recent technology developments for utility-scale and

SPARK Introduction | February, 2016 | 1

Recent Technology Developments for Utility-Scale and Distributed Battery Energy Storage Systems

Dan M. Ionel, Ph.D., FIEEEProfessor and L. Stanley Pigman Chair in PowerPEIK and SPARK Director, University of Kentucky

November 5, 2019Brasov, Romania

Electric Battery Energy Storage | November 2019 | 2SPARKLaboratory

Outline

• Introduction

•Utility scale batteries• Kentucky (KY) research facility 10MW PV and 1MW/2MWh BESS• PV and load variation• EPRI, utilities and academic projects• Example of new system configuration study

•Distributed residential energy storage• Net zero energy (NZE) homes and the “duck curve”• Co-simulation of buildings and electric distribution power systems• DOE, OEM and utility example projects: HyESS, HEMS and VPP• One of US’ largest rural smart grid demonstrators

•Conclusion.


University of Kentucky (UK), PEIK and SPARK• Land grant and flagship university in

the Commonwealth of Kentucky, established in 1865

• Total students approx. 30,000• Many learned electric machines and

drives from the Nasar and Boldea books

• The Power and Energy Institute of Kentucky (PEIK) was created in 2010 at UK with DOE support

• Multidisciplinary with 16 affiliated CoEUK faculty and many graduate students

• Existent endowments include TVA and Kentucky Utilities

• New L. Stanley Pigman Chair endowment established in 2014/2015

• The SPARK Lab, one of the PEIK affiliated labs, was established in 2015/2016.


Teaching, Research, Fastest Solar Car, and Outreach


Solar PV Plus Energy Storage 101 – Power and Energy

Source: March 2019, US Department of Energy (DOE),based on NREL study.


High Power and High Energy Batteries in US

• The far majority of the batteries are of the Li-ion type• Early implementations – high power batteries in PJM (Nord East) for frequency

regulation and grid stability• Recent trends – high energy, especially in CAISO (California) to support

renewables implementation and load shift.


Energy Storage Deployment in the US


Battery Energy Storage System (BESS) 101 – Cost

Source: March 2019, US Department of Energy (DOE), based on NREL study.For $ order of magnitude clarification see next slide.


PV and BESS 101 – Cost

Source: March 2019, US Department of Energy (DOE), based on NREL study.


LG&E-KU EW Brown Power Plant and PV Installation


Power Variation: PV and Load


Battery Energy Storage System (BESS) at EW Brown Site


Developments on the LG&E-KU EW Brown Site• LG&E and KU is the largest utility in

Kentucky• The Energy Storage Research and

Demonstration site is a joint project with EPRI and a consortium of other utilities

• Co-located with 10 MW Universal Solar facility

• Multiple testing bays for evaluation of storage and grid integration technologies

• Space available for future developments, e.g. microgrids, advanced power electronics, solid state transformers, etc.


A 1MW/2MWh Battery Energy Storage System…

… can fully supply a house in Hawaii for 4 months from a single charge

… can simultaneously power 230 electric heaters (50gal)

… would take 15 days to completely charge from a 30kW solar PV (RGAN UK)

… may be used to increase the capacity factor of a 1MW PV farm by as much as 15%


KY LG&E-KU EW Brown BESS Research and Demo Site

• Currently operational: 10MW PV, 1MW 2MWh Li-ion battery, 1MW controllable load bank, SCADA system; nearby 138kV transmission line and large GW-level power plant

• Testing bays (2x) with concrete pier design to support containerized storage solutions • Up to two 10’ x 53’ containers per testing bay

• Testing bay (1x) with large concrete pad foundation (65’ x 20’)• Underground trench system for cables.


Inverter for Battery

• 1,000 kW continuous• 1,000 kVAR continuous• 96% Efficiency• 740-1150 VDC input• 480 V Delta 3 ph output• 4 Quadrant operation• Full Lead/Lag capability up to

1000 kVA• 11 control functions.


Energy Storage System – Li-ion Battery Unit

• LG Chem 1 MW, 2 MWh• 17 modules per rack (340

total)• 10 racks per container (20

total)• 2 containers• Operates at 900-1000 VDC.


PSCAD Model for the EW Brown System • Battery energy storage system (BESS) rated for 1MW, 2MWh• PV system consists of 10 arrays and associated inverters connected

in parallel with each rated for 1MW• Synchronous generator connected for simulation on the 13.2kV bus• Variable load bank to absorb both active and reactive power at

specified voltage.


PSCAD Model of the PV System

• A PV array includes up of 19 modules connected in series and 236 module strings in parallel

• Each module has an open circuit voltage of 46.75V and short circuit current of 9.02A, according to manufacturers’ data

• Inverter – power electronics circuit DC/AC.

Power circuit diagram in the PSCAD software for a module comprising a PV array, a 2-level inverter, filter, and a transformer connected to thepower grid.


Frequency Regulation and Stability Studies• Example PV system connected to a modified IEEE – 14 bus system such that it

supplies part of the power at Bus no. 2; synchronous generator 100MW and PV plant 10MW

• Sudden irradiance variation and optimal controls• PSCAD time transient simulations.

“Modeling of a Multi-Megawatt Grid Connected PV System with Integrated Batteries”, Vandana Rallabandi, O. Akeyo, D. M. Ionel, ICRERA 2016, best paper award.


EPRI and the Energy Integration Council (ESIC)• The Electric Power Research Institute (EPRI) is an independent nonprofit

organization that conducts research, development, and demonstration projects in collaboration with the electricity sector; EPRI’s annual expenditure is higher than $400 million

• The Energy Storage Integration Council (ESIC) established in 2013 as an open technical collaboration between utilities, OEMs, National Labs, and industry experts

• ESIC Energy Storage Test Manual, Dec. 2017.


EPRI/ESIC ES Test Manual – Example Recommendations

Example schematic representation for BESS real power output during performance tests.

• One complete charge and discharge cycle per day in order to ensure stabilization and thermal equilibrium

• The min. time delay between consecutive charge and discharge cycles should be 10 minutes in order to ensure BESS open circuit voltage stability

• Battery enclosure temperature should be maintained at 23oC or manufacturer’s recommended temperature

• All instrumentation should have a min. sampling rate of 128 samples per cycle

• Measurements should be synchronized

• BESS must operate at the US utility distribution voltage and frequency.


Utility Scale BESS Characterization

• Pulse charging and discharging atconstant power; changes of voltageand current

• Reactive power is maintained at zerothroughout the process

• Transients are analyzed in order todetermine the battery equivalentcircuit parameters.


Equivalent Circuit Parameters

• A large BESS contains hundreds or thousands of elements connected in series or parallel

• Traditional methods do not consider the capacitive elements.


Research on PV Systems with Battery Storage

Proposed system:• Battery charges during period of excess irradiance

leading to a 15% increase in the “clear day” capacity factor

• The bidirectional DC/DC converter is used for• charge control and MPPT simultaneously• charge and discharge the BESS in order to

regulate the grid frequency• The DC/AC inverter may be used for reactive

power support when there is no solar irradiance.

(a) Conventional (b) Experimental (c) Proposed


Power Electronics, Controls and Power Smoothing


Battery Sizing for Fully Dispatchable Solar PV

• Charge the battery when the instantaneous ac powerfrom the PV system, Pac, exceeds the set value of thedispatchable power to the grid, Pd

• Discharge the battery at other times• On an example clear day

• A 10MW PV system with a 6.5MW/36MWh battery• Will deliver 3.6MW constant power for 24 hours.


Net Zero Energy (NZE) Home Technologies: PV, BESS, VPP• As of 2020 all new

constructions in California have to be NZE large PV penetration

• New innovative technologies for PV and energy storage are required large penetration of distributed energy storage expected longer terms

• New HEMS and VPP dispatchable homes and communities

• Examples from DOE, NSF, OEM and utility sponsored projects at UK PEIK and SPARK.


Neighborhood with NZE Homes with Energy Storage (ESS)

• Modified IEEE 13-feeder test case with 60 (sixty) NZE homes connected to node 634

• Co-simulation with Energy+ and OpenDSS

• Power flow profile at node 634• Summer day (top)• Winter day (bottom)

• The “duck curve” is alleviated for both example days.


Example of Hybrid PV ESS for NZE Home• PV and BES are connected to the DC bus• EWH is connected to the

• DC bus, to absorb excess PV generation• AC mains, to ensure consumer comfort

• Reduces to approx. half the required capacity for the battery (BESS).


Virtual Power Plant (VPP) for “Dispatchable” Homes

Summer WinterW

ithou

t VPP

With

VPP


Virtual Power Plant (VPP) for Large Communities

Inspired by the Sandia VPP report: https://prod-ng.sandia.gov/techlib-noauth/access-control.cgi/2017/1710177.pdf

https://prod-ng.sandia.gov/techlib-noauth/access-control.cgi/2017/1710177.pdf


Glasgow, KY, One of US’ Largest Rural Smart Grid Demonstrators

• Left: the community served by the Glasgow Electric Plant Board (GEPB) and the Smart Energy Technologies (SET) project

• Total 5,000+ homes• Specially equipped, 300 homes• Home energy management (HEM) with smart thermometer, EWH and BESS

• House types (schematic representation on the right figure)• Conventional (Conv) without any HEM• HEM realized by HVAC, EWH, BESS (HEB)• HEB with improved insulation (HEB_I)• HEB with PV (HEB_PV)• HEB with PV and improved insulation (HEB_PV_I).

BES

EWH

Smartthermostat


Co-simulation of Buildings and Power Distribution

• The new INSPIRE+D co-simulation framework developed by the SPARK Lab is able to model

• Individual houses and the electric power distribution power system• Instantaneous residential power demand• Power flow of the distribution system• Control signals for optimization

• EnergyPlus (LLNL) and OpenDSS (EPRI) used for computational engines• HPC implementation for thousands of homes.


Simulations for Different Home Types (CA Example)

RefPV PVBS RefEV

PVEV BSEV PVBSEV

• Net power flow of different house types for the entire year• Swimming pool pump operates from 9:00 to 15:00 everyday• BESS charges around 13:00 and discharges around 16:00 everyday• EV discharges from 00:00 to around 3:00 everyday.


Home and Community Co-simulation Framework

• BEopt: building house energy model data input• EnergyPlus: generates instantaneous power demand, and other residential

energy data• OpenDSS: solves the power flow• Distribution management system (DMS): optimizes the power flow (under

development).


HVAC and EWH Controls for Example Home• Winter day • EnergyPlus results for a typical family

home with 3 bedrooms and 1.5 bathrooms

• The effect of room temperature set point controls on HVAC (left graphs)

• EWH conventional and with DR and various technologies, i.e. HVAC & battery, and HAVC & battery & PV (bottom).


Technology Penetration Studies wo HEM-VPP – Winter

• Simulation results• Baseline

• Morning and evening peak• Solar heat contributes to the demand

reduction in the midday

• Case 2• Similar trend as baseline• Energy saving due to higher insulation

from 25% of the houses

• Case 3• 25% house have improved insulation• 50% houses have PV

• Case 4• 40% houses have improved insulation• 40% houses have PV

• Case 5• 50% houses have improved insulation• 50% houses have PV.


Technology Penetration Studies with HEM-VPP – Winter


• Morning and evening peak• Solar heat contributes to the

demand reduction in the midday

• Case 2• 50% houses have HEM• No PV penetration

• Case 3• 50% houses have HEM• 50% houses have PV• “Duck curve” still exists

• Case 4• 80% houses have HEM• 40% houses have PV

• Case 5• 100% houses have HEM• 50% houses have PV.


Technology Penetration Studies wo HEM-VPP – Summer


• Evening peak• Demand ramps up from morning

• Case 2• Similar trend as baseline• Energy saving due to higher insulation

from 25% of the houses

• Case 3• 25% house have improved insulation• 50% houses have PV

• Case 4• 40% houses have improved insulation• 40% houses have PV

• Case 5• 50% houses have improved insulation• 50% houses have PV.


Technology Penetration Studies with HEM-VPP – Summer


• Evening peak• Demand ramps up from morning

• Case 2• 50% houses have HEM• No PV penetration

• Case 3• 50% houses have HEM• 50% houses have PV• “Duck curve” still exists

• Case 4• 80% houses have HEM• 40% houses have PV

• Case 5• 100% houses have HEM• 50% houses have PV.


Conclusions

•What a difference a few years can make…•New utility-scale trends

•Falling prices for PV•Exponential growth deployment for Li-Ion batteries•New standards to test multi-MW/MWh batteries•Very large solar PV farms with integrated batteries able to

deliver rated power for 4-6 hours•New residential distributed PV and BESS

•New NZE regulations•New utility rate/pricing schemes •New combined systems: ESS and HEMS •Large community level VPP

•How long until “full” industrial and utility application maturity?


Special Thanks and Further Readings

• Special thanks to my collaborators and students who contributed to the work described in this presentation

• Example recent SPARK papers http://sparklab.engr.uky.edu• Jones, E. S., Gong, H., and Ionel, D. M., “Optimal Combinations of Utility Level Renewable Generators for a Net Zero Energy Microgrid

Considering Different Utility Charge Rate”, Proceedings, IEEE ICRERA 2019, Brasov, Romania, 4p (Nov 2019)• Alden, R. E., Han, P., and Ionel, D. M., “Smart Plug and Circuit Breaker Technologies for Residential Buildings in the US”, Proceedings,

IEEE ICRERA 2019, Brasov, Romania, 4p (Nov 2019)• Gong, H., Rallabandi, V., McIntyre M. L., and Ionel, D. M., “On the Optimal Energy Controls for Large Scale Residential Communities

including Smart Homes”, Proceedings, IEEE ECCE 2019, Baltimore, MD, 5p (Oct 2019)• Akeyo, O., Rallabandi, V., Jewell, N., and Ionel, D. M., “Measurement and Estimation of the Equivalent Circuit Parameters for Multi-

MW Battery Systems”, Proceedings, IEEE ECCE 2019, Baltimore, MD, 6p (Oct 2019)• Zhang, Y., Akeyo, O., He, J., and Ionel, D. M., “On the Control of a Solid-state Transformer for Multi-MW Utility-Scale PV-Battery

Systems”, Proceedings, IEEE ECCE 2019, Baltimore, MD, 6p (Oct 2019)• Akeyo, O. M., Rallabandi, V., Jewell, N., and Ionel, D. M., "Modeling and Simulation of a Utility-Scale Battery Energy Storage System",

Proceedings, IEEE PESGM 2019, Atlanta, GA, 5p (Aug 2019)• Gong, H., Rallabandi, V., and Ionel, D. M., "Load Variation Reduction by Aggregation in a Community of Rooftop PV Residences",

Proceedings, IEEE PESGM 2019, Atlanta, GA, 4p (Aug 2019)• Zhang, Y., He, J., and Ionel, D. M., “Modeling and Control of a Multiport Converter based EV Charging Station with PV and Battery”,

Proceedings, IEEE ITEC 2019, Novi, MI, 5p (Jun 2019)• Akeyo, O. M., Rallabandi, V., Jewell, N., and Ionel, D. M., "Battery Testing According to the New EPRI Guide and Applications to

Distribution Systems", DistribuTECH 2019, New Orleans, LA (Feb 2019) • Gong, H., Akeyo, O. M., Rallabandi, V., Colliver, D., and Ionel, D. M., "On the Control of Distribution Power System for Low-income

Low-cost Net Zero Energy Communities", DistribuTECH 2019, New Orleans, LA (Feb 2019) • Alawhali, N., Akeyo, O. M., Rallabandi, V., and Ionel, D. M., "Community-based Hybrid Wind and Solar PV Farm", DistribuTECH 2019,

New Orleans, LA (Feb 2019)• Rallabandi, V., Akeyo, O. M., Jewell, N., and Ionel, D. M., “Incorporating Battery Energy Storage Systems into Multi-MW Grid

Connected PV Systems”, IEEE Transactions on Industry Applications, Vol. 55, No. 1, pp. 638-647, doi: 10.1109/TIA.2018.2864696 (2019).

http://sparklab.engr.uky.edu/


Thank you!

https://www.engr.uky.edu/powerhttp://sparklab.engr.uky.edu

https://www.engr.uky.edu/power

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