Any person who violates any provision of this chapter, or rule or order thereunder, shall be subject to a civil penalty, which shall be assessed by the Secretary, of not more than $25,000 for each violation. Each day of violation shall constitute a separate violation.

In the case of any electric powerplant granted an exemption, any person who operates such powerplant during any 12-calendar-month period in excess of that authorized in such exemption, shall be liable for a civil penalty, which shall be assessed by the Secretary. The amount of such civil penalty may not exceed $10 per barrel of petroleum or $3 per Mcf of natural gas used in operation of such powerplant in excess of that authorized in such exemption.