The Maturing Solar Marketplace: Technology, Policy, and Business Models Adam Warren, PhD US Department of Energy’s National Renewable Energy Laboratory (NREL)
NREL Overview o
Nearly 1,700 employees, annual budget of ~$400M
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~650 active partnerships with industry, academia, and government
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Owned by US Department of Energy, operated by non-profit, the Alliance for Sustainable Energy LLC
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Hardware in the Loop: Test hardware at scale with real-time feedback from operating or modeled systems
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Peregrine HPC: Modeling and simulation of complex, dynamic techno-economic systems
Energy System Integration Facility (< 1 MW)
National Wind Technology Center (<7 MW)
Why Islands? Islands are uniquely situated to develop and demonstrate the integrated energy solutions at scale. • High energy costs • Political will to change • Excellent renewable energy resources • Smaller, weaker grids
Islands are “Postcards from the Future” – Hawaii DBEDT Director, Ted Liu
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Achieving a transformed energy system
Policy
Technology
People / Stakeholders
Market
Two Solar PV Examples â&#x20AC;˘ Distributed Generation in Hawaii â&#x20AC;˘ Utility-scale Solar PV in Puerto Rico
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The transformation of the power sector is underway
â&#x20AC;&#x153;Swanson's Lawâ&#x20AC;?: The price of solar PV modules tends to drop 20 percent for every doubling of cumulative shipped volume
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So how do we deal with all of this variable, uncertain, non-dispatchable sources of clean energy?
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The Basics â&#x20AC;˘ An AC electrical system must maintain several important characteristics of the power. Chief among these are voltage and frequency. â&#x20AC;˘ There is almost no storage on most grids. All generators and loads on a grid work together to keep the grid operational. Therefore, load and generation must be balanced in real-time.
Frequency
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Frequency drops with Demand > Generation
Under-frequency load shedding occurs with the frequency drops below 59.3 Hz (in the US) http://ccc.centers.ufl.edu/sites/default/files/files/background.pdf 8
Achieving a transformed energy system
Policy
Technology
People
Market
Two Solar PV Examples â&#x20AC;˘ Distributed Generation in Hawaii â&#x20AC;˘ Utility-scale Solar PV in Puerto Rico
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PREPA Power System
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PREPA Frequency Response Example
• Lower inertia compared to large power systems • Limited primary frequency response
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Typcial Frequency Response by Synchronous Generators
Can PV generation provide similar Frequency Response? 12
Utility-Scale ‘Smart’ PV Plant Components
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Tests for Ilumina PV plant • PV Plant participation in AGC o
Follow PREPA AGC signal within 40% of available power
• Plant providing frequency droop response o
Both up and downregulation
• Fast Frequency Response (FFR) tests o
Test plant’s ability to deploy all reserve within 500 ms
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Available Power Estimation
• Five control sectors with individual pyranometers • Estimated power available in each section separately and sum results • Temperatures, inverter efficiency variations, panel soiling not included in the formula (source of uncertainty)
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Operating with 10% Reserves
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AGC Test â&#x20AC;&#x201C; Aug 14, 2015 (40% range)
During a significant amount of the test period over a few days, AES PV was the only plant partcipa6ng in AGC
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Summary â&#x20AC;˘ Hardware components enabling suite of grid friendly controls are in place for many utility-scale plants â&#x20AC;˘ Work to be done on controls and communications upgrades.
â&#x20AC;˘ PV plants without energy storage are capable of providing many services to the grid but market mechanisms and new interconnection policies are needed.
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Researchers leading work presented here •
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Nelson, A., A. Hoke, S. Chakraborty, J. Chebahtah, T. Wang, and B. Zimmerly. 2015. Inverter Load Rejection Over-Voltage Testing: SolarCity CRADA Task 1a Final Report. http://www.nrel.gov/docs/fy15osti/63510.pdf Hoke, A., A. Nelson, S. Chakraborty, J. Chebahtah, T. Wang, M. McCarty. 2015. Inverter Ground Fault Overvoltage Testing. http://www.nrel.gov/docs/fy15osti/64173.pdf Suart, E, et al. Analysis of High-Penetration Levels of Photovoltaics into the Distribution Grid on Oahu, Hawaii http://www.nrel.gov/docs/fy13osti/54494.pdf Energy System Integration, High Penetration PV: How High Can We Go? http://www.nrel.gov/docs/fy16osti/65591.pdf Hoke, A., A. Nelson, B. Milller, S. Chakraborty, F. Bell, M. McCarty. 2015. Experimental Evaluation of PV Inverter Anti-Islanding with Grid Support Functions in Multi-Inverter Island Scenarios Gevorgian, V. and B. O’Neill, Advanced Grid-Friendly Controls Demonstration Project for Utility-Scale PV Power Plants Gevorgian, V. et al. Demonstration of Essential Reliability Services by a 300-MW Solar Photovoltaic Power Plant, http://www.nrel.gov/docs/fy17osti/67799.pdf
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Question / Discussion Adam.Warren@nrel.gov or 303-275-4346
Achieving a transformed energy system
Policy
Technology
People / Stakeholders
Market
Two Solar PV Examples â&#x20AC;˘ Distributed Generation in Hawaii â&#x20AC;˘ Utility-scale Solar PV in Puerto Rico
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Hawaii Energy Leadership • Hawaii Energy Goal from 2009: 70% clean energy goal by 2030, with 40% renewable and 30% efficiency Recently increased to 100% by 2045
• Hawaii Success Indicators: o
Met its 2015 renewable electricity target two years early
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Over 220 MW oil-fired generation retired
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Doubled the percentage of electricity supplied from renewable resources
For more background info: http://www.hawaiicleanenergyinitiative.org 22
HECO Energy Mix
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MW
The Growth of Solar PV in Hawaii
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Feeder PV Penetration as Percent of Daily Minimum Load .
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Feeder PV Penetration as Percent of Daily Minimum Load .
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2013 â&#x20AC;&#x201C; Feeders are reaching 120% DML 26
Interconnection Delays .
Delays lead to political pressure from industry and customers, and even to grid defection.
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The “Utility Death Spiral”
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Technology - Today’s advance invertors can avoid Over Voltage SolarCity, HECO, & NREL worked validate inverter performance with HIL testing
2016 • Research demonstrated the ability of advanced power inverters to mitigate the impacts of high penetration of solar PV on distribution grids. • HECO expedites installations of PV systems on circuits up to 250% of daytime minimum load if the PV systems are installed with advanced inverters that meet stricter requirements. 29
Market / Business Model - Hawai’i DER Policy Stream-lined Permitting and Interconnection Processes
Net Billing or Self Supply
Feed in Tariff
Net Energy Metering • Customers receive a credit at retail rate for electricity exported to the grid. • If the customer produces excess electricity, the customer pays a minimum bill (ex., $17). • Excess credits are carried forward up to a year.
• $25 min, no carry forward or
Self Supply • no export, $25 minimum
* 35% tax credit ** 24.5 % tax credit 30
HECO / SolarCity Summary Problem • In the summer of 2013, the Hawaiian Electric Company (HECO) put a moratorium on installing PV systems due to concerns about high penetration impacts on the grid.
Solution • NREL, working with SolarCity and HECO, completed research at the Energy Systems Integration Facility (ESIF) demonstrating the ability of advanced PV inverters to mitigate transient overvoltage impacts. Result • HECO cleared its interconnection queue, ending the moratorium on solar PV and raising its limit of distributed PV from 120% of minimum daytime load to 250%.
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