RegGuheert wrote:It's from the link to the article which is same link that I provided for the estimate of 630 kWh the other way fully loaded. I should have linked it in that comment, as well.lorenfb wrote:Where are the data to conclude this, i.e. an energy consumption of at least 300 kWh (over 250 miles) - less than a mile/kWh?
Thanks for the info and link.
Since you have most likely gathered the data relating to an economic analysis of operating costs for an EV semi versus a diesel ICE semi,
exclusive of factors such as maintenance, insurance, energy costs (electricity vs diesel fuel), etc., here are a few questions:
1. What is the generally accepted typical energy usage per mile (miles/gal) for a diesel rig (tractor & typical fully loaded trailer)
traveling at 60mph on a level highway?
2. What is the assumed miles per kWh for the semi in #1, given these components;
a. Rolling Resistance Losses - RR = k * V
b. Drag Losses - DL = k * V^3
c. Energy Conversion Efficiency of the diesel ICE, - assumed to be a little better than a gasoline ICEV (@ about 60%), assume 75% for diesel?
3. What is the assumed miles per kWh for an EV semi assuming RR & DL are the same for a diesel ICE semi traveling under the same
conditions and assuming about +95% energy conversion efficiency for the EV semi?
A simple solution to #3;
1. Assume 38 kWh per gallon of diesel fuel.
2. Assume RR + DL = energy output of diesel = .75 of diesel fuel energy input
3. Then miles/kWh for the EV semi = miles/gal (diesel mileage) X (EV conversion efficiency) / (kWh/gal X diesel conversion efficiency),
or simply MPG (#1) X .95 / (38 X .75)
4. Assuming a diesel ICE under conditions of #1 with an MPG = 5 miles/gal (bad assumption?) then;
EV semi miles/kWh = .167 miles/kWh
5. If one assumes that the diesel is only 50% efficient versus 75%, then the EV semi miles/kWh becomes .5 miles/kWh
Your range number from the quotation is 250/300 or .833 miles/kWh for an unloaded tractor & trailer not necessarily on level
terrain and not necessarily at 60 mph. So what data have you found that realistically compares the two vehicles based on
just efficiencies, exclusive of the key factors; the energy cost differential, maintenance, etc.? I may have missed a post of yours,
so what calculation data, e.g. present cost per kWh for a EV semi, have you been assuming in this thread?
1. Diesel fuel is presently at about $4/gal which amounts to about $.10 / kWh.
2. Unknown weight delta between power train of diesel semi (ICE, gearbox & diff) versus EV semi (battery for same range &
3. Potential loss of cargo capacity delta, i.e. EV battery size delta over ICE power-train.
4. Charging infrastructure and delivery costs per trip.