Page 237 - Sustainable On-Site CHP Systems Design, Construction, and Operations

210 De s i g n

cost threshold. If the threshold is exceeded, then the technology may be excluded from
consideration. Typically, cost-effectiveness analyses are conducted in a “top-down”
fashion, starting with the technology that is expected to result in the lowest emissions
and eliminating options until a cost-effective or universally achievable solution is iden-
tified. Again, not all permitting agencies will allow for the selection of control technolo-
gies based upon cost-effectiveness, and even those that do consider cost-effectiveness
may also apply basic achievable technology standards which include emissions control
equipment, regardless of cost.
If the permitting agency allows technology options to be excluded based upon a
cost-effectiveness demonstration, it will be advantageous for the project engineer or
developer to fully understand both the capital and operating costs of each technology
option. Most regulatory agencies offer guidance and models for conducting cost-
effectiveness analyses. Regulatory agencies may also provide generally accepted values
for items such as construction overhead costs, but the project engineer most likely has a
better idea of what the costs attributed to each technological option may truly be in his
locality. Table 12-2 includes a list of the types of costs that are typically considered in a
technology cost-effectiveness analysis.

Air Emissions Inventory
Once the project’s operating schedule, CHP system configuration, and control tech-
nology are selected, the applicant and permitting agency can then proceed to develop
an emissions inventory. The inventory serves as the foundation for completing any
additional impact analyses and compliance assessments, relative to air quality. Depending
upon permitting requirements, the emissions inventory may include any or all of the
pollutants identified in Table 12-1 and is intended to reflect the project operating loads
and schedule as proposed by the engineer or developer. Emission factors from vendors,
clearinghouses, and other data sources are also used to compile the inventory.
The project engineer or developer should be prepared to discuss inventory struc-
ture and protocol with the permitting agency prior to initiating work on the emissions
inventory. The structure of the inventory will be dependent upon the permitting agency
and the rules or policies that are driving its development. Normally, the inventory will
reflect potential peak and average hourly emissions. If the project engineer or developer
is expected to determine health risks and ambient air quality risks attributable to the
project, then average annual emissions will also likely need to be quantified for the
inventory. Monthly and quarterly emission profiles may also be needed based upon
applicable regulations and policies.

Analyzing Air Quality Impacts and Determining Compliance with Applicable
Regulations
The emissions inventory serves as the first step in determining the project’s environ-
mental impacts. The following steps, such as dispersion modeling, air quality impact
analyses, and health risk assessments, may not be required in all cases. Where these
additional analyses are required, the permitting authority may assume responsibility
for their completion. The project engineer or developer should confirm that these anal-
yses are required and confirm who is responsible for their completion. Ultimately, these
analyses will be combined with the previously discussed technology assessment to
serve as the foundation for an assessment of compliance with applicable laws, ordinances,
and regulations.