5(1)For the purposes of this Schedule an Electricity Board shall be treated, as respects any year, as carrying on generating activities, or carrying on such activities in a particular area, if (but only (f) on the thirty-first day of March falling next but one before the beginning of that year there was a generating station in commission for operation by the Board, or as the case may be, there was a generating station in commission as aforesaid in that area.
(2)For the purposes of this Schedule the generating capacity or aggregate generating capacity of an Electricity Board for any year shall be taken to be the installed capacity or aggregate installed capacity, that is to say the maximum amount of electricity, as certified by the Board, capable of being generated in the station or stations in question at the thirty-first day of March falling next but one before the beginning of that year; and the said maximum amount shall be certified on the footing that all generators which were installed at any thirty-first day of March were capable of being fully used at that time.
(3)For the purposes of this Schedule a generating station situated partly in one rating area and partly in one or more other rating areas shall be treated as situated in each of the areas and its generating capacity, on any date, shall be treated as apportioned between the areas in such manner as may be agreed between the rating authorities of the areas and the Electricity Board.
(4)If the apportionment required by the foregoing sub-paragraph has not been agreed before the end of the month of September following the date as at which it is to be made, it shall be made by the Minister and notified by him to the rating authorities and the Board as soon as may be after the end of that month.
(5)For the purposes of this Schedule any group of premises lying within one curtilage and occupied for the purposes of the generation of electricity shall be treated as one generating station; and a group of premises shall not be treated as not lying within one curtilage by reason only that it is traversed by a public highway or inland waterway.