View Single Post
Old 12-22-2010, 06:55 PM   #71 (permalink)
IamIan
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 692
Thanks: 371
Thanked 227 Times in 140 Posts
Quote:
Originally Posted by mnmarcus View Post
Me too! But I'm equally suspicious of ;

"Given the much higher ~90%+ Efficiency of modern electric drive systems ... and given the much much broader range of higher operating efficiency ... efficiency less effected by cold ... by load ... etc."

and

"This makes the BEV about ~300% more energy efficient compared to the ICE , at the vehicle level... or for a given amount of energy , the BEV I would generally expect to travel about ~3x as far.BEVs that end up weighing more will have more rolling resistance ... which is linearly related to weight ... so in order to counter the ~300% vehicle level energy efficiency ... the BEV weight would have to increase by close to ~300% ... which even lead sleds don't get that much heavier."
Well sense I think these two are from me .. I can offer a bit more for these.

The first one ... I am describing the efficiency of the electric drive system itself ( electric motor , controller , battery ) have much better operating energy efficiencies than ICE's do ... and the efficiencies of ICEs vary much more as conditions change like RPMs, load, temperature, etc... this is easily verifiable from a variety of sources... I can dig up some for you if needed... for some specific comparisons.

Although it is only referring to the drive system efficiency ... and not the source of energy ... but if you want to talk about energy sources ... great ... all fossil fuels are horribly inefficient forms of using solar energy... and I do mean horribly inefficient.

- - - - - -

The second one at the vehicle level BEV are massively more energy efficient than ICEs... This seems to greatly agree with the studies you posted

Your #1>
BEV 88%
ICE 15%
at the vehicle level the BEV is ~5.8x more efficient ... or ~488% more efficient.

Your #2>
BEV 529.5 miles per Million BTUs
ICE 182.5 miles per million BTUs
at the vehicle level the BEV is ~2.9x more efficient ... or ~190% more efficient.

Your #3>
BEV 90% efficient
ICE 20% efficient
at the vehicle level the BEV is ~4.5x more efficient ... or ~350% more efficient.

Quote:
Originally Posted by mnmarcus View Post
But we get numbers from studies and (often in my case) searching the web. Should we just throw out the "bad" and "dirty" pro-gasoline info and ignore anything negative about "good" "clean" electricity?
excellent point ... and I 100% agree ... we should look fairly at either one or all other alternative options... but there are different ways to look at it ... and we do not all have the same perspectives / priorities.

Liquid hydrocarbons be it gasoline, diesel, bio-diesel, ethanol , etc... all have very good energy density per unit volume ... that is a significant benefit for those fuel options... that energy density allows for the significantly less efficient drive train to still be viable... it allows it to refuel quickly ... it allows for longer ranges from a given volume of energy/fuel storage... in short I think the vast majority of the benefits come from the volumetric energy density benefit.

But we should also be honest about the superior energy efficiencies of the BEV option ... even when well to wheels are counted ... and if you do a complete life cycle of the energy source ... it seems RE BEV always dominate the energy efficiency contests.

- - - - - -

I would also say cost effectiveness or MPGe based on cost is a different issue ... and it is important... and I think that is currently perhaps the weakest case BEVs have.

BEVs have low fueling costs ... but at present the initial up front costs are much higher ... thus on a cost basis ... ICEs still have a very strong case to make... and likely will for many years or decades to come.

  Reply With Quote