(b) All public utilities subject to the provisions of this chapter shall pay a special license fee in addition to any and all fees now required by law. The amount of such fees shall be fixed by the public service commission and such fee shall not exceed forty cents on each one hundred dollars of total gross revenue and shall be levied by it upon each of such public utilities, in the proportion which the total gross revenue derived from intrastate business done by each of such public utilities in the calendar year next preceding bears to the total gross revenue derived from intrastate business done in such year by all public utilities subject to regulation by the public service commission, in addition to such fees as may be fixed by the public service commission under the provisions of subsection (a) hereof and which fees shall be paid on or before the first day of July in each year. Such sum shall be paid into the state treasury and be kept, appropriated and used as provided in subsection (a) hereof.
(c) Any balance remaining in said fund at the end of any fiscal year shall not revert to the treasury but shall remain in said fund and may be appropriated and used as provided in subsection (a) hereof in the ensuing fiscal years.