Per unit cost allocation of invested capital with anticipated non-level production: The case of extractive industries
The concept of equivalent annual annuity (EAA) has long been used as a method of costing recovery of invested capital and the required return on invested capital over the productive life of a capital project. Academic texts almost universally use EAA methodology with level payment streams (annuities) to allocate capital costs. We develop a methodology for allocating capital costs evenly over each unit of production for projects with anticipated non level production. This methodology uses a modified EAA approach that allows non-level annuity payment streams. Capital cost allocation is an important component in computing the value of extracted minerals for severance tax purposes; however, many firms and state and federal agencies use ad hoe depreciation schedules to allocate these costs. Ad hoc depreciation methods such as modified accelerated cost recovery system (MACRS) may be appropriate for income tax purposes but are inconsistent with commonly found requirements that severance taxes "shall be assessed on the wellhead or mine mouth fair market value." The modified EAA approach provides a straightforward alternative that is based on sound financial methodology.
Spahr, R., Schwebach, R., & Putnam, F. (1999). Per unit cost allocation of invested capital with anticipated non-level production: The case of extractive industries. Engineering Economist, 44 (4), 332-347. https://doi.org/10.1080/00137919908967527