La Mesa Greenhouse Gas Inventory 2014

Transcription

1 La Mesa Greenhouse Gas Inventory 2014 Introduction This report summarizes community scale greenhouse gas (GHG) emissions in La Mesa for 2010, 2011, and Community scale emissions include six sectors: electricity, natural gas, transportation, water, solid waste, and wastewater. Emissions from water are those associated with water treatment and distribution only. Emissions from the electricity, natural gas, transportation, solid waste, and water sectors were calculated using the ICLEI Community Protocol to the extent possible. Wastewater emissions were estimated using proxy data from the Point Loma Wastewater Treatment Plant and wastewater generation data for La Mesa. Results Table 1 summarizes the results of the La Mesa GHG Inventory for 2010, 2011, and Sector Electricity 90,610 90, ,658 Transportation 76,192 75,868 75,285 Natural Gas 49,418 50,431 46,778 Solid Waste 21,799 18,222 15,447 Water 7,613 7,676 7,739 Wastewater 2,441 2,519 2,249 Total (MT CO2e) 248, , ,156 Table 2 summarizes per capita emissions in La Mesa for the inventory years. Per capita emissions should only be compared within one inventory series, due to differences in methodology and forecasts. Per Capita Emissions (MT CO2e) In 2012, La Mesa emitted an estimated 254,156 metric tons (MT) CO2e. These emissions are distributed by sector as shown by figure 1. Electricity demand contributes the most to overall greenhouse gas (GHG) emissions (42%), while wastewater contributes the least (1%).

2 Figure 1: Relative Breakdown of GHG Emissions in La Mesa (2012) Electricity EPIC estimated emissions from electricity using the Built Environment (BE.2) method from the ICLEI Community Protocol. Annual electricity demand for La Mesa was multiplied by the average annual electricity GHG emission factor for San Diego County, expressed in pounds of CO 2 e per megawatt hour (lbs CO2e/MWh). In 2012, emissions from the electricity sector were 106,658 MT CO2e. These emissions can be broken down further into residential and commercial/industrial categories, based on data provided by SDG&E. In 2012, 48,989 MT CO2e were emitted from commercial electricity use, while 41,621 MT CO2e can be attributed to residential electricity use. Figure 2 illustrates the percentage breakdown for 2012.

3 Figure 2: GHG Breakdown of Electricity Sector (2012) Natural Gas Emissions from natural gas consumption by La Mesa were estimated using method Built Environment (BE.1) from the ICLEI U.S. Community Protocol. To estimate emissions from the combustion of natural gas, EPIC multiplied community fuel use by an emissions factor for natural gas, based on data from the California Air Resources Board. The natural gas sector, which accounted for 18% of total GHG emissions in 2012, can also be broken down into the residential and commercial/industrial categories. For 2012, 12,353 MT CO2e can be attributed to commercial natural gas use, while 34,425 MT CO2e was emitted from residential natural gas use. The percentage breakdown is given in figure 3.

4 Figure 3: GHG Breakdown of Natural Gas Sector (2012) Transportation To estimate GHG emissions associated with on road transportation, we use vehicle miles traveled (VMT) and the emission rates associated with the vehicle classes. SANDAG provided regional VMT data for La Mesa for all vehicle types based on the Origin Destination (O D) method for 2010, 2020, and EPIC interpolated for the years not provided. The O D VMT method as proposed by the ICLEI Community Protocol estimates miles traveled based on where a trip originates and where it ends. For 2012, emissions from the transportation contributed to 30% of total GHG emissions in La Mesa, with 75,868 MT CO2e. Figure 4 gives breakdown of emissions by EMFAC vehicle class for the transportation sector for the year Light duty trucks contribute most to emissions (38,675 MT CO2e), while motorcycles contribute the least (160 MT CO2e).

5 Figure 4: GHG Emissions by Vehicle Class (2012) Solid Waste Solid waste emissions were estimated using method SW.4 from the ICLEI Community Protocol. This method uses disposed waste in a given year, the characterization of waste, and emissions factors from the U.S. EPA Waste Reduction Model (WARM) to estimate emissions from the disposal of solid waste. EPIC obtained data on solid waste disposal in La Mesa California Department of Resources Recycling and Recovery (CalRecycle) Disposal Reporting System (DRS). In 2010, emissions from solid waste were 21,799 MT CO2e. Emissions decreased by 2012, reaching 15,447 MT CO2e, proportional to the decrease in solid waste disposal by La Mesa. Water To the extent possible, emissions from energy use associated with treatment of water consumed by the La Mesa Community were estimated using the WW.14 method from the ICLEI Community Protocol. The method considers each element of the water cycle (upstream, supply and conveyance, treatment, and distribution) individually, using a community specific energy consumed per unit of water for each process of the water system. A sum of the emissions from each process is then taken to estimate total GHG emissions from a community s water use. In 2012, emissions from the water sector were 7,739 MT CO2e. About 90% of those emissions were a result of upstream energy use at 6,959 MT CO2e. The relative breakdown of emissions for the water sector are given in figure 5.

6 Figure 5: GHG Breakdown of Water Sector (2012) 8BWastewater Due to lack of consistent data for wastewater treatment facilities in the San Diego Region, emissions from the treatment of wastewater were estimated using data from Point Loma Wastewater Treatment Plant in the City of San Diego and used as a proxy for other plants in the region, in addition to wastewater disposal data from the. In 2012, emissions from the treatment of wastewater for La Mesa were 2,249 MT CO2e.