Page 339 - Sustainable On-Site CHP Systems Design, Construction, and Operations

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Billing
For those owner-operators who charge customers for CHP plant–generated utilities,
accurate and clear billing is important in sustaining efficient CHP operations as it pro-
vides the funding for operations, maintenance, and reserve funds necessary for future
equipment replacement. Billing best practices are those practices that are

• Transparent
• Auditable
• Fair (reasonable)
• Easy to follow
• Follow generally accepted accounting principles (GAAP)
• Account for all costs (including capital)

Following these best practices, all costs associated with producing power, steam,
and chilled water are appropriately accounted for and assigned, including

• Fuel
• Operating staff
• Maintenance
• Purchased power/standby charges
• Administration
• Water/chemicals
• Supplies
• Permitting/source testing
• Debt service
• Depreciation and/or reserve fund
Whenever possible, cost should be assigned to the applicable individual utility ser-
vice. Work on the electrical generator should be assigned to the cost of producing electric-
ity. If the cost is strictly for providing heat, assign the cost to the cost of generating heat. If
a cost cannot be allocated to either electricity or thermal production, the cost should be
shared between both utilities. Different methods exist to properly allocate costs to shared
utilities. One method is simply to assign half of the costs to electricity service and half of
the costs to thermal energy recovered. Other cost splits may have more merit including
dividing the costs proportionally to match the actual proportional value of the utilities.
Parasitic loads should also be computed in order to determine net output. Examples
of parasitic loads include
• Natural gas compressors
• CHP plant pumps
• Cooling tower fans
• Water treatment systems
• Deaerating (DA) tank (steam)