Section 503.20 - Purpose and scope(a) This subpart implements the provisions contained in section 211 of the Act with regard to temporary exemptions for new facilities.(b) This subpart establishes the criteria and standards which owners or operators of new powerplants who petition for a temporary exemption must meet to sustain their burden of proof under the Act.(c) All petitions for temporary exemptions shall be submitted in accordance with the procedures set out in part 501 of this chapter and the applicable requirements of part 503 of these regulations.(d) The duration of any temporary exemption granted under this subpart shall be measured from the date that the facility is placed in service using petroleum or natural gas.46 FR 59903, Dec. 7, 1981, as amended at 54 FR 52894, Dec. 22, 1989