Post on 13-Jan-2016
Transmission and Wind Integration
June 7, 2010
Michael Goggin
American Wind Energy Association
Outline
● Benefits of Wind Energy● Transmission Overview● Wind Integration Overview
Over 500,000 Total Jobs Supported By Wind In DOE report
Fact: in 2008, 35,000 new jobs added
Currently Installed MW by State
DOE 20% Report Scenario: 46 States Could Have Major Wind Development by 2030
Incremental direct cost to society
$43 billion
50 cents/month/
household
Reduction in emissions of greenhouse gasses and avoided carbon regulation costs
825 million tons of CO2
$50 to $145 billion
Reduction in water consumption 8% through 2030
17% in 2030
Jobs supported and other economic benefits
500,000 total with 150,000 direct jobs
$2 billion in local annual revenues
Reduction in nationwide natural gas use and savings for all gas consumers
11%
$86-214 billion
DOE 20% Report Summary: Costs & Benefits
Sources: DOE, 2008 and Hand et al., 2008 Note: All dollar values are in NPV
Transmission
● How a Lack of Transmission Hurts Renewables:• Renewable projects cannot connect to the grid• Project output can be curtailed because of inadequate
transmission• Cannot capture benefits of geographically diverse
resources● Transmission Needed Anyway to Reduce Congestion and
Improve Reliability• Consumers losing $10s of billions per year due to
transmission congestion and inefficiency• Reliability events cost consumers billions per year • Nearly every source of new generation will need new
transmission
The Lack of Transmission is a Major Problem
Iowa17,639
Minnesota18,203
New Mexico18,007
North Dakota12,602
Penn.2,935
South Dakota27,806
Oklahoma10,187
Illinois17,086
Ohio3,810
Kansas9,433
Wisconsin628
Michigan3,242
WV818
New York6,990
VT236
Total 297,808 MW
MA520
Montana5,694
NJ704
Under 1000 MW
1,000 MW-8,000 MW
Over 8,000 MW
Missouri5,411
Indiana8,225
Maine1,866
NH 496
RI949
DE450
MD100
VA83
Arkansas60
Texas50,669
3,994
California11,575
Colorado15,904
Idaho730
Nebraska2,690
Nevada4,099
Oregon14,336
Utah1,349
Washington8,702
Wyoming9,582
Wind in Interconnection Queues by State
AWEA calculation as of March 16, 2010
Economies of Scale for High-Capacity Transmission
Source:MISO
4.56.66.92.6*Cost/Mile ($M) for 2400 MW capacity
172110124132Typical Height (ft)
44%22%38%100%ROW utilization
factor
450900600200Total ROW (ft)
150150200200ROW per line (ft)
3631Lines Required for 2400 MW Capacity
8004009102400SIL per Line (MW)
2236Conductors/Phase
2111Circuits/Tower
345345500765Description
4.56.66.92.6*Cost/Mile ($M) for 2400 MW capacity
172110124132Typical Height (ft)
44%22%38%100%ROW utilization
factor
450900600200Total ROW (ft)
150150200200ROW per line (ft)
3631Lines Required for 2400 MW Capacity
8004009102400SIL per Line (MW)
2236Conductors/Phase
2111Circuits/Tower
345345500765Description
•* Cost in 2006 $US, based on average terrain
•** SIL is a relative capacity measure, thermal capacity is ~4000 MW for 765 kV and ~ 2000 MW for 500 kV
•
765-kV benefits are substantial over 500-kV and 345-kV.
765-kV benefits are substantial over 500-kV and 345-kV.
Transmission voltage selection significantly affects performance, cost
and the environment.
Transmission voltage selection significantly affects performance, cost
and the environment.
•* Cost in 2007 $US, based on average terrain.•** SIL is a relative capacity measure, thermal capacity is over 4000 MW for 765 kV and ~ 2000 MW for 500 kV.
•
Source: AEP
Reduced Land Use
The Market Failures● Economic benefits of transmission do outweigh costs:
• Joint Coordinated System Plan: Would pay for itself in 7 years by reducing power prices
• Texas study: Would pay for itself in 3 years• Reliability benefits• Reduction in fuel price volatility impacts• Benefits of connected renewables: environmental,
economic development, energy security
● Why don’t we just build the transmission? - Obsolete transmission policies, particularly cost
allocation policies- In many regions, current cost allocation policy is analogous to charging the next truck entering a congested highway the full cost of adding a new lane
● Policy reforms needed to allow new transmission construction to proceed:• Planning (pro-active planning)• Paying (broad regional cost allocation)• Permitting (streamlined siting)
● AWEA-SEIA white paper at http://www.awea.org/
GreenPowerSuperhighways.pdf
Policy Reform Needed: The Three P’s
Wind Integration
2009 U.S. Wind Penetration
Source: AWEA data, EIA forms 906 and 920, 2008 data
European Wind Energy Penetration, 2008
21.22%
11.76%
9.26%
8.42%
7.00%
4.28%
3.89%
3.78%
3.67%
3.40%
3.28%
1.82%
0.00% 5.00% 10.00% 15.00% 20.00% 25.00%
Denmark
Spain
Portugal
Ireland
Germany
EU-15
EU-25
EU-27
Greece
Netherlands
Austria
UK
Source: EWEA 2007 and Eurelectic 2006
Power System Operations:Background
● Electricity supply and demand must match at all times
● Grid operators accomplish this by increasing and decreasing the output of flexible generators, like hydroelectric and natural gas power plants
● Electricity demand is highly variable; forecasts are used, but there is still variability and uncertainty
● Electricity supply is also variable and uncertain● As a result, grid operators hold generation in reserve
to accommodate aggregate variability:• Regulation reserves • Load-following reserves • Contingency reserves
● Reserves can be spinning or non-spinning
Source: NREL
The Flexibility Supply Curve
The Distance Element of Wind’s Variability
Correlation in plant output as a function of time and distance
Source: NREL
The Time Element of Wind’s Variability
StudyWind Penetration 1 minute 5 minute 1 hour
Texas 2008[1] 15,000 MW 6.5 MW 30 MW 328 MW
California Energy Commission 2007[2]
2,100 MW, +330MW solar 0.1 MW 0.3 MW 15 MW
7,500 MW, +1,900 MW solar
1.6 MW 7 MW 48 MW
12,500 MW, +2,600 MW solar
3.3 MW 14.2 MW 129 MW
New York 2005[3]
3,300 MW - - 1.8 MW 52 MW
[1] http://www.uwig.org/Wind_Generation_Impact_on_Ancillary_Services_-_GE_Study.zip[2] http://www.uwig.org/CEC-500-2007-081-APB.pdf[3] http://www.uwig.org/nyserdaphase2appendices.pdf
Wind Integration CostsDate Study Wind
Capacity Penetration (%)
Regulation Cost ($/MWh)
Load Following Cost ($/MWh)
Unit Commitment Cost ($/MWh)
GasSupplyCost($/MWh)
Total Operating Cost Impact($/MWh)
May ‘03 Xcel-UWIG 3.5 0 0.41 1.44 na 1.85
Sep ‘04 Xcel-MNDOC 15 0.23 na 4.37 na 4.60
June ‘06 CA RPS 4 0.45* trace na na 0.45
Feb ‘07 GE/Pier/CAIAP 20 0-0.69 trace na*** na 0-0.69***
June ‘03 We Energies 4 1.12 0.09 0.69 na 1.90
June ‘03 We Energies 29 1.02 0.15 1.75 na 2.92
2005 PacifiCorp 20 0 1.6 3.0 na 4.60
April ‘06 Xcel-PSCo 10 0.20 na 2.26 1.26 3.72
April ‘06 Xcel-PSCo 15 0.20 na 3.32 1.45 4.97
Dec ’08 Xcel-PSCo 20 3.95 1.18 5.13-6.30****
Dec ‘06 MN 20% 31** 4.41**
Jul ‘07 APS 14.8 0.37 2.65 1.06 na 4.08
Source: NREL
Lessons Learned from Wind Integration Studies
● Wind forecasting can significantly reduce integration costs by reducing uncertainty
● Geographically diverse wind resources tend to be less variable● Wind resources spread over larger areas are less variable –
one of the reasons why transmission is important● Diverse wind has very little variability on the minute-to-minute
time scale● Wind is easier to integrate on more flexible power systems ● Market/system operation reforms can significantly reduce wind
integration costs● A robust transmission grid can significantly reduce integration
costs● Integrating wind is a cost issue, not a reliability issue (thinking
about “limits” or renewable thresholds is inaccurate) ● Storage is not needed, but can help
Solutions: Transmission is Critical
● NERC IVGTF: “Transmission expansion, including greater connectivity between balancing areas, and coordination on a broader regional basis, is a tool which can aggregate variable generators leading to the reduction of overall variability. Sufficient transmission capacity serves to blend and smooth the output of individual variable and conventional generation plants across a broader geographical region. Large balancing areas or participation in wider-area balancing management may be needed to enable high levels of variable resources.” (p. 43)
• NERC: “More frequent and shorter scheduling intervals for energy transactions may assist in the large-scale integration of variable generation.” (p. 61)
• In much of the U.S., power plants are scheduled to operate for hourly intervals, and expensive reserves are used to accommodate intra-hour variability
• Using 5- or 10-minute scheduling intervals accommodates intra-hour variability without reserves
• Studies show significant savings from moving to 5- or 10-minute intervals instead of hourly:• Bonneville Power: 80% reduction in wind integration costs• Avista: 40-60% reduction in wind integration costs
Shorten Power Plant Dispatch Intervals
Flexibility through markets
● NERC: “Additional sources of system flexibility include the operation of structured markets, shorter scheduling intervals, demand-side management, reservoir hydro systems, gas storage and energy storage.” (p. 48)
● Ancillary services markets provide incentives for generators, demand response, and other flexible resources to offer their services to the grid
● Markets ensure that lowest-cost resources provide needed flexibility services
Larger Balancing Areas
• Allow excess power in one region to be shared with neighboring regions
• Enable diverse wind resources spread over a larger area to be connected to the same grid, canceling out their variability
• Create cost savings
• Midwest ISO estimates savings from consolidating its 26 balancing areas into one are 3.7 to 6.7 times greater than the costs
• Savings are large even on power systems without wind energy
• Consolidation can be done physically or virtually
Grid Balkanization Impairs Wind Integration
• NERC: “Forecasting is one of the key tools needed to increase the operator’s awareness of wind plant output uncertainty and assist the operator in managing this uncertainty.” (p. 55)
• Largest opportunities for improvement:
• Better integrating forecasts into power system operations
• Faster updating short-term models, more data
Improve Use of Wind Forecasting