Nevada Greenhouse Gas Inventory and Reference Case Projections

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Electricity Trade and Allocation of GHG Emissions FINAL Nevada GHG Inventory and Reference Case Projection CCS, July 2007 Nevada is part of the interconnected Western Electricity Coordinating Council (WECC) region - a vast and diverse area covering 1.8 million square miles and extending from Canada through Mexico, including all or portions of 14 western states. The inter-connected region allows electricity generators and consumers to buy and sell electricity across regions, taking advantage of the range of resources and markets. Electricity generated by any single plant enters the interconnected grid and may contribute to meeting demand throughout much of the region, depending on sufficient transmission capacity. Thus, it is challenging to define which emissions should be allocated to Nevada, and secondly in estimating these emissions both historically and into the future. Some utilities track and report electricity sales to meet consumer demand by fuel source and plant type; however, tracing sales to individual power plants may not be possible. In 2004, Nevada had 20 entities involved in providing electricity to state customers. The State’s two investor-owned utilities serve approximately 95 percent of the customers, and sell 88 percent of the electricity used. The State’s eight electric cooperatives serve 3 percent of the customers and account for 4.6 percent of sales. One federal and 8 public utilities account for the remaining 2.4 percent of customers and 7 percent of sales. The top 5 providers of retail electricity in the State are reported in Table A5. Table A5. Retail Electricity Providers in Nevada (2004) Entity Ownership Type 2004 GWh 1. Nevada Power Co Investor-Owned 19,014 2. Sierra Pacific Power Co Investor-Owned 8,627 3. Colorado River Comm of Nevada Public 1,564 4. Wells Rural Electric Co Cooperative 655 5. Valley Electric Assn, Inc Cooperative 391 Total Sales, Top Five Providers 30,251 Total, All Nevada 31,312 Source: EIA state electricity profiles In 2004, electricity demand (sales + losses 18 ) in Nevada was about 34,894 GWh, while electricity generation in the State was 37,652 GWh. Net exported electricity to other states accounts for the additional 2,758 GWh, but net exports generally encompass a mix of both imports and exports from the State. As mentioned above, 86 percent of the capacity at the Mohave power plant was under contract with out-of-state utilities. Other power plants have contracts with out-of-state utilities and Nevada utilities may own or have contracts with power plants outside of the State. Thus, electricity trade counts for a significant portion of the electric power associated with Nevada. 18 Nevada’s electricity losses are assumed to be 10 percent based on information from EPA’s Emission & Generation Resource Integrated database (EGRID), http://www.epa.gov/cleanenergy/egrid/index.htm. 10 percent is the average rate of losses, according to this dataset, over the period 1994-2000. Nevada Division of 22 Center for Climate Strategies Environmental Protection www.climatestrategies.us
FINAL Nevada GHG Inventory and Reference Case Projection CCS, July 2007 Since almost all states are part of regional trading grids, many states that have developed GHG inventories have grappled with the problem of how to account for electric sector emissions when electricity flows across state borders. Several approaches have been developed to allocate GHG emissions from the electricity sector to individual states for inventories. In many ways the simplest approach is production-based – emissions from power plants within the state are included in the state’s inventory. The data for this estimate are publicly available and unambiguous. However, this approach is problematic for states that import or export significant amounts of electricity. Under a production-based approach, characteristics of Nevada electricity consumption would not be fully captured since only emissions from in-state generation would be considered. An alternative is to estimate consumption-based or load-based GHG emissions, corresponding to the emissions associated with electricity consumed in the state. The load-based approach is currently being considered by states that import significant amounts of electricity, such as California, Oregon, and Washington. 19 By accounting for emissions from imported electricity, states can account for increases or decreases in fossil fuel consumed in power plants outside of the State, due to demand growth, efficiency programs, and other actions in the state. The difficulty with this approach is properly accounting for the emissions from imports and exports. Since the electricity flowing into or out of Nevada is a mix of all plants generating on the interconnected grid, it is impossible to physically track the sources of the electrons. The approach taken in this initial inventory is a simplification of the consumption-based approach. This approach, which one could term “Net-Consumption-based,” estimates consumption-based emissions as in-state (production-based) emissions times the ratio of total instate electricity consumption to in-state generation (net of losses) plus the emissions from the net imports. These figures were then adjusted to exclude contracted exports from the Mohave plant, which accounts for 40 percent of production-based emissions but provides only 14% of its power to in-state electricity consumers. 20 Emissions for net imports are calculated as net imports in GWh multiplied by an emission factor in GHG emissions per electricity generated (MTCO 2 e/GWh) for the imports. Estimating the mix of electricity generation for the imports/export of a state is possible and several states are developing data collection approaches to do this. Washington State has developed regular fuel disclosure reporting. 21 As a proxy for estimating the mix of historic and future GHG for Nevada’s electricity imports, emission factors that reflect the regional fuel mix were used. The region used for future emission factors is the Rocky Mountain portion of the WECC (excluding Nevada’s emissions) from the AEO2006. These regional emission factors were 0.66 19 See for example, the reports of the Puget Sound Climate Protection Advisory Committee (http://www.pscleanair.org/specprog/globclim/), the Oregon Governor’s Advisory Group On Global Warming (http://egov.oregon.gov/ENERGY/GBLWRM/Strategy.shtml), and the California Climate Change Advisory Committee, Policy Options for Reducing Greenhouse Gas Emissions From Power Imports - Draft Consultant Report (http://www.energy.ca.gov/2005publications/CEC-600-2005-010/CEC-600-2005-010-D.PDF). 20 Ideally, similar adjustments would be made for all power plants in state, as well as accounting for specific sources of contracted resources from out of state. However, such complete information is currently lacking. See text below. 21 http://www.cted.wa.gov/site/539/default.aspx Nevada Division of 23 Center for Climate Strategies Environmental Protection www.climatestrategies.us
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Nevada Greenhouse Gas Inventory and Reference Case Projections

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