2022—Pub. L. 117–169, § 13302(c)(2), substituted “clean energy credit” for “energy efficient property” in section catchline.

Subsec. (a)(6). Pub. L. 117–169, § 13302(b)(1), amended par. (6) generally. Prior to amendment, par. (6) read as follows: “the qualified biomass fuel property expenditures, and”.

Subsec. (d)(3). Pub. L. 117–169, § 13302(c)(1), inserted “, without regard to subparagraph (D) thereof” after “section 48(c)(1)”.

Subsec. (d)(6). Pub. L. 117–169, § 13302(b)(2), amended par. (6) generally. Prior to amendment, text read as follows:

“(A) In general.—The term ‘qualified biomass fuel property expenditure’ means an expenditure for property—

“(i) which uses the burning of biomass fuel to heat a dwelling unit located in the United States and used as a residence by the taxpayer, or to heat water for use in such a dwelling unit, and

“(ii) which has a thermal efficiency rating of at least 75 percent (measured by the higher heating value of the fuel).

“(B) Biomass fuel.—For purposes of this section, the term ‘biomass fuel’ means any plant-derived fuel available on a renewable or recurring basis.”

Subsec. (g)(2). Pub. L. 117–169, § 13302(a)(2)(A), substituted “before January 1, 2022, 26 percent,” for “before January 1, 2023, 26 percent, and”.

Subsec. (g)(3) to (5). Pub. L. 117–169, § 13302(a)(2)(B), added pars. (3) to (5) and struck out former par. (3) which read as follows: “in the case of property placed in service after December 31, 2022, and before January 1, 2024, 22 percent.”

Subsec. (h). Pub. L. 117–169, § 13302(a)(1), substituted “December 31, 2034” for “December 31, 2023”.

2020—Subsec. (a)(6). Pub. L. 116–260, § 148(b)(1), added par. (6).

Subsec. (d)(6). Pub. L. 116–260, § 148(b)(2), added par. (6).

Subsec. (g)(2). Pub. L. 116–260, § 148(a)(2)(A), substituted “January 1, 2023” for “January 1, 2021”.

Subsec. (g)(3). Pub. L. 116–260, § 148(a)(2)(B), substituted “after December 31, 2022, and before January 1, 2024” for “after December 31, 2020, and before January 1, 2022”.

Subsec. (h). Pub. L. 116–260, § 148(a)(1), substituted “December 31, 2023” for “December 31, 2021”.

2018—Subsec. (a). Pub. L. 115–123, § 40402(b)(1), substituted “the sum of the applicable percentages of—”, pars. (1) to (5), and concluding provisions for “the sum of—

“(1) the applicable percentage of the qualified solar electric property expenditures made by the taxpayer during such year,

“(2) the applicable percentage of the qualified solar water heating property expenditures made by the taxpayer during such year,

“(3) 30 percent of the qualified fuel cell property expenditures made by the taxpayer during such year,

“(4) 30 percent of the qualified small wind energy property expenditures made by the taxpayer during such year, and

“(5) 30 percent of the qualified geothermal heat pump property expenditures made by the taxpayer during such year.”

Subsec. (g). Pub. L. 115–123, § 40402(b)(2), struck out “paragraphs (1) and (2) of” before “subsection (a),” in introductory provisions.

Subsec. (h). Pub. L. 115–123, § 40402(a), substituted “December 31, 2021.” for “December 31, 2016 (December 31, 2021, in the case of any qualified solar electric property expenditures and qualified solar water heating property expenditures).”

2015—Subsec. (a)(1), (2). Pub. L. 114–113, § 304(a)(1), substituted “the applicable percentage” for “30 percent”.

Subsec. (g). Pub. L. 114–113, § 304(a)(4), added subsec. (g). Former subsec. (g) redesignated (h).

Pub. L. 114–113, § 304(a)(2), inserted “(December 31, 2021, in the case of any qualified solar electric property expenditures and qualified solar water heating property expenditures)” before period at end.

Subsec. (h). Pub. L. 114–113, § 304(a)(3), redesignated subsec. (g) as (h).

2013—Subsec. (c). Pub. L. 112–240 amended subsec. (c) generally. Prior to amendment, subsec. (c) related to limitation based on amount of tax and carryforward of unused credit.

2009—Subsec. (b)(1). Pub. L. 111–5, § 1122(a)(1), amended par. (1) generally. Prior to amendment, par. (1) related to maximum credit with respect to qualified solar water heating property expenditures, qualified fuel cell property, qualified small wind energy property expenditures, and qualified geothermal heat pump property expenditures.

Subsec. (e)(4). Pub. L. 111–5, § 1122(a)(2)(A), added par. heading and introductory provisions and struck out former heading and introductory provisions. Former introductory provisions read as follows: “In the case of any dwelling unit which is jointly occupied and used during any calendar year as a residence by two or more individuals the following rules shall apply:”.

Subsec. (e)(4)(A). Pub. L. 111–5, § 1122(a)(2)(A), added subpar. (A) and struck out former subpar. (A) which related to maximum amount of expenditures allowed for credit in jointly occupied dwelling units with respect to qualified solar water heating property expenditures, qualified fuel cell property, qualified small wind energy property expenditures, and qualified geothermal heat pump property expenditures.

Subsec. (e)(4)(C). Pub. L. 111–5, § 1122(a)(2)(B), struck out subpar. (C) which read as follows: “Subparagraphs (A) and (B) shall be applied separately with respect to expenditures described in paragraphs (1), (2), and (3) of subsection (d).”

Subsec. (e)(9). Pub. L. 111–5, § 1103(b)(2)(B), struck out par. (9). Text read as follows: “For purposes of determining the amount of expenditures made by any individual with respect to any dwelling unit, there shall not be taken into account expenditures which are made from subsidized energy financing (as defined in section 48(a)(4)(C)).”

2008—Subsec. (a)(4). Pub. L. 110–343, § 106(c)(1), added par. (4).

Subsec. (a)(5). Pub. L. 110–343, § 106(d)(1), added par. (5).

Subsec. (b)(1). Pub. L. 110–343, § 106(b)(1), amended par. (1) as amended by Pub. L. 110–343, § 106(c)(2) and (d)(2), by redesignating subpars. (B) to (E) as (A) to (D), respectively, and striking out former subpar. (A) which read as follows: “$2,000 with respect to any qualified solar electric property expenditures,”.

Subsec. (b)(1)(D). Pub. L. 110–343, § 106(c)(2), added subpar. (D).

Subsec. (b)(1)(E). Pub. L. 110–343, § 106(d)(2), added subpar. (E).

Subsec. (c). Pub. L. 110–343, § 106(e)(1), amended heading and text of subsec. (c) generally. Prior to amendment, subsec. (c) related to carryforward of unused credit.

Subsec. (d)(4). Pub. L. 110–343, § 106(c)(3)(A), added par. (4).

Subsec. (d)(5). Pub. L. 110–343, § 106(d)(3), added par. (5).

Subsec. (e)(4)(A). Pub. L. 110–343, § 106(b)(2), amended subpar. (A) as amended by Pub. L. 110–343, § 106(c)(4) and (d)(4), by redesignating cls. (ii) to (v) as (i) to (iv), respectively, and striking out former cl. (i) which read as follows: “$6,667 in the case of any qualified solar electric property expenditures,”.

Subsec. (e)(4)(A)(iv). Pub. L. 110–343, § 106(c)(4), added cl. (iv).

Subsec. (e)(4)(A)(v). Pub. L. 110–343, § 106(d)(4), added cl. (v).

Subsec. (g). Pub. L. 110–343, § 106(a), substituted “December 31, 2016” for “December 31, 2008”.

2006—Subsecs. (a)(1), (b)(1)(A). Pub. L. 109–432, § 206(b)(1), substituted “solar electric property expenditures” for “photovoltaic property expenditures”.

Subsec. (d)(2). Pub. L. 109–432, § 206(b)(2), substituted “solar electric property expenditure” for “photovoltaic property expenditure” in heading and text.

Subsec. (e)(4)(A)(i). Pub. L. 109–432, § 206(b)(1), substituted “solar electric property expenditures” for “photovoltaic property expenditures”.

Subsec. (g). Pub. L. 109–432, § 206(a), substituted “2008” for “2007”.

2005—Subsec. (b)(1). Pub. L. 109–135, § 402(i)(1), inserted “(determined without regard to subsection (c))” after “subsection (a)” in introductory provisions.

Subsec. (c). Pub. L. 109–135, § 402(i)(3)(E), reenacted heading without change and amended text generally. Prior to amendment, text read as follows: “If the credit allowable under subsection (a) exceeds the limitation imposed by section 26(a) for such taxable year reduced by the sum of the credits allowable under this subpart (other than this section), such excess shall be carried to the succeeding taxable year and added to the credit allowable under subsection (a) for such succeeding taxable year.”

Subsec. (e)(4)(A), (B). Pub. L. 109–135, § 402(i)(2), amended subpars. (A) and (B) generally. Prior to amendment, subpars. (A) and (B) read as follows:

“(A) The amount of the credit allowable, under subsection (a) by reason of expenditures (as the case may be) made during such calendar year by any of such individuals with respect to such dwelling unit shall be determined by treating all of such individuals as 1 taxpayer whose taxable year is such calendar year.

“(B) There shall be allowable, with respect to such expenditures to each of such individuals, a credit under subsection (a) for the taxable year in which such calendar year ends in an amount which bears the same ratio to the amount determined under subparagraph (A) as the amount of such expenditures made by such individual during such calendar year bears to the aggregate of such expenditures made by all of such individuals during such calendar year.”

Pub. L. 117–169, title I, § 13302(d), Aug. 16, 2022, 136 Stat. 1947, provided that:

Pub. L. 116–260, div. EE, title I, § 148(c)(1), Dec. 27, 2020, 134 Stat. 3056, provided that: “The amendments made by subsection (a) [amending this section] shall apply to property placed in service after December 31, 2020.”

Amendment by section 148(b) of Pub. L. 116–260 applicable to expenditures paid or incurred in taxable years beginning after Dec. 31, 2020, see section 148(c)(2) of div. EE of Pub. L. 116–260, set out as a note under section 25C of this title.

Pub. L. 115–123, div. D, title I, § 40402(c), Feb. 9, 2018, 132 Stat. 148, provided that: “The amendment made by this section [amending this section] shall apply to property placed in service after December 31, 2016.”

Pub. L. 114–113, div. P, title III, § 304(b), Dec. 18, 2015, 129 Stat. 3040, provided that: “The amendments made by this section [amending this section] shall take effect on January 1, 2017.”

Amendment by Pub. L. 112–240 applicable to taxable years beginning after Dec. 31, 2011, see section 104(d) of Pub. L. 112–240, set out as a note under section 23 of this title.

Amendment by section 1103(b)(2)(B) of Pub. L. 111–5 applicable to taxable years beginning after Dec. 31, 2008, see section 1103(c)(2) of Pub. L. 111–5, set out as a note under section 25C of this title.

Pub. L. 111–5, div. B, title I, § 1122(b), Feb. 17, 2009, 123 Stat. 324, provided that: “The amendments made by this section [amending this section] shall apply to taxable years beginning after December 31, 2008.”

Amendment by Pub. L. 110–343 applicable to taxable years beginning after Dec. 31, 2007, except that amendment by section 106(b) of Pub. L. 110–343 applicable to taxable years beginning after Dec. 31, 2008, see section 106(f)(1), (2) of Pub. L. 110–343, set out as an Effective and Termination Dates of 2008 Amendment note under section 23 of this title.

Amendment by section 402(i)(3)(E) of Pub. L. 109–135 subject to title IX of the Economic Growth and Tax Relief Reconciliation Act of 2001, Pub. L. 107–16, § 901, in the same manner as the provisions of such Act to which such amendment relates, see section 402(i)(3)(H) of Pub. L. 109–135, set out as a note under section 23 of this title. Title IX of Pub. L. 107–16 was repealed by Pub. L. 112–240, title I, § 101(a)(1), Jan. 2, 2013, 126 Stat. 2315.

Amendments by Pub. L. 109–135 effective as if included in the provisions of the Energy Policy Act of 2005, Pub. L. 109–58, to which they relate, except that amendment by section 402(i)(3)(E) of Pub. L. 109–135 is applicable to taxable years beginning after Dec. 31, 2005, see section 402(m) of Pub. L. 109–135, set out as a note under section 23 of this title.

Section applicable to property placed in service after Dec. 31, 2005, in taxable years ending after such date, see section 1335(c) of Pub. L. 109–58, set out as an Effective and Termination Dates of 2005 Amendments note under section 23 of this title.