393.1009.  Definitions. — As used in sections 393.1009 to 393.1015, the following terms mean:

  (1)  "Appropriate pretax revenues", the revenues necessary to produce net operating income equal to:

  (a)  The gas corporation's weighted cost of capital multiplied by the net original cost of eligible infrastructure system replacements, including recognition of accumulated deferred income taxes and accumulated depreciation associated with eligible infrastructure system replacements which are included in a currently effective ISRS; and

  (b)  Recover state, federal, and local income or excise taxes applicable to such income; and

  (c)  Recover all other ISRS costs;

  (2)  "Commission", the Missouri public service commission;

  (3)  "Eligible infrastructure system replacements", gas utility plant projects that:

  (a)  Do not increase revenues by directly connecting the infrastructure replacement to new customers;

  (b)  Are in service and used and useful;

  (c)  Were not included in the gas corporation's rate base in its most recent general rate case; and

  (d)  Replace or extend the useful life of an existing infrastructure;

  (4)  "Gas corporation", every corporation, company, association, joint stock company or association, partnership and person, their lessees, trustees or receivers appointed by any court whatsoever, owning, operating, controlling, or managing any gas plant operating for public use under privilege, license, or franchise now or hereafter granted by the state or any political subdivision, county, or municipality thereof as defined in section 386.020;

  (5)  "Gas utility plant projects" shall consist only of the following:

  (a)  Mains, valves, service lines, regulator stations, vaults, and other pipeline system components installed to comply with state or federal safety requirements as replacements for existing facilities that have worn out or are in deteriorated condition or that can no longer be installed under currently applicable safety requirements or any cast iron or steel facilities including any connected or associated facilities that, regardless of their material, age, or condition, are replaced as part of a qualifying replacement project in a manner that adds no incremental cost to a project compared to tying into or reusing existing facilities;

  (b)  Main relining projects, service line insertion projects, joint encapsulation projects, and other similar projects extending the useful life or enhancing the integrity of pipeline system components undertaken to comply with state or federal safety requirements; and

  (c)  Facilities relocations required due to construction or improvement of a highway, road, street, public way, or other public work by or on behalf of the United States, this state, a political subdivision of this state, or another entity having the power of eminent domain provided that the costs related to such projects have not been reimbursed to the gas corporation;

  (6)  "ISRS", infrastructure system replacement surcharge;

  (7)  "ISRS costs", depreciation expense and property taxes that will be due within twelve months of the ISRS filing associated with eligible system replacements less annual depreciation expenses and property taxes associated with any related facility retirements;

  (8)  "ISRS revenues", revenues produced through an ISRS exclusive of revenues from all other rates and charges.