A REVIEW OF LARGE-SCALE RENEWABLE ELECTRICITY INTEGRATION STUDIES Paulina Jaramillo, Carnegie Mellon University And Paul Hines, University of Vermont
Dec 21, 2015
A REVIEW OF LARGE-SCALE RENEWABLE ELECTRICITY
INTEGRATION STUDIES
Paulina Jaramillo, Carnegie Mellon University
And
Paul Hines, University of Vermont
Introduction• 33 States have developed
Renewable Portfolio Standards
• Many RPS call for large percentages (~20%) of Renewable electricity
• Wind is the fastest growing renewable source
• Wind: Intermittent and Variable
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0
10
20
30
40
50
60
Bill
ion
kWh
USA Wind Production
www.renewelec.org
Integration Studies
• Several recent studies evaluate the impacts of renewables on grid operations, and identify strategies to mitigate these impacts.
• We performed a systematic review of recent integration studies, focusing on wind
Goals of our review• What grid, wind data
were used?• Evaluate methodology for
estimating– Wind power variation– Reserves requirements– Regulation requirements
• Identify research gaps
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NYSERDA 2005• 3,300 MW of Wind in New York State.• The analysis separates among different time
scales.• Brief analysis of forecast value.• Main recommendation: Wind farms build voltage
controls and low voltage ride through capability. • Major Concern: Use of Gaussian methods for
reserve calculations– Conclusions based largely on measured standard
deviation and mean
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Real wind data, 31% CF, Std. Dev. ΔP = 21 MW
Gaussian data, 31% CF, Std. Dev. ΔP = 21 MW
Empirical comparison of real wind data and “Normal” wind data
The Gaussian assumption dramatically underestimates the probability of multiple sequential large changes in the same direction.
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2006 Minnesota Wind Integration Study
• 15%, 20%, and 25% wind integration in MISO for the year 2020.
• Conclusion:– Penalty for variability between $2 and $4 per MWh.– Increasing spatial diversity reduces the number of
“no-wind power” events, reserves requirements.
• Concerns:– Gaussian methods for reserves calculations.– Analysis gap for short term modeling.
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2007 CAISO Wind Integration Study
• Modeled theoretical wind plants in California and identified transmission requirements.
• Conclusion:– Using Types 3 and 4 turbines will allow for reliable
wind integration.
• Concern:– Use of Gaussian methods for reserve calculations.
2008 NREL’s 20% Wind by 2020
• Not really an integration study, but a projection of technology and economic requirements to achieve 20% wind by 2030.
• Good comparison of available wind power at various wind speed class levels.
• Recommendation: Build transmission
• Concern: Transmission system modeling not based on Kirchhoff’s & Ohm’s laws
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2008 ERCOT Wind Integration
• Analysis of impact of wind generation on net load.
• Conclusions:– Wind AND load are variable and out-of-phase.– Seasonal variations exist.– Reserve and regulation requirements increase with
increased wind power.
• Concern:– Use of Gaussian methods for reserve calculations.– No grid model.
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2009 Trade Wind Integration Study - Europe
• Study focused on transmission flows to identify transmission needs.
• Assumes that regional diversity is sufficient to deal with the variability of wind power.
• No discussion about reliability and reserves.
• Potentially erroneous finding: “Wind and Load are positively correlated.”
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2010 Eastern Wind Integration and Transmission Study
• 4 different scenarios with different percentage of wind generation and different wind production locations.
• Use of DC power flow model allows them to identify transmission investment that will be needed at larger wind generation percentages.
• Estimated reserved requirements, forecast error, curtailment and impacts of geographic diversity.
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2010 SW Power Pool (CRA)
• Study 10%, 20% and (limited) 40% wind penetration.
• Detailed contingency study.
• Based on hourly and limited high-resolution data.
• Conclude that no additional contingency reserves needed.
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2010 CEC/KEMA study of reserves and regulation
• Analyze 20% and 33% renewable scenarios.
• First large-scale study to include dynamic generator models.
• Conclude that fast-ramping storage is needed to manage ACE and frequency deviations.
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2010 studies by NERC, CAISONERC analysis of renewables & reliability
• Qualitative study of reliability risks, given renewables, DSM, storage
• Emphasize the need for more load-following during morning and evening ramps
• New technology will require changes to operating policies.
CAISO analysis of 20% renewable in 2012 (PNNL)
• 1-minute wind data data
• Monte-Carlo model to model forecasts
• Regulation estimates based on 1-minute data
• One of the most careful studies reviewed (but still use standard deviations)
• Emphasize need to better understand load-following in morning/evening.
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Research gaps
• Gaussian statistical methods Frequently conclusions are drawn from the mean and standard deviation of sampled wind data. – Need better models.
• Larger control areas Several studies conclude that aggregating control areas reduces costs. – Further analysis needed.
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Research gaps
• Meteorological vs. anemometer data – Need empirical research to find the appropriate role
for each.
• Estimation of regulation requirements– Need new methods, for estimating regulation needs,
given accurate wind and solar data.
• Morning and evening ramping– Wind and load are generally anti-correlated during the
morning and evening. Need new operating policies and technology
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