We don't need EVs because it's the cheapest or most efficient means of powering personal transportation, we need EVs because they would mean massive demand destruction basically solving peak oil! We need to keep enough oil supply for farming, freight, plastics etc, not wasted driving around.
In the short to medium term who cares how much extra coal gets burnt? Not that it would be all that much, since any grid is massively under-utilized at night, which is exactly when EVs would be charged.
PeakOil is You
THE Power Grid Thread (merged)
Re: Power Grid Limits Potential of Renewable Energy
by vilemerchant » Thu 28 Aug 2008, 15:24:28
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Re: Power Grid Limits Potential of Renewable Energy
by lper100km » Thu 28 Aug 2008, 15:27:29
$this->bbcode_second_pass_quote('yesplease', 'T')he assumption for efficiency of delivering power to the wheels is a bit more than twice the average lper100km, at least in the US. Something like a hybrid may see ~25%+ BTE, but the average vehicle is somewhere around 15%.
Unless I am mistaking your comment, I noted that the ICE auto power to the wheels efficiency is 14%, so I think we are agreeing on that point. The EV efficiency is much higher.
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Re: Power Grid Limits Potential of Renewable Energy
by yesplease » Thu 28 Aug 2008, 15:51:43
You probably did IIRC, but in the above comparison it seems you used 25% instead, unless of course I'm reading it incorrectly.$this->bbcode_second_pass_quote('lper100km', 'E')fficiency in delivering energy to the road wheels: 25%
Last edited by yesplease on Thu 28 Aug 2008, 16:56:58, edited 1 time in total.
$this->bbcode_second_pass_quote('Professor Membrane', ' ')Not now son, I'm making ... TOAST!
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Re: Power Grid Limits Potential of Renewable Energy
by lper100km » Thu 28 Aug 2008, 16:23:22
Oh OK Yes, I calculated the overall efficiency at 14% Maybe I'm being overly generous in setting the drive train efficiency at 25%. If you take ICE power to the wheels at as low as 15% the overall energy efficiency reduces to 8.5% nominally. For auto use, we are wasting 91.5% of the oil energy that is pumped from the ground!! It's criminal.
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Re: Power Grid Limits Potential of Renewable Energy
by JRP3 » Thu 28 Aug 2008, 18:19:28
Your charging efficiency number is off as well. Flooded lead comes in around 70%, sealed lead AGM types even higher above 90%
Charging
Lithium even better near 99%
Lithium
These numbers and the other changes yesplease pointed out push your calculations even further in favor of EV's and further points out the irrationality of wakeupman's rant.
Charging
Lithium even better near 99%
Lithium
These numbers and the other changes yesplease pointed out push your calculations even further in favor of EV's and further points out the irrationality of wakeupman's rant.
Blogging about EV's
http://ephase.blogspot.com/
Building the AMPhibian
http://amp-phibian.blogspot.com/
http://www.diyelectriccar.com/forums/
http://ephase.blogspot.com/
Building the AMPhibian
http://amp-phibian.blogspot.com/
http://www.diyelectriccar.com/forums/
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Re: Power Grid Limits Potential of Renewable Energy
by lper100km » Thu 28 Aug 2008, 20:33:08
As I understand it, there are two components to charging. The charger itself is between 70 - 75 % efficient and the battery charging performance can be as you have stated.
I would certainly like to see the electrical systems become really efficient. There is no question that they offer the greatest hope, but storage for use on demand represents a major and difficult challenge.
I would certainly like to see the electrical systems become really efficient. There is no question that they offer the greatest hope, but storage for use on demand represents a major and difficult challenge.
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Re: Power Grid Limits Potential of Renewable Energy
by Frank » Thu 28 Aug 2008, 21:07:21
I think that battery charger efficiency can be all over the board, depending on quality of components chosen.
One strategy for charging lead-acid (that I use a fair amount) is to charge only to the gassing or Absorption voltage (i.e. about 14.4 volts for a 12 volt battery) then shut off the charger. This typically works more efficiently as energy isn't used to "bubble" the electrolyte. This returns 80-90% of capacity to the battery, which is enough, particularly in warmer weather when lead-acid works best. Lead-acid batteries need to be completely charged i.e. sit at constant voltage at least once a week minimum (approx.) but this is a bit less efficient.
ICE's are constrained by Carnot. Fossil fuels are so energy/power dense that we've let vehicles get way too big and heavy and haven't spent much attention on innovative design. EV's demand cleverness and I think we'll see a lot of new, great ideas in the next few years.
One strategy for charging lead-acid (that I use a fair amount) is to charge only to the gassing or Absorption voltage (i.e. about 14.4 volts for a 12 volt battery) then shut off the charger. This typically works more efficiently as energy isn't used to "bubble" the electrolyte. This returns 80-90% of capacity to the battery, which is enough, particularly in warmer weather when lead-acid works best. Lead-acid batteries need to be completely charged i.e. sit at constant voltage at least once a week minimum (approx.) but this is a bit less efficient.
ICE's are constrained by Carnot. Fossil fuels are so energy/power dense that we've let vehicles get way too big and heavy and haven't spent much attention on innovative design. EV's demand cleverness and I think we'll see a lot of new, great ideas in the next few years.
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Re: Power Grid Limits Potential of Renewable Energy
by yesplease » Thu 28 Aug 2008, 21:15:30
According to the DOE, after taking into account the charging/discharging efficiency of NiMH batteries, the charger efficiency was ~85%. Supposedly the charging efficiency of the AC-150 is 90%+, which is supported by the manufacturer although it can drop to 50% w/ 110V and the lowest charging current at around ~200W.
Last edited by yesplease on Thu 28 Aug 2008, 22:14:28, edited 1 time in total.
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Well lets see... The water will still run, the toilet will still flush, the wood stove and furnace will still heat. I can get all the hot water I need off the wood furnace with a days plumbing changes. I will lose the freezers and their contents assuming there is no fuel for a back up generator. Have to build an ice house but the first summer would be a pain. I have several hundred books including a set of encyclopedia and can walk the five miles to the library. While there I could drop in at the local restaurant anf gossip with the old bucks. Their cliental might be differnt and their menue would change if they were off grid. I might hear some new points of view. At sundown light a candle or go to bed. After a ten mile walk perhaps the later. Life might actually be better up to the point that I have to go to the health center and need an X ray.
