Except for adjustments of the performance standard on a case-by-case basis under KRS 224.20-144, the performance standard that shall be established for existing coal-fired electric generating units shall be based on the following:
(1) The best system of emission reduction which has been adequately demonstrated for coal-fired electric generating units subject to the performance standard. Best system of emission reduction shall take into account the cost of:
(a) Achieving the emission reduction;
(b) Impacting non-air-quality health and the environment; and (c) Maintaining energy requirements needed to serve the load on the electric generating unit;
(2) Reductions in emissions of carbon dioxide that can reasonably be achieved through measures undertaken at each coal-fired electric generating unit; and (3) Efficiency and other measures that can be undertaken at each coal-fired electric generating unit to reduce its carbon dioxide emissions without doing the following:
(a) Switching from coal to other fuels;
(b) Co-firing other fuels with coal; or (c) Limiting the utilization of the electric generating unit.