Just figured I'd throw my 2 bits in... some of which has been touched on a bit in some previous posts.
skip it ... or get comfy.
- - - - - - - - -
MPGe.
The way I see it there are 3 main methods ... each of which has 3 sub-methods.
The 3 main methods are:
#1> Vehicle level comparison ( Pump or outlet to wheels )
#2> Complete cycle ( From raw source materials and initial energy sources to material disposal )
#3> Partial cycle ( include more than the pump / outlet , but don't include the whole cycle )
Each of which has 3 sub-methods:
#A> $ Cost comparison
#B> Energy comparison
#C> Environmental Impact comparison
- - - - - - - - - - -
This gives us at least 9 distinct methods of determining MPGe ... and virtually unlimited methods to mix and match different scales of each if we try and combine them.
- - - - - - - - - - -
My personal preferences in order:
#1> Energy comparison
#2> Environmental Impact comparison
#3> Cost Comparison
My personal preferences of main types in order:
#1> Complete cycle
#2> Vehicle level
#3> Partial cycle
- - - - - - - - - - - -
My 2 bits Complete cycle Energy comparison:
For any 'complete' cycle ... My first question is about the initial energy source for the fuel.
Fossil fuels are just a very inefficient method of converting solar energy ... Photosynthesis is less efficient than modern day photovoltaic ... and only a tiny tiny fraction of that energy ends up being converted into fossil fuels ... which then need to be extracted % loss ... transported % loss ... refined % loss ... before they are used in a ICE that is almost never even as high as ~50% efficient.
Compared to converting that same initial solar energy source into electrical energy ... transporting it ... battery cycle ... modern efficient electronics ... modern efficient electric motors ... the RE powered BEV beats the crap out of any fossil fuel option ... I would estimate well over ~300 to 1 advantage for the RE powered BEV.
But with enough data a specific vehicle could be calculated.
- - - - - - - - - - -
My 2 bits Vehicle level Energy comparison:
Given the average ICE efficiency of ~30% ... with peaks as high as ~50% ... and lows as low in the single digits %.
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.
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.
Of course individual vehicles can be measured ... by the energy content of the fuel they use compared to the average distance they travel with that amount of fuel energy... the low efficiency of ICEs pretty much destroys them in this type of comparison.
- - - - - - - - - -
Although partial cycles are not a preference of mine ... I do recognize allot of people usually ignore all the losses it took to produce the fossil fuel in the first place.
Even on that level I would suspect a BEV would still come out ahead on a energy efficiency basis.
Short version:
I suspect : A Gasoline fueled power plant would most likely move BEVs ... further per gallon consumed ... than multiple ICE fueled vehicles with the same amount of gasoline.
The massive variation of ICE efficiencies is a killer to that platform ... a stationary centrally located power plant no longer has to worry much about size ... or weight ... a 0.1% efficiency improvement that costs 2 tons of equipment , is usually worth doing.
This means that the more efficient centrally located power generation system will be likely to operate at close to double the energy efficiency of the mobile ICE that has so many other compromises due to weight , size, efficiency fluctuations , etc.... if a co-generation plant ... it might be as high as 3x as efficient.
I suspect , losses in electrical transportation are less per unit energy than the losses of gasoline transportation ... meaning the trucks that drive the gasoline around the country from the refineries ... are far less efficient than the electrical grid... per mile / per unit of energy.
In short ... there are very good reasons we do not run generators at each of our homes ... and have them all powered by gasoline deliveries ... the same is true for why a more efficient centrally located power plant would make better use of the same fuel.
The added bonus ... is that the centrally located power plant , would not need as much refining losses of the initial fossil fuel.
with enough data this could also be calculated for a specific vehicle , and power plant.