulator) - this is consistent with other expert views in that the take up rate for EVs will be much slower and ICE will play a considerable role into the future. The model is the neutral (mid-range model) and is based on a range of assumptions including vehicle cost, through infrastructure and and home para infrastructure costs. this model is consistent with predictions by Bloomberg, other regulators and indeed inline with BMWs planning (50% EVs by 2050).
Most of the developed world is in this position - the strategic thinkers and doers are kicking in e.g. solve the problems is the correct order
(1) Power mix - (generation type and mix relative to environmental and resource location factors - no room for NGOs at the table, no relevant competency - not solution orientated and politically motivated)
(2) transmission and distribution network upgrades
(3) planning for charging infrastructure
(4) progressive introduction of cost effective home "renewable" systems
(5) progressive introduction of cost effective and efficient EVs
(6) continued use of specialist ice vehicles and the phasing out of commuter ICE over time (.25 yrs)
(7) continued use of ICE in remote locations and those challenged by infrastructure and economics.
The table above shows sustaining HP - e.g. the amount of HP required to sustain a car at 70 MPH. The energy number is the amount of energy required for the vehicle to travel at 70MPH for 1 hour (under ideal circumstances). The most contentious variable is the coefficient of rolling resistance (all vehicles are in the accepted range of ~ 0.005 to 0.015 - and adjusted for size - for perspective under inflated tires can add 25% to the CRR).
You came up with this yourself? I assume you miss-labeled and meant "Model 3" where you have "Model X", also check your CRR vs weight trend.
Overall I think you're beginning to see the big picture: other factors dominate over the EV weight difference. If you set up a head to head of the Model 3 vs competitors like the Audi A4 (3630 lbs) and BMW 320i (3690 lbs) this will become very obvious (especially as there is a less than 7% weight difference and by extension rolling resistance difference between the cars). The upshot is that controlled highway speed tests show the Audi and BMW at 39 and 40 MPG respectively vs 123 MPGe for the Model 3 (city with acceleration included the difference is far greater: 17, 18 and 136). Most of that is explained by power-train efficiency, but not all...
The trouble with this type of comparison is of course that Tesla has made a number of compromises specific to the Model 3 that do not apply to all EVs generally. Even with rudimentary numbers, however, it's fairly easy to see that the reduction in drag (14% in the apples to apples example of the Fiat 500e vs the gasoline powered 500) more than trumps the increase in rolling resistance due to additional weight.
Correct, it should be model 3 instead of model x - that is a typo.
Its a pretty fair comparison - there is no fudging - rolling resistance is a problem in that heavy cars impact on sidewalls. The Crr ranges are well within acceptable limits and at the level of variation achieved by underinflation.
Note there are plenty of vehicles coming out with far lower CDs e.g. MB A and C class down to 0.22. The point being all car manufacturers are improving products.
Nothing wrong with the physics or maths Pete. It's pretty simple at the end of the day smaller cars are better for the environment, they use less raw materials and require less energy to go from A to B. E.g. Model 3 Vs Model S comparison above.
The table is my own work, I might to do another one with the latest crop of light weight low CD vehicles relative to the Tesla range - I'm pretty sure you know the x is problematical due to its large frontal area, the S is on the edge whereas the 3 is looking pretty good.
but you have to factor the conversation rate to achieve the desired MJ to move the car - smaller cars require less energy to move - but ICE cars covert energy with 20'ish% efficiency, and EV's convert it with 90% efficiency - so the input energy required for the ICE car is far higher, even when it's uses less energy to actually move
3000 lbs ICE car from your table requires 52.3 MJ by your table - for an ICE car at 22% efficiency requires (X * .22 = 52.3) 52.3 / .22 = 237.72 MJ of "fuel" to achieve 52.3 MJ "output" to cruise at 70 mph
the Model S requires 62.5 MJ - but is 90% efficient with the power that's in the battery - so to cruise the same speed at the same distance requires ( X * .9 = 62.5) or 62.5 / .9 = 69.44 MJ of electricity - far less power input than the ICE car - even though the ICE car is lighter and needs less power to move - it requires more input energy to move the same distance at the same speed than the heavier car.
so the ICE car consumes 237.72 MJ of power
the heavy EV car consumes 69.44 MJ of power.
which car uses less energy?
now we can take the same amount of fuel used for the gas car (237.72 MJ) and deliver it to a 40% efficient power plant and that will yield 95.088 MJ of power delivered to the electric grid - the grid is 93% efficient - so that's 92.23536 MJ delivered to someone's home - the EV chargers are about 93% efficient at getting power into the battery so that's 85.7788 MJ delivered to the battery for the _SAME_ amount of fuel burnt at the power plant.
the EV requires 69.44 MJ for this little example - so 88.7788 / 69.44 = 1.23 time further the heavier EV can go on the same amount of input fuel burnt at a power plant and delivered to the EV
so given the exercise above at 70 mph and an input budget of 237.72 MJ of power
the ICE car which is lighter goes 70 miles (70 mph for 1 hour)
the EV car which is heavier goes 1.23 times further on the same amount of input fuel run through the power grid and delivered to the battery
70 * 1.23 = 86 miles driven at 70 mph for 1.23 hours.
same amount of fossil fuel burned = one car goes 70 miles, the other car goes 86 miles - so the heavier car is more efficient vs. the lighter car - and if we make the EV car the same weight as the ICE car then it gets even better - enter the Tesla Model 3…similar weight class as the ICE car, 90% efficient
the Model 3 requires 49.4 MJ to go 70 mph for 1 hour - so it's input power requirement is 49.4 / .9 = 54.888 MJ to go 70 miles at 70 mph
we know the same amount of fuel from the power plant yields 88.7788 MJ in the battery
so 88.7788 / 54.88 = 1.617 times further at 70 mph for the same amount of fuel or 113 miles driven @ 70 mph for the Model 3 class EV vs. the 3000 lbs ICE car @ 70 miles driven.
Last edited by daveo4porsche; 10-22-2018 at 09:58 PM.
lighter is always better - EV and ICE< but heavy EV's are still way better than than inefficient ICE's - 70 % natural gas is going to be way better than any ICE car - Natural Gas power plants are 50-60% efficient - and coal is shrinking - western's US energy grid is 42% natural gas, 3% coal, and the rest is renewables - wanna do that comparison.
this Forbes article did that comparison (coal power) and EV's still come out ahead - https://www.forbes.com/sites/energyi.../#7ea5524071f8 - I concur with their math - given the horrible efficiencies of an ICE motor from an emissions point of view EV's still win even when your power is from coal…but again coal is shrinking not growing in the areas of the world that are likely to be buying EV's.
the heavier EV is still better for the environment than the lighter ICE car…the total power requirements are dramatically smaller, and EV's are getting lighter not heavier, and will overtake ICE cars - the new mid-range Model 3 is actually lighter than a BMW 3 series and still 90% efficient drive train.
but yeah I'll take a lighter EV any day it will make them even better - but EV's are sooooo much more efficient that even if ICE's are lighter their horrible conversion rate makes it way better to burn the fuel in a power plant than in a personal ICE motor.
there is no fudging - rolling resistance is a problem in that heavy cars impact on sidewalls.
That would be true if the heavier weight was not counteracted by higher inflation pressure, which is typical off all heavier cars and certainly true of Tesla (the Model 3 is at 42 psi). It's not hard to calculate the area needed to support the car's weight at a given air pressure, then back out tire deflection from that. Search the literature, if you're honest with yourself I think you'll agree your quoted trend is wrong.
Originally Posted by groundhog
The point being all car manufacturers are improving products.
Sure. Just realize that the lack of needing to route additional air through the car for cooling air likely gives EVs a fundamental advantage rather than a disadvantage as you were earlier thinking.
Originally Posted by groundhog
at the end of the day smaller cars are better for the environment, they use less raw materials and require less energy to go from A to B.
That I agree with (within reason). Small is good, and a VW XL1 with lower cost materials would be pretty ideal if you don't need space, etc. Obsessive weight chasing often backfires, however, especially when you take the ICE out of the equation, and hence don't get the efficiency benefit of a smaller engine to offset the higher materials costs that lighter weight requires. Even with the downsizing benefit weight reduction often can't justify its high price (as seen in the Audi A2 3.0L's low production volumes).
Again I'm not quite sure what your argument is. Are you saying that there are better paths to high efficiency than EVs through downsizing and efficient ICE cars? Or what are you proposing, both for the near luxury class and otherwise? I mean at the end of the day electrically assisted bicycles are really good, that's obvious...
even using ground's own number the "heavy" Model S is still 1.23 times more efficient than the "lighter" ICE car - and uses less power to go the same distance - basically if you're comparing 90% efficient drive trains to 2x% efficient drive trains you can commit a lot sin's in the 90% efficiency drive train and still be better overall than and ICE car - I think the number pretty conclusively show that
now if factor in say being powered by a 60% efficient natural gas powerplant where natural gas is way cleaner burning than gasoline - then it's an even bigger win, and then move to renewables that are true zero emission (as in the case in a lot of the developed world) and it gets even better...
even heavier EV's are less impact per-mile than a lighter ICE car - the numbers are pretty clear - and the mountain of research backs that up.
I have a book published in 1996 which chronicled the development of GMs EV1. ("The Car That Could", by Michael Shnayerson) In it, even in 1996 some anti-EV folks were pointing out the "runs on coal" argument. The argument was refuted then. And in the intervening 22 years, the grid of today has become far cleaner than the grid of 1996. Here in California there is zero use of coal to generate electricity.
@whiz944 love you bro - and you and I are normal on the same side
but California's own numbers show 4.13% of our grid is still coal as of 2017 - so close, but we too still have that little black energy dense fossil fuel in our midst…
@whiz944 love you bro - and you and I are normal on the same side
but California's own numbers show 4.13% of our grid is still coal as of 2017 - so close, but we too still have that little black energy dense fossil fuel in our midst…
That tiny bit of in-state generation is from a co-generation plant at some mine out in the middle of the Mojave desert. It barely blips the dial. Yes there is still some out-of-state coal generation that gets fed by the grid into CA. But it is also disappearing.
Again I'm not quite sure what your argument is. Are you saying that there are better paths to high efficiency than EVs through downsizing and efficient ICE cars? Or what are you proposing, both for the near luxury class and otherwise? I mean at the end of the day electrically assisted bicycles are really good, that's obvious...
I saw the big picture a long time ago.........
Simply pointing out that smaller is better for the environment whether it be ICE or EV . e.g. a smaller ICE is better for the environment than a bigger ICE likewise a smaller EV is better than a larger EV.
Pete as you and I both understand - the problem that needs to be fixed is a global one and that means a broad view and a broad church.
Also I wasn't saying that EVs had a CD problem - I was saying that large cars have a large frontal area which can be compounded by a poor CD (if the design is poor, the comment was drive train neutral). Likewise the next generation of ICE cars are coming out with substantially lowered CDs ~ 0.22 e.g MB A and C class.
As is clear from a number of posts here, many EV owners are driven from a political perspective - that doesn't interest me. An effective solution is what interests me and that has to start with generation mix - this is different for different continents, latitudes and sovereign economic profiles. Optimise the generation mix and infrastructure and the rest is easy.
Keep in mind, the current price of a Tesla in Australia ranges from 100k (2nd hand P70) to 270k (new Model X P100D) and fully effective solar array plus batteries is another 25k - yes thats right. Thats a hard sell (and from a quality and finish perspective a joke that few will pay for).
I note California is the second largest consumer of energy in the US and 34% of this comes from natural gas (CH4 + 2O2 = CO2 + 2H2O - 1 mole of methane produce 1 mole of CO2) and 4% from coal. So 38% from fossil fuel. California on its own accounts for about 1.0 to 1.5% of global emissions e.g. similar to the whole continent of Australia (which contributes significantly to the feeding of SE Asia).
Dave, GDI Engine small car (1/.35 * 39.7 = ~) 114MJ Vs Model S (11/0.9*1/0.72*62.5) on California energy mix 97MJ
So the model 3 makes sense, the S barely so and the X doesn't (it has a big frontal area) unless you have access to a significant component of renewables or you have home solar and full battery back up.
Note Morgan Stanley recently came out with a report (and I'll try and dig it up) that pointed out the amount of energy required to support the predicted uptake of EVs - they state something along the lines of most reports for the western world under estimate the energy/ generation requirement - typically reported as about 8% to 12% of current load. Their finding is this should be generally upscaled to at least 25% - a very big difference. This is something I tend to agree with - humans take the path of least resistance and will plug into whatever's easiest.
Again the solution is the generation mix, cost effective home solar where permissible and cost effective battery storage (pretty much everywhere e.g. store wind from grid during sleep hours). .
10-21-2018, 03:50 PM
