Civil Engineering Reference
In-Depth Information
understand the most important factors affecting the business case of the
project. Through a question-and-answer format, this section presents common
CNGrelated questions answered by NREL using the VICE model.
The business case targets municipal governments, which operate fleets
suited well for CNG vehicles because they drive circular routes that enable
refueling at the same station. These fleets are transit buses, school buses, and
refuse trucks. Municipal governments are also targeted because their primary
goal is to improve their residents' quality of life. This goal allows the
government to utilize all the advantages of CNG, including long-term cost-
effectiveness, more-consistent operational costs, increased energy security,
reduced greenhouse gas emissions, reduced local air pollution, and reduced
noise pollution. A forthcoming report will focus on private fleets that are
suited well for CNG, such as taxi cabs and delivery trucks.
VICE
M
ODEL
B
ASELINE
P
ARAMETERS
This analysis uses multiple input variables to simulate the financial
circumstances faced by municipal fleets. In this section, average or common
values are used to establish a baseline scenario for common operating
circumstances. This scenario provides a snapshot from which we can test the
sensitivity of CNG project economics to changes in various parameters.
CNG Station Cost
Station cost is derived by a cost calculator constructed by Rob Adams
with Marathon Technical Services (Marathon). The calculator replicates a
buffered fast-fill station, which is best suited for quickly fueling large numbers
of heavy-duty, high-fuel-capacity vehicles. It is recognized that under
scenarios with low throughput and large refueling windows, a time-fill station
might be preferred. However, under these scenarios, the calculator takes into
account the reduction in equipment needed by reducing the overall cost of the
station close to that of a comparable time-fill station. Therefore, the cost
estimate is realistic over a wide range of station sizes.
Constants in the calculator are as follows:
•
Spare ratio is 10%. This means that 10% of the fleet is expected to not
refuel on any given day.
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