Electric cars 'pose environmental threat'

A recent study by MIT and a Norwegian University, found that if one factors in the energy cost and carbon production of extracting the minerals necessary for making batteries, refining them, and manufacturing them into batteries, the carbon production exceeds that saved by use of the batteries in electric vehicles.

Bottom line: electric vehicles are responsible for more carbon than fossil fueled vehicles!

Slick
"LIFE CYCLE COST" As I've been screaming at the top of my lungs for 40 years. It has only improved SLIGHTLY in all that time!

Without subsidies that YOU AND I pay for, they would have been long gone.
 
A simple way to reduce the amount of embedded energy in vehicular traffic would be to rebuild something old rather than buy something new. Hmmm... Nortons huh...
 
I still don't know why this isn't explored more, is it a lack of lobbying or too much investment gone to electric vehicles already.


 
I still don't know why this isn't explored more, is it a lack of lobbying or too much investment gone to electric vehicles already.

Sounds great. What about the energy consumption required to produce 1 litre (~0.78 kg) of synthetic gasoline? The energy content of that gasoline is ~43.5 MJ/kg.
The interview failed to address this issue.

It is possible to produce synthetic fuel in a number of ways, extracting carbon from atmospheric CO2 is just one. In a paper at Stanford University dated 2012, the autor claims the energy efficiency of the process to be 16% maximum, resulting in a cost ratio vs. electricity of 1:6, i.e., if 1 kWh_el costs $1.00, the equivalent 1 kWh_synthfuel will cost $6.00 .

http://large.stanford.edu/courses/2012/ph240/jorna1/

These processes are not new. Some developments may have taken place since 2012, but we can't get away from the fact that producing synthetic fuels can't compete with "raw" electricity, and the cost of synthetic fuel will likely not be accepted by the buying public given cheaper alternatives.

Gents, like it or not, but we are seeing a shift driven by sound economic thinking, competition, freedom of thought and environmental concerns. Agreed, some solutions are short-sighted as yet, but in the long run we all have to find sustainable ways of producing our goods.

-Knut
 
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Energy density.

Tesla battery pack is only around 150 WH per kg, versus gasoline’s 12,000 WH per kg. As the gasoline is consumed the tank gets lighter, the battery does not get lighter so the density needs to be 24,000 WH per kg to be equivalent. In the same way wind power is subject to Betz law , ie there is a top limit to efficiency of transfer of wind energy to power, battery density will be limited by the max power of electrons, so peak density will be 850 WH per kg.

So Electric cars powered by batteries are a dead end.
 
Regardless of where the energy comes from, renewable, green or otherwise, we now liberate energy into our biisphere that is an appreciable percentage of that falling on the planet from the sun. A smarter society might run a so-called hydrogen economy, where solar energy is used to release hydrogen from water by thermal or electrolytic processes then combust this when and where required. Net heat dumped into the environment is just that associated with the inefficiencies.
Another area of interest is what's known as "thermal diodes" or "Maxwell's zombies". It seems there is a loophole in the laws of thermodynamics.
We are smart monkeys and there is always hope.
 
Acotrel:

Thr UK electricity agency built a double dam scheme like you describe back in the mid-1950s. It's in Wales somewhere, but I can't remember where. I assume it's still operational.
 
Energy density.
< ...>
So Electric cars powered by batteries are a dead end.

Not quite. In the end we want to produce torque, generating a motion, right?
Electric energy stored in batteries may be converted into wheel torque by an efficiency factor of 0.9 .
The best NiCad batteries are able to store 265 Wh/kg. Usable specific energy is therefore 239 Wh/kg. Battery technology is still in its infancies and Bosch company predicts a storage capacity of a new generation of batteries at 500 Wh/kg by 2020 (usable specific energy 450 Wh/kg).
On the other hand, thermal energy stored in gasoline (fossile or synthetic) may be converted into wheel torque by an efficiency factor of 0.2 . Hence, the usable energy density of gasoline is 12000 * 0.2 = 2400 Wh/kg.

Yes, there is still a gap but it's closing. Considering the simplified propulsion design of an electric vehicle, the gap is actually smaller than shown here, maybe 700 Wh/kg usable energy by 2021. Anyway, isn't energy density per volume more appropriate than per weight?

-Knut
 
The emporers new clothing scenario is only true of most electric car usage, because people are charging their cars with electricity off of a commercial electrical grid. I was at a guy's house for a job yesterday and he has his own solar panel array on his roof facing south. His net power draw for the year is into the negative, so the power company actually pays him some small amount of money every year for his power generation.

He's thinking of getting an electric car, because it would act as both a storage cell for his extra generated energy and supplant his use of gasoline to travel locally, so there is a viable and simple usage model were electric cars make sense and contribute zero carbon emmisions to the atmosphere during it's usage.

Granted that electric cars are not good for traveling long distance because the batteries take a long time to charge, unlike refilling a car's fuel tank with gasoline, which takes only minutes, but to generate your own solar power to charge an electric car for local traveling seems to me the most carbon friendly vehicular transportation method on the planet to date. Granted that there are energy costs to making electric cars and solar panels, but I wonder how they compare to the energy costs of making internal combustion engines...

I am anything but a politically correct liberal, so don't accuse me of buying into some progressive philosophy. I am a scientific person and it seems there is a viable model for electric car use that is extremely eco-friendly for local usage. It may not replace internal combustion engines for all travel purposes, but certainly for local daily traveling from work to home, there should be some carbon emmissions advantage.
 
To me a hydrogen and electric powered hybrid would make more sense, but even to get hydrogen, you need electricity. And hydrogen probably cannot be stored safely, like acetylene.
 
acotrel said:
... hydrogen probably cannot be stored safely, like acetylene.
It certainly can, the trick is storing it safely at high pressures and densities efficiently. There is a significant energy cost in compressing hydrogen - up to 20% of the energy content. Hydrogen can also be stored as hydrides; reversible hydrogen compounds, typically Metal Hydrides, at moderate pressures and low temperatures. A hydrogen economy is possible with existing technologies and ongoing research is making this ever more a reality.
 
If it needs a subsidy you have to be skeptical. Problem is there are subsidies all over. Even gasoline is subsidized . . . before it’s taxed.

Cronyism is everywhere; especially in “green” tech
 
Not quite. In the end we want to produce torque, generating a motion, right?
Electric energy stored in batteries may be converted into wheel torque by an efficiency factor of 0.9 .
The best NiCad batteries are able to store 265 Wh/kg. Usable specific energy is therefore 239 Wh/kg. Battery technology is still in its infancies and Bosch company predicts a storage capacity of a new generation of batteries at 500 Wh/kg by 2020 (usable specific energy 450 Wh/kg).
On the other hand, thermal energy stored in gasoline (fossile or synthetic) may be converted into wheel torque by an efficiency factor of 0.2 . Hence, the usable energy density of gasoline is 12000 * 0.2 = 2400 Wh/kg.

Yes, there is still a gap but it's closing. Considering the simplified propulsion design of an electric vehicle, the gap is actually smaller than shown here, maybe 700 Wh/kg usable energy by 2021. Anyway, isn't energy density per volume more appropriate than per weight?

-Knut

Knut:

Your analysis is correct, but you did not take it far enough.

True, the conversion factor of stored electrical energy to torque is about 0.9, but one must factor in the source of the electrical energy. The energy comes from the power grid which has a thermal efficiency of about 0.45. Then, the overall factor is 0.45 x 0.9 = 0.4. Modern engines are about 0.35, and with increases in the efficiency of power transmission to the drive wheels, petrol power is nearly as efficient as electric power.

Thermodynamically, it all comes down to the fact that stationary power plants are more efficient than mobile ones, and so electric vehicles will enjoy a slight edge over petrol power. But then, there is that factor of energy cost to produce, and ultimately recycle batteries ......

Slick
 
Hi Slick, the recent discussion was about energy density for propulsion, i.e., topics confined to the vehicle.

In response to your comment, thermal efficiency varies greatly with how the power grid is supplied. Hydropower plants, solar, wind and ocean wave farms have a "thermal" efficiency of 1.0 (no exhaust). Nuclear powerplants need cooling but they do not contribute to greenhouse emissions either, thus have a corresponding thermal efficiency of 1.0 . Same goes with geothermal powerplants.

Thermal efficency of coal burning powerplants can be greatly increased by designing them for heat-power (i.e., utilising "waste" heat for heating buildings , agriculture and process industries, which will nullify emissions with those recipients). This is quite common in Europe but probably less so in North America. Catching CO2 is viable only with large stationary powerplants.

-Knut
 
Gonna get flak from more than a few here I expect, but here is a well researched rebuke on this thread's title:

 
Most cars which run on LPG are dual fuel. Why couldn't hydrogen and petrol be used in the same way in an electric powered hybrid ? If you got stuck, you could just sith there for a time with the engine running on hydrogen or petrol while charging up the batteries. Then drive on.
 
When I renewed my house and contents this year the nice lady asked me if I had solar panels on my roof. I told
her no, but asked why the insurance company wanted to know. She said if my house was on fire the fire brigade
would not be able to use water ! Presumably as water and electricity do not mix well.
I've no idea if this is true or wide spread?
 
Electric vehicles are far from a perfect solution to poor air quality, but try to remember the first gasoline-powered vehicles ran less than 15 mph and were required to have a flagman walking ahead so as to warn horse-powered vehicles (and individual horses) of it's approach.

Electrics are in their infancy now because they were poo-pooed out of existence by their (relative) inefficiencies when compared to fuel-burners. The "dead ends" and "it will never work"s are just echoes of things that have been said before about present technologies. All the major vehicle manufacturers and all the oil companies are involved in r&d for electric vehicles. I don't think they'll give up tomorrow due to skepticism over their viability.

There's money to be made now and even more when battery technology takes it's next leap, or someone invents a viable hydrogen-electric hybrid or figures out how to miniaturize fusion reactors. It's happening and while it's easy to sit back and be cynical, just as it has been on climate change, the "conventional wisdom" is changing nearly as fast as the tech.

I always use the trash analogy; If trash were valuable, nobody would toss it out the window of their cars. Make packaging viably recyclable and profitable and you solve the trash problem. If someone can make a profit doing something currently thought to be impossible, it will likely happen over time. Electric vehicles are happening, cynicism not withstanding.
 
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