(a) In this subtitle the following words have the meanings indicated.

(b) “Alternative compliance mechanism” means an action authorized by regulations adopted by the Department that achieves the equivalent reduction of greenhouse gas emissions over the same period as a direct emissions reduction.

(c) “Carbon dioxide equivalent” means the measurement of a given weight of a greenhouse gas that has the same global warming potential, measured over a specified period of time, as one metric ton of carbon dioxide.

(d) “Direct emissions reduction” means a reduction of greenhouse gas emissions from a greenhouse gas emissions source.

(e) “Greenhouse gas” includes carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.

(f) “Greenhouse gas emissions source” means a source or category of sources of greenhouse gas emissions that have emissions of greenhouse gases that are subject to reporting requirements or other provisions of this subtitle, as determined by the Department.

(g) “Leakage” means a reduction in greenhouse gas emissions within the State that is offset by a corresponding increase in greenhouse gas emissions from a greenhouse gas emissions source located outside the State that is not subject to a similar state, interstate, or regional greenhouse gas emissions cap or limitation.

(i) “Statewide greenhouse gas emissions” means the total annual emissions of greenhouse gases in the State, measured in metric tons of carbon dioxide equivalents, including all emissions of greenhouse gases from the generation of electricity delivered to and consumed in the State, and line losses from the transmission and distribution of electricity, whether the electricity is generated in-State or imported.