US Wind Energy Growth: Issues for 20% by 2030

Introduction to EE 551January 12, 2009

James D. McCalleyProfessor of Electrical and

Computer Engineering

Outline1. Electric industry overview2. What is a wind plant?3. Problems with wind; potential solutions4. Other technology options5. National investment planning6. Conclusions

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

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• Investor-owned utilities: 239 (MEC, Alliant, Xcel, Exelon, …)• Federally-owned: 10 (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 (ISO-NE, NYISO, PJM, MISO, SPP, ERCOT, CAISO, AESO, NBSO)

• 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

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1. Electric Industry Overview: Legislative Landscape

• Carbon policy:• Obama admin favors cap ‘n trade• Existing models: SO2, 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• FERC’s authority - national interest corridors• Alternative: >3 states band (Uppr Mdwst Trns Dvlpmnt Initiative)

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

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1. Electric Industry Overview: 20% by 2030

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

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2. What is a wind plant?Overview

2. What is a wind plant?Tower & Blades

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Manu-facturer

Capacity Hub Height

Rotor Diameter

0.5 MW 50 m 40 m

GE 1.5 MW 61-100 70.5-77 m

Vestas 1.65 MW 70,80 m 82 m

Clipper 2.5 MW 80m 89-100m

GE 2.5 MW 75-100m 100 m

Vestas 3.0 MW 90m 80, 105m

Acciona 3.0 MW 100-120m 100-116m

GE 3.6 MW 104 m

Siemens 3.6 MW 107m

Gamesa 4.5 MW 128 m

REpower 5.0 MW 126 m

Enercon 6.0 MW 135 m 126 m

Weight (Vestas 1.65MW)

Nacelle: 57 s-tonsRotor: 47 s-tonsTower: 138 s-tons

2. What is a wind plant?Electric Generator

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generator

full power

PlantFeeders

actodc

dctoac

generator

partia l power

PlantFeeders

actodc

dctoac

generator

Slip poweras heat loss

PlantFeeders

PF controlcapacitor s

actodc

generator

PlantFeeders

PF controlcapacitor s

Type 1Conventional Induction Generator (fixed speed)

Type 2Wound-rotor Induction

Generator w/variable rotor resistance

Type 3Doubly-Fed Induction

Generator (variable speed)

Type 4Full-converter interface

2. What is a wind plant?Type 3 Doubly Fed Induction Generator

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generator

partia l power

PlantFeeders

actodc

dctoac

• 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

2. What is a wind plant?Collector Circuit

• Distribution system, often 34.5 kV

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POI or connection to the grid Collector System

Station

Feeders and Laterals (overhead and/or underground)

Individual WTGs

Interconnection Transmission Line

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

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3. Problems with wind; potential solutionsCost

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3. Problems with wind; potential solutionsCost

•$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 MW20-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

3. Problems with wind; potential solutionsDay-ahead forecast uncertainty

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

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Hourly Load Variability and Load-Wind Variability When Wind Penetration is 10%

0

500

1000

1500

2000

2500

3000

3500

4000

-800

-700

-600

-500

-400

-300

-200

-100

0 100

200

300

400

500

600

700

800

Load and Load-Wind Hourly Variability (MW)

Fre

qen

cy

Load Hourly Variability Load-Wind Hourly Variability

Solutions:• 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

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

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Solutions:• “Spill” wind• Shift loads in time• Storage

• Pumped storage• Pluggable hybrid vehicles• Batteries• H2, NH3 with fuel cell• Compressed air• …others

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

Midwestern Region

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

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

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Build transmission! $60 billion AEP plan

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

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Build transmission! $80 billion JCSP plan

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

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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.

4. Other technology options

• Energy sourcesNatural 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

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

At 810 Gw load, 1.5% growth, we need 660 Gw over next 40 years. What do we invest in?

4. Other technology options

GEOTHERMALSOLAR

WindBIOMASS

CLEAN-FOSSIL

NUCLEAR

But how much of each, & how to interconnect?

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

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Conclusions

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• 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