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Public Interest Energy Research Program: Final Project Report

cover of report Wind Power Generation Trends

Publication Number: CEC-500-2005-181
Publication Date: DECEMBER 2005
PIER Program Area: Renewable Energy Technologies

The executive summary, abstract and table of contents for this report are available below. This publication is available as an Adobe Acrobat Portable Document Format Files. In order to download, read and print PDF files, you will need a copy of the free Acrobat Reader software installed in and configured for your computer. The software can be downloaded from Adobe Systems Incorporated's website.

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Introduction

The importance of wind energy has long been recognized by the California Energy Commission (ENERGY COMMISSION), which supports research and development in renewable energy including wind through its Public Interest Energy Research (PIER) Program. Wind energy provides significant benefits in terms of improved air quality, increased diversity in electric energy sources, local and state revenues, and employment. Still, wind energy development in California faces a large number of minor and major impediments.

In an effort to foster additional development of wind energy in the state, the ENERGY COMMISSION created the California Wind Energy Consortium (CWEC), which is managed by the University of California at Davis. The mission statement of the California Wind Energy Consortium (the Consortium) is to support the development of safe, reliable, environmentally sound, and affordable wind electric generation capacity within the state of California. To fulfill this mission, the Consortium will manage a focused, statewide program of scientific research, technology development and deployment, and technical training. The effort is conducted in close cooperation with industry, state and federal agencies, and other institutions to maximize the benefits of wind energy resources in California for its citizens.

Wind Turbine Generator Optimization

One of the Consortium’s first assignments was a series of white papers, whose purpose was to review the performance of wind turbines in typical operating environments. Wind turbine power generation characteristics are affected by a wide range of factors including: seasonal changes in air density, blade soiling (insect debris, dust, etc.), control system interactions with turbulent winds, maintenance procedures, and connection issues to the electrical transmission system. These factors impact both the cost and the value of wind power production. The goal of this effort is to evaluate performance issues and identify methods and procedures for maximizing wind energy generation and value.

Three topic areas were identified for the white papers:

  1. Daily wind power generation trends
  2. Optimization of wind turbine peak capacities
  3. Transmission interconnection issues and standards

This report includes data evaluations, commentary, and review in the first two topic areas. The goal of this effort was to establish a sense for the variations in wind power generation in California and assess the change in these levels according to the time of day and the season of the year. Representative wind data was obtained and adjusted to standard air density. This data was then used to determine the power output of three representative 1 MW wind turbines with different rotor sizes: 50 meter diameter, 70 m diameter, and 90 meter diameter. The output from these turbines was compared against the statewide system electrical demand and trends were observed.


Abstract

This report includes data evaluations, commentary, and review of daily wind power generation trends an d optimization of wind turbine peak capacities in California. The goal of this effort was to establish a sense for the variations in wind power generation in California and assess the change in these levels according to the time of day and the season of the year. Representative wind data was obtained and adjusted to standard air density. This data was then used to determine the power output of three representative 1 MW wind turbines with different rotor sizes: 50 meter diameter, 70 m diameter, and 90 meter diameter. The output from these turbines was compared against the statewide system electrical demand and trends were observed.



Table of Contents

1.0 INTRODUCTION 1

1.1 California Wind Energy Consortium 1

1.2 Wind Turbine Generator Optimization 1

2.0 WIND TURBINE GENERATOR DESCRIPTION 2

2.1 Wind Generator Technology Overview 2

2.2 Turbine Performance Model 4

3.0 POWER GENERATION AND DEMAND 9

3.1 Yearly Wind Power Generation 9

3.2 Diurnal Generation Patterns 11

3.3 Statewide Power Demand 13

3.4 Peak Demand Periods 16

3.5 Diurnal Marginal Capacity 21

4.0 POWER VALUE AND REVENUES 23

4.1 Time Dependent Valuation of Electricity 23

4.2 Wind Generation Revenue 24

5.0 SUMMARY 26

5.1 Conclusions 26

5.2 Recommendations 27


LIST OF TABLES

Table 2.1 Specific Power of Selected Wind Turbines 4

Table 2.2 Specific Power of Model Wind Turbines 5

Table 2.3 Blade Planform Definition 6

Table 2.4 Summary of Rotor Non-Dimensional Performance 7

Table 2.5 Summary of Turbine Rotor Properties 7

Table 2.6 Drive Train Efficiency Model 8

Table 2.7 Turbine Power Output as a Function of Wind Speed 8

Table 2.8 Turbine Capacity Factor as a Function of Wind Speed 11

Table 3.1 Top Ten Peak Demand Days of 2001 17

Table 4.1 Summary of Average Annual TDV Revenue Factors 26

Table 4.2 Comparison of Constant Value and TDV Revenue Factors 26


LIST OF FIGURES

Figure 2.1 Rotor Diameter of Model Wind Turbines 5

Figure 2.2 Specific Power as a Function of Rated Power for Existing Turbines and Model Turbines 5

Figure 2.3 Blade Planform Drawing 6

Figure 2.4 Turbine Power Curve Comparison 8

Figure 3.1 First Quarter 2001 Power Generation at the 7 m/s Site 10

Figure 3.2 Second Quarter 2001 Power Generation at the 7 m/s Site 10

Figure 3.3 Third Quarter 2001 Power Generation at the 7 m/s Site 10

Figure 3.4 Fourth Quarter 2001 Power Generation at the 7 m/s Site 10

Figure 3.5 Turbine Average Annual Capacity Factor as a Function of Wind Speed and Rotor Diameter 11

Figure 3.6 March, April, November, and December Daily Capacity Factor for the 70 m Turbine and 7 m/s Wind Speed 12

Figure 3.7 January, February, September, and October Daily Capacity Factor for the 70 m Turbine and 7 m/s Wind Speed 12

Figure 3.8 May, June, July, and August Daily Capacity Factor for the 70 m Turbine and 7 m/s Wind Speed 13

Figure 3.9 First Quarter 2001 Power Demand 14

Figure 3.10 Second Quarter 2001 Power Demand 14

Figure 3.11 Third Quarter 2001 Power Demand 14

Figure 3.12 Fourth Quarter 2001 Power Demand 14

Figure 3.13 First Quarter 2001 Average Daily Demand Factor 15

Figure 3.14 Second Quarter 2001 Average Daily Demand 15

Figure 3.15 Third Quarter 2001 Average Daily Demand 16

Figure 3.16 Fourth Quarter 2001 Average Daily Demand 16

Figure 3.17 Turbine Capacity and Statewide Demand During a Summer Peak Period at the 6 m/s Reference Site 17

Figure 3.18 Turbine Capacity and Statewide Demand During a Summer Peak Period at the 7 m/s Reference Site 17

Figure 3.19 Turbine Capacity and Statewide Demand During a Summer Peak Period at the 8 m/s Reference Site 18

Figure 3.20 Turbine Capacity and Statewide Demand During a Summer Non-Peak Period at the 6 m/s Reference Site 18

Figure 3.21 Turbine Capacity and Statewide Demand During a Summer Non-Peak Period at the 7 m/s Reference Site 18

Figure 3.22 Turbine Capacity and Statewide Demand During a Summer Non-Peak Period at the 8 m/s Reference Site 19

Figure 3.23 Average Capacity Factor as a Function of Demand Factor at the 6 m/s Reference Site 19

Figure 3.24 Average Capacity Factor as a Function of Demand Factor at the 7 m/s Reference Site 19

Figure 3.25 Average Capacity Factor as a Function of Demand Factor at the 8 m/s Reference Site 20

Figure 3.26 Average Capacity Factor as a Function of Demand Factor for the 7 m/s Reference Site 20

Figure 3.26 First Quarter 2001 Marginal Capacity of the 70 m Turbine at the 7 m/s Reference Site 21

Figure 3.27 Second Quarter 2001 Marginal Capacity of the 70 m Turbine at the 7 m/s Reference Site 21

Figure 3.28 Third Quarter 2001 Marginal Capacity of the 70 m Turbine at the 7 m/s Reference Site 22

Figure 3.29 Fourth Quarter 2001 Marginal Capacity of the 70 m Turbine at the 7 m/s Reference Site 22

Figure 3.30 Comparison of August 2001 Marginal Capacity at the 7 m/s Reference Site 23

Figure 4.1 Mojave Commercial Electricity Value Factor 24

Figure 4.2 Capacity Factor and Electricity Value Factor During a Summer Peak Period at the 7 m/s Reference Site 24

Figure 4.3 Revenue Factor and Capacity Factor During a Summer Peak Period at the 7 m/s Reference Site 25

Figure 4.4 Revenue Factor and Capacity Factor During a Summer Non-Peak Period at the 7 m/s Reference Site 25


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