  There has been considerable interest in the electrification of freight
transport, particularly heavy-duty trucks to downscale the greenhouse-gas (GHG)
emissions from the transportation sector. However, the economic competitiveness
of electric semi-trucks is uncertain as there are substantial additional
initial costs associated with the large battery packs required. In this work,
we analyze the trade-off between the initial investment and the operating cost
for realistic usage scenarios to compare a fleet of electric semi-trucks with a
range of 500 miles with a fleet of diesel trucks. For the baseline case with
30% of fleet requiring battery pack replacements and a price differential of
US\$50,000, we find a payback period of about 3 years. Based on sensitivity
analysis, we find that the fraction of the fleet that requires battery pack
replacements is a major factor. For the case with 100% replacement fraction,
the payback period could be as high as 5-6 years. We identify the price of
electricity as the second most important variable, where a price of
US$0.14/kWh, the payback period could go up to 5 years. Electric semi-trucks
are expected to lead to savings due to reduced repairs and magnitude of these
savings could play a crucial role in the payback period as well. With increased
penetration of autonomous vehicles, the annual mileage of semi-trucks could
substantially increase and this heavily sways in favor of electric semi-trucks,
bringing down the payback period to around 2 years at an annual mileage of
120,000 miles. There is an undeniable economic case for electric semi-trucks
and developing battery packs with longer cycle life and higher specific energy
would make this case even stronger.
