Chapter 2 – Background: Pacific Northwest Region and Exports to California
The Pacific Northwest region of US includes all of Washington, Oregon, Idaho, part of British Columbia and adjoining parts of Alaska, Montana, Yukon Territory and California. This chapter provides a brief overview of the hydropower sectors in the Pacific Northwest and California regions, and some facts and figures about the scenario of exports to California from the hydro-power dominated Pacific Northwest region.
Hydropower in the Pacific Northwest
Electricity production in the Pacific Northwest (PNW) is dominated by hydropower since the late 1880s, when the first hydropower turbine was installed on a Columbia River tributary. At present (June 2006), the total installed capacity of the region stands at approximately 53,000 MW . Hydropower accounts for about 64% of the total supply capacity in the Pacific Northwest region. Most of the rest comes from coal-fired steam plants and natural gas plants in the region. The region has only one operating nuclear power plant, which accounts for about 2% of the generation capacity. Figs 2.1 and 2.2 provide the percentage breakdown of the total power supply capacity in PNW region by the type of fuel .
Percentage of total supply capacity
Most of the region’s hydroelectric power is generated by the 40-odd major power plants out of the total of 58 dams on the Columbia and Snake rivers . Out of these, 23 major hydropower plants are federal projects; 10 are owned and operated by the Bureau of Reclamation, 13 are owned by the Corps of Engineers and the remaining 17 are owned and operated by local utilities and private companies. Grand Coulee Dam situated on the Columbia River, with installed capacity of approximately 6800 MW, is the largest electric generating facility in the country.
About one-third of the power used in PNW comes from Bonneville Power Administration (BPA), a Federal Agency responsible for marketing power from 31 Federal hydro projects in the Columbia River basin, one non-Federal nuclear plant and several other small non-federal power plants . The combined installed capacity of the 31 hydropower plants stands at 20,460 MW. Hydropower accounts for over 90% of the total generation capacity in BPA territory. 21 plants are owned and operated by the US Army Corps of Engineers (UACE) and the remaining 10 plants by US Bureau of Reclamation (USBR). Some of the major hydroelectric power plants under BPA include Grand Coulee (6,800 MW), Chief Joseph (2,500 MW) and John Day (2,160 MW) -.
The second largest hydropower source in the PNW region is British Columbia Hydro in Canada. British Columbia Hydro (BCH), one of the major exporters of hydro-electric power to California, is the largest utility in the British Columbia province of Canada, serving approximately 95% of the population of British Columbia. Over 90% of power generation in BCH comes from hydro-electric plants . Most of the electricity is produced at the 30 hydroelectric plants, with total capacity of 9,716 MW, on the Columbia and Peace rivers. Between 43,000 and 54,000 GWh of electricity is generated annually depending on the water conditions to meet the demands of the region and the surplus is exported to other regions, including the Southwest US. G.M.Shrum (2,730 MW) and Peace Canyon (700 MW) are the two largest generating stations and are both located on Peace River. They produce about 29% of the BC Hydro’s electricity requirements .
California: Generation mix and Exports from Pacific Northwest
The total installed capacity of California stands at approximately 56,800 MW . The generation mix of California for the year 2007 is shown in Fig 2-5.
The profile of monthly energy generation by fuel type for year 2007 is shown in Fig 2-6 . Natural gas dominates the fuel mix in California power production. Hydro-electric production accounted for less than 12% of total generation in the state. In year 2007, California produced 69% of the electricity it used; 8% was imported from Pacific Northwest and 23% was imported from US southwest (Fig 2-7).
Electricity Generation Mix in California (2007)
The trend of average California annual imports, exports and the net imports for years 2003 through 2007 is shown in Fig 2.8. As depicted in Fig 2.9, the imports continue to play a key role in meeting the demand in California. Majority of the imports from Pacific Northwest region comes from surplus hydro-electric generation in the BPA and the BCH.
Resource Mix percentage of Imports from PNW (2005)
The PNW system is designed to meet all its requirements even in a critically dry hydro year; in all other years it has surplus generation to export to other regions in the WECC. The PNW can’t keep all the surplus hydropower to itself; it’s a winter-peaking region while the peak run-offs occur during the spring. This is in contrast to the summer peaking California region, which benefits from these exports. Shown in Fig 2.10 is the hourly power flows on PNW-CA combined interties for the year 2007 .
PNW-CA Combined Intertie Hourly Flows (2007)
Analysis of the flows show that California imports daily peak power throughout the year from Pacific Northwest region. It imports more power during the spring and summer seasons, when the California system is peaking and the Pacific Northwest loads are low. The power imports are diurnal in nature; with high imports during the on-peak period (16 on-peak hours of the day) and relatively low imports during off-peak periods (8 off-peak hours). California may also export some power during off-peak hours to PNW during the winter seasons.
Almost all of these hydro-electric exports from Pacific Northwest reaches California through two major interties starting from BPA region, collectively called the Pacific Intertie: Pacific AC intertie (PACI) and the Pacific DC intertie (PDCI).
The Pacific AC intertie comprises of three 500 kV AC transmission lines. Its northern portion, which enters the California borders, is called the California Oregon Intertie (COI). The COI is also called Path 66 in California power markets. Two of the 500 kV transmission lines that form the Path 66 originate at Malin substation in BPA region and terminate at the Round Mountain substation in Northern California. The third 500 kV transmission line originates at the Captain Jack substation in BPA, to the west of Malin substation, and terminates at the Olinda substation in Northern California. The AC lines in Oregon are primarily owned by BPA. In California, the AC lines are owned and/or shared between various utilities: PGE, SCE, WAPA, SDGE, SMUD, LADWP and a consortium of other utilities known collectively as the California Oregon Transmission Project (COTP) . The North-to-South transfer capacity of Path 66 is 4,800 MW, out of which 1,600 MW is in the COTP, also known as the Third AC line. The California ISO has contracts to share only 33 MW out of 1,600 MW of COTP transmission capacity
Thus, the total import capacity available to CAISO from path 66 is approximately 3233 MW. The Pacific DC intertie (also called Path 65) consists of a parallel bipolar +/-500 kV DC transmission line, with its northern end at the Celilo Converter station in BPA and southern end at the Sylmar Converter station near Los Angeles. The DC line is owned mostly by BPA in Oregon and equally owned by SCE and LADWP utilities in Southern California . The North-to-South transfer capacity of the DC line is 3100 MW.
All of the trade transactions between British Columbia Hydro and California (or BPA) pass through the BPA region via a major intertie, called the Northern Intertie. The Northern Intertie connects BCH with BPA and it consists of two Ingledow-Cluster 500 kV transmission lines that cross the US-Canadian border at Blaine, Washington and two other transmission lines, Boundary-Nelway 230 kV and Boundary-Waneta 230 kV lines, that cross the border north of Spokane, Washington. The 500 kV lines form the “Western Northern Intertie” while the 230 kV portion forms the “Eastern Northern Intertie” . The Northern Intertie is reserved and scheduled as a single path. The total north-to-south capacity of Northern Intertie is 3100 MW.
CHAPTER 1 – INTRODUCTION
1.1 CONTRIBUTION OF THE WORK
CHAPTER 2 – BACKGROUND: PACIFIC NORTHWEST REGION AND EXPORTS TO CALIFORNIA
2.1 HYDROPOWER IN THE PACIFIC NORTHWEST
2.2 CALIFORNIA: GENERATION MIX AND EXPORTS FROM PACIFIC NORTHWEST
CHAPTER 3 – OVERVIEW OF BOX-JENKINS ARIMA METHODOLOGY: IDENTIFYING BOX-JENKINS MODELS
3. 1 BOX-JENKINS ARIMA MODELS: DEFINITION AND TERMINOLOGY
3.2 STATIONARITY OF TIME SERIES
3.3 STEPS IN ANALYZING DATA AND IDENTIFYING ARIMA MODELS
3.4 FORECASTING USING ARIMA MODELS
3.5 SEASONAL ARIMA MODELS
3.6 ARIMA TRANSFER FUNCTION MODELS
3.7 AIC AND SBC SIMULATIONS
CHAPTER 4 – FORECASTING THE PACIFIC NORTHWEST EXPORTS TO CALIFORNIA
4.1 DEFINITION OF PROBLEM
4.2 SELECTION OF INPUTS
4.3 IDENTIFYING THE FORECASTING MODEL
4.4 DIAGNOSTIC CHECKING OF THE MODEL
4.5 RESULTS OF FITTING
4.6 RESULTS OF FORECASTING
CHAPTER 5 – FORECASTING THE PACIFIC NORTHWEST EXPORTS TO CALIFORNIA -AN ALTERNATE MODEL
5.1 ALTERNATE MODEL FOR FORECASTING THE EXPORTS TO CALIFORNIA
5.2 DIAGNOSTIC CHECKING OF THE MODEL
5.3 RESULTS OF FITTING
5.4 RESULTS OF FORECASTING
CHAPTER 6 – FORECASTING THE POWER EXPORTS TO CALIFORNIA ISO MARKET
6.1 DEFINITION OF PROBLEM
6.2 IDENTIFYING THE FORECASTING MODEL
6.3 DIAGNOSTIC CHECKING OF THE MODEL
6.4 RESULTS OF FITTING
6.5 RESULTS OF FORECASTING
CHAPTER 7 – FORECASTING POWER EXPORTS FROM BRITISH COLUMBIA HYDRO
7.1 DEFINITION OF THE PROBLEM
7.2 IDENTIFYING THE FORECASTING MODEL:
7.3 RESULTS OF FITTING
7.4 RESULTS OF FORECASTING
7.5 POLE-ZERO ANALYSIS OF THE ARIMA FILTER OF FORECASTING MODEL
7.6 OUTLIER DETECTION IN ARIMA FILTER OF THE FORECASTING MODEL
CHAPTER 8- CONCLUSIONS AND FUTURE WORK
GET THE COMPLETE PROJECT
Short-Term Forecasting of Power Flows over Major Pacific Northwestern Interties: Using Box and Jenkins ARIMA Methodology