Section 1. As used in this chapter the following words shall have the following meanings unless the context clearly requires otherwise:--
''Allowance'', an authorization to emit, during a specified year, up to 1 ton of carbon dioxide equivalent.
''Alternative compliance mechanism'', an action undertaken by a greenhouse gas emission source that achieves the equivalent reduction of greenhouse gas emissions over the same time period as a direct emissions reduction, that is approved by the department, and that is real, permanent, quantifiable, verifiable and enforceable.
''Carbon dioxide equivalent'', the amount of carbon dioxide by weight that would produce the same global warming impact as a given weight of another greenhouse gas, based on the best available science, including from the Intergovernmental Panel on Climate Change.
''Department'', the department of environmental protection.
''Direct emissions'', emissions from sources that are owned or operated, in whole or in part, by an entity or facility including, but not limited to, emissions from factory stacks, manufacturing processes and vents, and company owned or company-leased motor vehicles.
''Direct emissions reduction'', a greenhouse gas emission reduction action made by a greenhouse gas emissions source at that source.
''Emission'', emission of a greenhouse gas into the air.
''Emissions reduction measures'', programs, measures, standards, and alternative compliance mechanisms authorized pursuant to this chapter, applicable to sources or categories of sources that are designed to reduce emissions of greenhouse gases.
''Entity'', a person that owns or operates, in whole or in part, a source of greenhouse gas emissions from a generator of electricity or a commercial or industrial site including, but not limited to, a transportation fleet.
''Executive office'', the executive office of energy and environmental affairs.
''Facility'', a building, structure or installation located on contiguous or adjacent properties of an entity.
''Greenhouse gas'', any chemical or physical substance that is emitted into the air and that the department may reasonably anticipate will cause or contribute to climate change including, but not limited to, carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride.
''Greenhouse gas emissions limit'', an authorization, during a specified year, to emit up to a level of greenhouse gases specified by the secretary, expressed in tons of carbon dioxide equivalents.
''Greenhouse gas emissions source'', a source, or category of sources, of greenhouse gas emissions with emissions that are at a level of significance, as determined by the secretary, that its participation in the program established under this chapter will enable the secretary to effectively reduce greenhouse gas emissions and monitor compliance with the statewide greenhouse gas emissions limit.
''Indirect emissions'', emissions associated with the consumption of purchased electricity, steam and heating or cooling by an entity or facility.
''Leakage'', the offset of a reduction in emissions of greenhouse gases within the commonwealth by an increase in emissions of greenhouse gases outside the commonwealth.
''Market-based compliance mechanism'', (i) a system of market-based declining annual aggregate emissions limitations for sources or categories of sources that emit greenhouse gases; or (ii) greenhouse gas emissions exchanges, banking, credits and other transactions governed by rules and protocols established by the secretary or the regional greenhouse gas initiative, that result in the same greenhouse gas emissions reduction, over the same time period, as direct compliance with a greenhouse gas emissions limit or emission reduction measure adopted by the executive office pursuant to this chapter.
''Person'', an agency or political subdivision of the commonwealth, a state, public or private corporation or authority or an individual, trust firm, joint stock company, partnership, association or other entity or group thereof or an officer, employee or agent thereof.
''Secretary'', the secretary of energy and environmental affairs.
''Statewide greenhouse gas emissions'', the total annual emissions of greenhouse gases in the commonwealth, including all emissions of greenhouse gases from the generation of electricity delivered to and consumed in the commonwealth, accounting for transmission and distribution line losses, whether the electricity is generated in the commonwealth or imported; provided, however, that statewide greenhouse gas emissions shall be expressed in tons of carbon dioxide equivalents.
''Statewide greenhouse gas emissions limit'', the maximum allowable level of statewide greenhouse gas emissions in a given year, as determined by the secretary.