42 U.S. Code § 7651i - Election for additional sources
The owner or operator of any unit that is not, nor will become, an affected unit under section 7651b (e), 7651c, or 7651d of this title, or that is a process source under subsection (d) of this section, that emits sulfur dioxide, may elect to designate that unit or source to become an affected unit and to receive allowances under this subchapter. An election shall be submitted to the Administrator for approval, along with a permit application and proposed compliance plan in accordance with section 7651g of this title. The Administrator shall approve a designation that meets the requirements of this section, and such designated unit, or source, shall be allocated allowances, and be an affected unit for purposes of this subchapter.
(b) Establishment of baseline
The baseline for a unit designated under this section shall be established by the Administrator by regulation, based on fuel consumption and operating data for the unit for calendar years 1985, 1986, and 1987, or if such data is not available, the Administrator may prescribe a baseline based on alternative representative data.
(c) Emission limitations
Annual emissions limitations for sulfur dioxide shall be equal to the product of the baseline multiplied by the lesser of the unit’s 1985 actual or allowable emission rate in lbs/mmBtu, or, if the unit did not operate in 1985, by the lesser of the unit’s actual or allowable emission rate for a calendar year after 1985 (as determined by the Administrator), divided by 2,000.
(d) Process sources
Not later than 18 months after November 15, 1990, the Administrator shall establish a program under which the owner or operator of a process source that emits sulfur dioxide may elect to designate that source as an affected unit for the purpose of receiving allowances under this subchapter. The Administrator shall, by regulation, define the sources that may be designated; specify the emissions limitation; specify the operating, emission baseline, and other data requirements; prescribe CEMS or other monitoring requirements; and promulgate permit, reporting, and any other requirements necessary to implement such a program.
(e) Allowances and permits
The Administrator shall issue allowances to an affected unit under this section in an amount equal to the emissions limitation calculated under subsection (c) or (d) of this section, in accordance with section 7651b of this title. Such allowance may be used in accordance with, and shall be subject to, the provisions of section 7651b of this title. Affected sources under this section shall be subject to the requirements of sections 7651b, 7651g, 7651j, 7651k, 7651l, and 7651m of this title.
Any unit designated under this section shall not transfer or bank allowances produced as a result of reduced utilization or shutdown, except that, such allowances may be transferred or carried forward for use in subsequent years to the extent that the reduced utilization or shutdown results from the replacement of thermal energy from the unit designated under this section, with thermal energy generated by any other unit or units subject to the requirements of this subchapter, and the designated unit’s allowances are transferred or carried forward for use at such other replacement unit or units. In no case may the Administrator allocate to a source designated under this section allowances in an amount greater than the emissions resulting from operation of the source in full compliance with the requirements of this chapter. No such allowances shall authorize operation of a unit in violation of any other requirements of this chapter.
The Administrator shall issue regulations to implement this section not later than eighteen months after November 15, 1990.
(h) Small diesel refineries
The Administrator shall issue allowances to owners or operators of small diesel refineries who produce diesel fuel after October 1, 1993, meeting the requirements of subsection  7545(i) of this title.
(1) Allowance period
Allowances may be allocated under this subsection only for the period from October 1, 1993, through December 31, 1999.
(2) Allowance determination
The number of allowances allocated pursuant to this paragraph shall equal the annual number of pounds of sulfur dioxide reduction attributable to desulfurization by a small refinery divided by 2,000. For the purposes of this calculation, the concentration of sulfur removed from diesel fuel shall be the difference between 0.274 percent (by weight) and 0.050 percent (by weight).
(3) Refinery eligibility
As used in this subsection, the term “small refinery” shall mean a refinery or portion of a refinery—
(A) which, as of November 15, 1990, has bona fide crude oil throughput of less than 18,250,000 barrels per year, as reported to the Department of Energy, and
(4) Limitation per refinery
The maximum number of allowances that can be annually allocated to a small refinery pursuant to this subsection is one thousand and five hundred.
(5) Limitation on total
In any given year, the total number of allowances allocated pursuant to this subsection shall not exceed thirty-five thousand.
(6) Required certification
The Administrator shall not allocate any allowances pursuant to this subsection unless the owner or operator of a small diesel refinery shall have certified, at a time and in a manner prescribed by the Administrator, that all motor diesel fuel produced by the refinery for which allowances are claimed, including motor diesel fuel for off-highway use, shall have met the requirements of subsection  7545(i) of this title.
 So in original. Probably should be “section”.