Introduction to EE 551 January 12, 2009

US Wind Energy Growth: Issues for 20% by 2030

James D. McCalley Professor of Electrical and Computer Engineering

Outline

1. Electric industry overview 2. What is a wind plant?

3. Problems with wind; potential solutions 4. Other technology options 5. National investment planning 6. Conclusions

• • • • • • • •

1. Electric Industry Overview: Organizational Structure (N. America)

Investor-owned utilities: 239 Federally-owned: 10 (MEC, Alliant, Xcel, Exelon, …) (TVA, BPA, WAPA, SEPA, APA, SWPA…) Public-owned: 2009 (Ames, Cedar Falls, Dairyland, CIPCO…) Non-utility power producers: 1934 (Alcoa, DuPont,…) Power marketers: 400 (e.g., Cinergy, Mirant, Illinova, Shell Energy, PECO-Power Team, Williams Energy,…) Coordination organizations: 10 SPP, ERCOT, CAISO, AESO, NBSO) (ISO-NE, NYISO, PJM, MISO, Oversight organizations: • • Regulatory: 52 state, 1 Fed (FERC) Reliability: 1 National (NERC), 8 regional entities Others: Manufacturers, vendors, govt agencies, professional & advocacy organizations…

1. Electric Industry Overview: Existing resource mix; Retail Prices

4

1. Electric Industry Overview: Legislative Landscape

• Carbon policy: • Obama admin favors cap ‘n trade • Existing models: SO

2 , RGGI ($3.5/ton), EU

• Coal plnt: $3.50/ton×0.925tons/MWhr=$3.2/MWhr=0.3¢/kWhr • Subsidies: • Fed PTC, REPI (must have renewals - last done 10/08), 2¢/kWhr • State PTC (IA: 1.5¢/kWhr, small wind, UT, OK), sales/prop tax red • Renewable portfolio standards (RPS)

32 states, differing in % (10-30), timing (latest is 2025), eligible technologies/resources (all include wind)

• Building transmission • Multi-state transmission is very difficult • Alternative: >3 states band (Uppr Mdwst Trns Dvlpmnt Initiative)

1. Electric Industry Overview: Predicted (US EIA, NEMS); May ’07

6

1. Electric Industry Overview: 20% by 2030

• 5/08: www1.eere.energy.gov/windandhydro/ • The report identifies what this future looks like 7

2. What is a wind plant?

Overview

Manu facturer 2. What is a wind plant?

Capacity Tower & Blades Hub Height Rotor Diameter

0.5 MW 1.5 MW 50 m 61-100 40 m 70.5-77 m GE Vestas Clipper GE Vestas Acciona 1.65 MW 2.5 MW 2.5 MW 3.0 MW 3.0 MW GE Siemens Gamesa 4.5 MW REpower 5.0 MW Enercon 3.6 MW 3.6 MW 6.0 MW 70,80 m 80m 75-100m 90m 100-120m 135 m 82 m 89-100m 100 m 80, 105m 100-116m 104 m 107m 128 m 126 m 126 m Weight (Vestas 1.65MW) Nacelle: 57 s-tons Rotor: 47 s-tons Tower: 138 s-tons 9

2. What is a wind plant?

Electric Generator Type 1 Conventional Induction Generator (fixed speed)

gene rator

Type 2 Wound-rotor Induction Generator w/variable rotor resistance

gene rator Slip power as heat loss ac to dc Plant Feeders PF control capacitor s Pla nt Fee ders PF control capacitor s

Type 3 Doubly-Fed Induction Generator (variable speed)

gene rator ac to dc dc to ac Plant Feeders

Type 4 Full-converter interface

10 partia l power generator ac to dc dc to ac Plant Feeders full power

2. What is a wind plant?

Type 3 Doubly Fed Induction Generator

• Most common technology today • Provides variable speed via rotor freq control • Converter rating only 1/3 of full power rating • Eliminates wind gust-induced power spikes • More efficient over wide wind speed • Provides voltage control Plant Feeders gene rator ac to dc dc to ac 11 partia l power

2. What is a wind plant?

Collector Circuit

• Distribution system, often 34.5 kV

POI or connection to the grid Interconnection Transmission Line Collector System Station

12

Feeders and Laterals (overhead and/or underground) Individual WTGs

2. What is a wind plant?

Offshore

• About 600 GW available 5-50 mile range • About 50 GW available in <30m water • Installed cost ~$2500/MW; uncertain

because US cont. shelf deeper than N. Sea

13

3. Problems with wind; potential solutions Cost

3. Problems with wind; potential solutions Cost •$1050/kW capital cost • 34% capacity factor • 50-50 capital structure • 7% debt cost; 12.2% eqty rtrn • 20-year depreciation life • $25,000 annual O & M per MW



20-year levlzd cost=5¢/kWhr • Existing coal: <2.5¢/kWhr • Existing Nuclear: <3.0¢/kWhr • New gas combined cycle: >6.0¢/kWhr • New gas combustion turbine: >10¢/kWhr Solution:

• Cost of wind reduces as tower height increases • Tower designs, nacelle weight reduction, innovative constructn • Carbon cost makes wind good (best?) option 15

3. Problems with wind; potential solutions Day-ahead forecast uncertainty

• Fossil-generation is planned day-ahead • Fossil costs minimized if real time same as plan • Wind increases day-ahead forecast uncertainty

Solutions:

4000 3500 3000 2500 2000 1500 1000 500 0

Hourly Load Variability and Load-Wind Variability When Wind Penetration is 10% Load and Load-Wind Hourly Variability (MW)

• Pay increased fossil costs from

fossil energy displaced by wind

• Use fast ramping gen • Distribute wind gen widely • Improve forecasting • Smooth wind plant output • On-site regulation gen • Storage 16 Load Hourly Variability Load-Wind Hourly Variability

3. Problems with wind; potential solutions Daily, annual wind peak antiphase w/load

• Daily wind peaks may occur at night • Annual wind peaks may occur in winter

Midwestern Region Solutions:

• “Spill” wind • Shift loads in time 17 • Storage • Pumped storage • Pluggable hybrid vehicles • Batteries • H

2 , NH 3 with fuel cell

• Compressed air • …others

3. Problems with wind; potential solutions Wind is remote from load centers

18

3. Problems with wind; potential solutions Wind is remote from load centers



Build transmission!

$60 billion AEP plan

19

3. Problems with wind; potential solutions Wind is remote from load centers



Build transmission!

$80 billion JCSP plan

20

3. Problems with wind; potential solutions Wind is remote from load centers Transmission cost: a small fraction of total investment & operating costs.

…And it can pay for itself:

• Assume $80B provides 20,000 MW

delivery system over 30 years, 70% capacity factor, for Midwest wind energy to east coast.

• This adds $21/MWh. • Cost of Midwest energy is $65/MWh. • Delivered cost of energy would then

be $86/MWh.

•East coast cost is $110/MWh. 21

20% Wind Future Cumulative Costs through 2024

30% Production 2% Generation Capital 68% Transmission Capital

4. Other technology options

• Energy sources

Natural gas, clean coal, nuclear, biomass, biofuel, solar, deep geothermal, ocean, off-shore wind

• Small generation and demand side control • Other carrier technologies

pipeline (natural gas, liquid fuel) , rail/highway, H2, NH3 At 810 Gw load, 1.5% growth, we need 660 Gw over next 40 years. What do we invest in?

Observation: some energy sources are more economic in certain regions than others….

22

4. Other technology options SOLAR CLEAN-FOSSIL GEOTHERMAL But how much of each, & how to BIOMASS Wind

5. National investment planning

• A new level of energy planning • All energy forms can be used in electric or in transportation • Solution space is temporal (40 yrs), spatial (nation), and … • Multiobjective: 

Min cost, max sustainability, max resiliency

• Appropriate tools do not exist today • Approach:

Very fast multiobjective optimization

• Network flow modeling • Decomposition methods • High-performance computing 24

Conclusions

• Greenhouse gas has made energy top US priority,

and Obama administration is poised to act

• Energy and transportation infrastructure are

capital intensive and very long-lifed

• An intense need for infrastructure planning tools • No silver bullet; no technology should be zeroed • But wind clearly has a large role to play • Must address variability, antiphase peaks, and

transmission needs

• Iowa well located to play major role in this work 25