1500 KVA per truck for 100 trucks is like adding
100 cranes in a terminal. In this example, one can
easily see the impact and the importance of the KVA
assigned for each truck.
Under the present circumstances where projects
are evaluated and authorized to proceed to design,
such procedures do not allocate the time required
to consider the determination of KVA ratings. To
proceed with the electrical design, the designer
must have this KVA rating. With no other option
available to an electrical designer, and no guidance
from management, the electrical designer alone
determines a KVA rating. Taking what the designer
feels may be the safest approach, this rating is
usually ranked on the higher end. This approach
results in an installation and maintenance that is
much more expensive for the end-user with no real
benefit.
In the present environment, the best authority to
determine the KVA rating for trucks would be the
highest-ranking executive in an organization, who
has a direct interest in making sure costs remain
checked. Port commissioners, port executives, and
terminal operators are in a position to influence
reaching the proper KVA determination.
Properly applied KVA rating for a truck, top loader,
or an RTG would reduce installation cost by 50%
to 75% compared to an installation without such
considerations. In some cases, the maintenance cost
will be eliminated altogether due to the elimination
of unnecessary equipment and installation.
Comparison of Trucks with “Cold Ironing”
Based on experience with gantry cranes, ships
and reefers, it’s worthwhile to determine the KVA
requirements for the trucks, top loaders, and
the RTGs. This is not intended to give a detailed
explanation of all technical parameters necessary
to determine how the KVA rating of these machines
are calculated, but rather to highlight the crucial
considerations of these machines and their impact
on the KVA rating.
From the port terminal operator’s perspective, since
time saved has enormous value in serving their ships
at berth, any operation must be performed quickly.
If a truck is operating electrically, this means the
vehicle must have stored energy. Stored electrical
energy in the batteries placed on the truck is used
to move throughout the terminal to haul goods. After
hours of operation, the truck will deplete the stored
electrical energy from the batteries, which are
required to be recharged.
The battery capacity will limit the number of hours
available for trucking service. Port of Long Beach
(POLB) and Port of Los Angeles (POLA) conducted a
study where it was agreed to standardize the truck
capacities at 207 KVA each. Some manufacturers
are already providing 300 KW (or KVA) batteries.
However, over time the KVA required by each truck
will increase, as it did with reefers and gantry
cranes.
The number of trucks in a typical port terminal is
anywhere from 35 to as many as 170. Let’s assume
there are 100 trucks in our analysis terminal. Given
that each container ship requires anywhere from
1500 KVA to 3500 KVA, we will use 2500 KVA and
compare this figure with the requirements of a truck.
Each truck will require 300 KVA, which means for 100
trucks in a terminal, the electrical power required
for the truck batteries will be 30,000 KVA. In other
words, truck electrification will require 12 times
more electrical power than one ship in a typical port
terminal.
Truck Charging Impact
The terminal operator will supply the electrical
power necessary to charge the batteries on the
truck. The terminal operator will have to install the
electrical infrastructure required to facilitate truck
battery recharging. The two parameters for truck
electrifications are the KVA rating of the truck,
and the time required to charge the batteries.
We set truck KVA at 300 and charging time for 15
minutes. Increasing the 300 KVA will increase the
electrical power necessary for the terminal operator
to deliver. Decreasing the time required to charge
the batteries, would make it necessary to increase
the 300 KVA to a bigger number, meaning bigger
electrical service from the utility company and
bigger electrical substations.
Top Loader and RTG Charging Impact
Similar to the truck charging, top loaders and RTGs
will have a more significant impact on terminal
electrification. These machines require more
power in KVA and will also require more stringent
requirements for charging. If electrification of a
300 KVA truck has a significant impact on terminal
electrification, then a 1000 KVA top-loader or RTG
will have an even greater impact.
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