Code of Maine Rules › 06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL › Chapter 167 - TRACKING AND REPORTING GROSS AND NET ANNUAL GREENHOUSE GAS EMISSIONS › Section 096-167-5 - Net GHG emissions estimates

Current through 2024-29, July 17, 2024
A.
Categories.
Estimates of net GHG emissions in Maine shall include
				estimates of emissions and sequestration from the following categories:
(1) Fossil fuels. Fossil fuel emissions shall
				be estimated in accordance with section 4. A.(2)(a)(ii)
				(CO2 from fossil fuel combustion) of this Chapter and
				reported by the following sectors: transportation, residential, industrial,
				electric power, and commercial.
(2)
				Waste. Emissions from waste shall be estimated in accordance with sections 4.
				A.(2)(a)(ix) (Municipal solid waste), 4. A.(2)(a)(xi) (Wastewater), and
				4.A.(3)(c) (Solid waste) of this Chapter.
(3) Forests (live biomass, dead biomass, and
				soils)
(a) Acreage data shall be obtained from
				the USGS National Land Cover Database (NLCD).
(b) Aboveground forest carbon data shall be
				obtained from the USDA Forest Service Forest Inventory and Analysis database
				(FIA). Fluxes shall be calculated as the difference in stock inventories
				between the first and last years of the analysis window. Carbon estimation
				methods shall follow those outlined in Annex 3 of the EPA's "Inventory of US
				Greenhouse Gas Emissions and Sinks: 1990-2017" as published by EPA in 2019. The
				methods in this Annex 3 are incorporated by reference herein.
NOTE: The incorporated material can be accessed at
www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2017
,
				  and copies of the incorporated material are also available from the Department
				  by calling (207) 287-2235.
(c) Soils data shall be obtained from the
				USDA Natural Resources Conservation Service SSURGO soils database. Soil fluxes
				shall be calculated as differences in soil carbon stock by land use change
				between the first and last years of the analysis window based on the
				NLCD.
(d) When the 'forest floor'
				data from the FIA partially includes the SSURGO total soil measurements, the
				FIA forest floor carbon estimates shall be subtracted from the total SSURGO
				soil carbon estimates in forest soil carbon stock difference
				calculations.
(e) Shrubland
				non-soil component estimates shall be included in the aboveground forestland
				estimates.
(4) Wood
				products (sawlogs, pulp, and landfilled). Sequestration of carbon in forest
				products shall be estimated based on timber flows (harvest minus export plus
				import) from the Maine Forest Service Annual Wood Processing Reports. Processed
				wood shall be divided into sawlogs, pulp logs, biomass, and fuelwood. The
				longevity of the products made from these four wood types shall be applied
				based on factors in the USFS For GATE Tool, which estimates wood product decay
				and deposition into landfills. Processed wood that could be utilized outside of
				Maine (i.e., exports) and wood processed elsewhere that could be utilized in
				Maine (i.e., imports) shall not be considered in this assessment.
(5) Wetlands (biomass and soils)
(a) Non-woody wetland soil carbon shall be
				estimated by:
(i) Using data from a direct
				monitoring network for non-woody wetland fluxes in Maine; or
(ii) Taking the non-woody wetland land use
				data from the NLCD database representing the first and last year of the
				analysis window years and assigning a carbon value from the SSURGO database.
				Changes in land area by non-woody wetland soil type over time shall be used to
				estimate fluxes.
(b)
				Woody wetlands, including forested swamps and shrub swamps, shall be accounted
				for in the forest estimates.
(6) Agriculture (emissions and soils)
(a) Emissions from agricultural activities
				shall be estimated in accordance with section 4.A.(2)(a)(i )(Agriculture) of
				this Chapter.
(b) Accounting for
				agricultural soil carbon from changes in farm practices may be included if the
				Department determines that an available data source and methodology are
				sufficiently representative of activities in Maine.
(7) Urban (biomass and soils)
(a) Urban aboveground biomass carbon shall be
				based on the forest stock change from the FIA database.
(b) Urban soil carbon estimates shall be
				based on NLCD land use data that includes developed lands with different
				intensities ranging from open space to low, medium, and high intensity with the
				associated soil carbon data for the urban land use change from the SSURGO
				database.
(8) Inland
				waters (sedimentation). Inland water carbon estimates shall be based on the
				amount of carbon delivered to the ocean at the mouth of a river. Specifically,
				this is the transport of dissolved organic carbon from watersheds through
				surface waters (e.g., lakes and streams) to rivers and exported to the ocean.
				(This estimate shall not include dissolved inorganic carbon.) A preliminary
				estimate of 20% shall be assumed to represent the amount of dissolved organic
				carbon delivered to the ocean that is then sequestered by sedimentation, with
				the rest assumed to be lost to photo-oxidation and decomposition back to the
				atmosphere.
(9) Coastal waters
				(sedimentation and biomass; blue carbon)
(a)
				Blue carbon stock and flux estimates for salt marshes shall be based on:
(i) Total salt marsh area as reported in the
				most recent Maine Tidal Marshes Map produced by the Department of Agriculture,
				Conservation and Forestry, Maine Natural Areas Program.
(ii) The average carbon density over the
				upper 1 meter.
(iii) The average
				burial rate flux for coastal marsh sediments.
(b) Blue carbon stock and flux estimates for
				eelgrass shall be based on:
(i) The eelgrass
				meadow area determined by the State of Maine agencies and partners eelgrass
				surveys (e.g., Maine Department of Environmental Protection, Maine Department
				of Marine Resources, and partner mapping efforts where quality assurance is
				known an accepted by Department staff).
(ii) The average carbon density over the
				upper 1 meter.
(iii) The average
				burial rate flux for eelgrass beds.
(c) Carbon stocks shall be calculated by
				multiplying the ecosystem area in square meters by the carbon density of a
				one-square-meter area. Carbon fluxes shall be calculated by multiplying the
				ecosystem area by the burial rate.