4.— Schedule 1 to the Act of 1999 is amended—

(a) by the substitution of the following for paragraphs 16 and 17:

“16. For the purposes of meeting expenses properly incurred by the Commission in the discharge of its functions under this Act, the Commission may make an order (in this Act referred to as a ‘levy order’) imposing a levy to be paid each year on such class or classes of—

(a) energy undertakings, or

(b) petroleum undertakings,

as may be specified by the Commission in the order and separate orders may be made under this paragraph in respect of electricity undertakings, natural gas undertakings and petroleum undertakings and in respect of different classes of such undertakings.

17. Whenever a levy order is made under paragraph 16 there shall be paid to the Commission by each undertaking to which the levy order applies such amount as shall be appropriate having regard to the terms of the levyorder.”,

(b) by the substitution of the following for paragraph 20:

“20. (1) Any excess of the revenue of the Commission over its expenditure in any year shall be applied by the Commission to meet its expenses in the following year and the levy for that year shall take into account such excess.

(2) Any expenses incurred by the Commission which are not recovered by the levy payable for a particular year may be recovered by the Commission on foot of a levy order in a subsequent year.

(3) In making a subsequent levy order the Commission shall, in so far as is reasonably practicable, apply the amount of the excess of revenue in a particular year or the amount of expenses not recovered in a particular yearto the class of undertaking to which it most closely relates.”,

(c) by the substitution of the following for paragraph 25(aa):

“(aa) shall ensure, as far as is reasonably practicable, that such accounts identify separately in regard to the gas, electricity and petroleum sectors all elements of cost and revenue, with the basis of their calculation and the detailed attribution methods used, related to the discharge of the Commission’s functions under this Act,”.