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Appendix E. Greenhouse Gas Emissions and Costs In Chapter 3 of the report, MRW provided an estimate of Alameda CCA's annual Greenhouse Gas (GHG) emissions and compared these with the emissions for the same load under the PG&E supply portfolio. The methodology used to calculate both figures is included in this appendix, along with an estimate of Alameda CCA's cost of emissions from purchased power("indirect emissions"). Methodology for calculating Alameda CCA's indirect GHG emissions GHG emissions for Alameda CCA will be indirect since the CCA does not plan to generate its own power(i.e., the emissions are embedded in fossil-fuel power that the CCA purchases). These emissions are estimated based on(1) a forecast of the emissions rate for Alameda CCA's fossil generation supply and(2) a forecast of the amount of Alameda CCA's fossil generation supply, developed by subtracting expected renewable and hydroelectric generation from the projected wholesale power requirement to serve the CCA's load.4o MRW calculated the emissions rate for Alameda CCA's fossil generation supply by estimating the amount of natural gas that will need to be burned to generate the CCA's fossil generation and the GHG emissions rate for natural gas combustion.41 The amount of natural gas needed was estimated based on the average heat rate for the marginal generation plants on the CAISO system. MRW used public data from CAISO's OASIS platform and Platt's Gas Daily reports to calculate this average heat rate for 2015.42 MRW extended the forecast to 2030 using the expected changes to the average heat rate in California from the EIA's 2015 Annual Energy Outlook.43 MRW estimated the total annual GHG emissions for the Alameda CCA program as a product of the total energy purchased at wholesale electric market(kWh) and the rate of GHG emissions (tonnes CO2-equivalent/kWh). 4°MRW assumed no GHG emissions for the renewable and hydroelectric supply. 41 The GHG emissions rate for natural gas combustion is obtained from U.S.EIA.Electric Power Annual(EPA), February 16,2016,Table A.3.https://www.eia.gov/electricity/annual/html/epa_a_03.html 42 MRW calculated the average heat rate of the marginal generation plants in 2015 by dividing the monthly average wholesale electric market price,net of operations and maintenance costs and GHG emissions costs,by the monthly average natural gas price.For the electricity prices,we used the average of the 2015 hourly locational marginal price for node TH_NP15_GEN-APND;for the natural gas prices, we used the average of burnertip natural gas price for PG&E. 43 U.S.Energy Information Administration."2015 Annual Energy Outlook,"Table 55.20,Western Electricity Coordinating Council.(Note that EIA does not provide a forecast of the marginal heat rate.) E- 1