1. INTEGRATED TESTING OF GRID-SCALE LITHIUM-ION BATTERY AND WIND TURBINE SYSTEMS
Davion Hill, DNV GL
Elizabeth Endler, Shell
Ben Schenkman, Sandia National Labs
Ben Gully, DNV GL
Mark Harral, Group NIRE
Dan Borneo, Sandia National Labs
Colleen Ferrall, Group NIRE
Overview and Project Objectives
Controlled tests of grid-connected, utility scale renewable energy assets
Lithium Ion energy storage system: 1 MW / 1 MWh, LMO chemistry
Wind turbine: 2 MW, GE Alstom
Over 12 weeks of testing and observation under representative operations
Frequency Regulation Test Profiles and Response
Evaluate system response to varying intensities of frequency regulation signals, using PJM signals as classified by Sandia National Labs / PNNL (Pacific Northwest)
Constant Power Cycling
Evaluation of effect of different power levels on efficiency, as well temperature rise
Battery Used for Ramp Rate Control of Wind Turbine Power Output
Utilization of the battery system to mitigate fluctuations in wind turbine output to the grid. Primarily reduce output ramp rates.
Combined Frequency Regulation and Wind Ramp Rate Control Applications
The system is programmed to respond to ramp rate control requirements as before, but is doing so in the process of frequency regulation.
Tests conducted at Group NIRE facility at Reese Technology Center
Located in Lubbock, Texas; Connected to South Plains Electric Cooperative (SPEC)
Using test protocol defined by Sandia / PNNL
Repeated 2-hour profile sampled from PJM Reg D (frequency response program specifically rewarding fast actors like storage)
Average representing typical operation and aggressive depicting extreme conditions
All frequency regulation tests were conducted with both test profiles:
PJM Frequency Regulation – Average Profile
Smaller cycles, more frequently, lower total throughput
Max power ~750 kW
165 cycles per day at 1.6%
2.64 equivalent full cycles per day
Average AC efficiency: 72.60
Average DC efficiency: 83.60
PJM Reg D Precision score: 99.74
PJM Frequency Regulation – Aggressive Profile
Larger cycles, greater total throughput, higher power = higher efficiency
Uses max battery power of 1,000 kW
131 cycles per day at 2.6%
3.40 equivalent cycles per day
Average AC efficiency: 79.47
Average DC efficiency: 86.37
PJM Reg D Precision Score: 99.64
Constant Power Cycling for Efficiency Assessment
Higher power produced higher efficiency
Less auxiliary power draw from shorter operation time
Higher electrochemical efficiency
AC losses (including inverter and transformer) 6.32% to 7.28% higher
Round Trip Efficiencies (RTE) as tested, expressed as percentage:
Battery Used for Ramp Rate Control of Wind Turbine Power Output
Objective is to minimize fluctuation in output power to grid during any given 1-minute interval
Capability is limited to battery’s power of 1 MW
Power outputs of each device shown in top graph
Bottom graph shows change in power output in each 1-minute interval
From wind turbine and from wind turbine including battery assistance
Requirements for charge and discharge (occurrence, power level) were very balanced
Battery successfully demonstrated ability to reduce power output fluctuation by its maximum power level
Demonstrated as being dominantly a power application
Single extreme case of max power 5-minute duration caused Delta State of Charge (DSOC) of 25%
Majority of support operations are low power
Combined Frequency Regulation and Wind Turbine Ramp Rate Control Applications
Using same metric of power output fluctuation within each minute
Controls prioritizing turbine ramp rate control, when needed, over frequency regulation
Single instance of battery not providing full power for ramp control
During aggressive frequency response
Single instance of frequency response requiring same power as wind and both signals cancelling
Highest DSOC experienced was 25%
1,170 kW for just under 5 minutes
Maximum temperature of 27°C, temperature gradient of 8°C across pack.
Given low rate of occurrence, wind turbine ramp support activities proved to have minimal effect on PJM Reg D Precision Score
Conclusions
Demonstrated % DC-DC RTE
Higher powers providing higher efficiency
AC RTE % lower
Significant impact of HVAC and auxiliary loads which can be up to 50 kW
Frequency regulation showed 72-86% RTE – again with higher power yielding greater RTE
2.64 (average) and 3.40 (aggressive) equivalent full cycle throughput per day
Combined application testing proved to have minimal or zero effect on PJM Reg D precision score compared to frequency regulation testing alone
Frequency regulation and wind ramp support proved to equally be ‘power’ applications
Primary consideration in sizing should be peak power requirements (not energy)
Energy should be considered under pretense of aggressive downsizing
Contact
Ben Gully, DNV GL:
Davion Hill, DNV GL:
Elizabeth Endler, Shell International Exploration & Production:
1 MW / 1 MWh Li-Ion (LMO) Battery, Younicos
2 MW GE-Alstom ECO-86 wind turbine
Precision Performance Score
Stacked Application Test Number
Average Frequency Regulation
Aggressive Frequency Regulation 1
99.23
99.26 2
99.94
99.66
Baseline (no wind)
99.74
99.64
Thank you
The DOE Office of Electricity and Dr. Imre Gyuk, Program Manager of the Electrical Energy Storage Program
GroupNIRE
Sandia National Laboratories
Cycle 1
Cycle 2
Cycle 3
Average
AC-DC
Power (kW)
DC RTE
AC RTE
ΔRTE
250
81.16
73.67
82.08
75.42
83.25
75.55
82.16
74.88
7.28
500
91.03
83.57
88.64
79.38 --
89.84
81.47
8.37
1000
91.65
85.33
6.32