energy storage analysis€¦ · global energy storage market inventory, 2018. relevance/impact 4....
TRANSCRIPT
Energy Storage Analysis
Michael Penev, Chad HunterNational Renewable Energy LaboratoryApril 30, 2019
DOE Hydrogen and Fuel Cells Program 2019 Annual Merit Review and Peer Evaluation Meeting
This presentation does not contain any proprietary, confidential, or otherwise restricted information.
Project ID # SA173
NREL | 2
Overview
Timeline Barriers
Start: October, 2018
End: September, 2019*
* Annual direction determined by DOE
4.5B Stove-piped/Siloed Analytical Capability
4.5C Inconsistent Data, Assumptions and Guidelines
4.5E Unplanned Studies and Analysis
Budget Partners
FY19 Planned DOE Funding: $155K
Funds Received to Date: $155K
Collaborators• DOE, Office of Energy Efficiency and Renewable
Energy (EERE), Fuel Cell Technologies Office• DOE, EERE, Vehicle Technologies Office• Xcel Energy• Southern Company Services• Argonne National Laboratory• National Renewable Energy Laboratory
NREL | 3
Energy storage analysis assesses market relevance and competitiveness for hydrogen.
Analysis assesses hydrogen system competitive space and valuation in the landscape of energy storage technologies.
Analysis Framework
• H2FAST• Cost estimation• Competitive market
analysis• Financial analysis• Data: HDSAM,
MYRD&D, H2A, VTO targets, AMO targets
Models & Tools• H2FAST• RODeO
Studies & Analysis
• Competitive tech. assessment
• Grid support & co-products
Outputs & Deliverables
• Annual report• Inputs to working
groups • Input to HTAC
NREL: H2FAST
• H2@Scale• Additional external
reviewers
• Fuel Cell Technologies Office
• H2@Scale
AcronymsH2FAST: Hydrogen Financial Analysis Scenario ToolHDSAM: H2A Delivery Scenario Analysis ModelH2@Scale: Hydrogen at Scale
Relevance/Impact 1
NREL | 4
Energy Storage Market SegmentationRelevance/Impact 2
Duration
Service AncillaryServices
Ramping Smoothing PeakingWind
EnergyBalancing
SeasonalStorage
Seconds-Minutes
~30Minutes
~1-4Hours
~2-4Hours
Days-Weeks
Months
Current Trends: Shorter Duration
Emerging Trends: Longer Duration
Integrated Hydrogen Energy Storage + Coproduction
Current and emerging energy market trends can be met using integrated hydrogen energy storage while also co-producing hydrogen for high value uses
Market Segmentation of Energy Storage
NREL | 5
Energy Storage Needs Examples
0
10,000
20,000
30,000
40,000
50,000
60,000
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SpainFranceBritainGermanyDenmark
Win
d po
wer
(MW
)
Diurnal “Duck Curve”:- hours of storage is needed- this happens daily
Wind gaps:- days of storage is needed- this happens few times a year- long distance transmission
does not address such gaps
Relevance/Impact 3
Source: https://www.energy.ca.gov/renewables/tracking_progress/documents/resource_flexibility.pdfhttp://www.pfbach.dk/
NREL | 6
42%
37%
13%
5.6%
1%
1%
0.3%
0.09%
0 1,000 2,000 3,000
Thermal storage
Batteries
Flywheels
Compressed air w/ natural gas
Capacitors
Flow batteries
Hydrogen (power to gas)
Compressed air
Global operational capacity in 2018 (MW)
Global Energy Storage Market Inventory, 2018
Relevance/Impact 4
Source: DOE Global Energy Storage Database
Global Energy Storage Inventory: • 96% is pumped hydro serving diurnal operation• Batteries typically provide few hours of storage• Thermal storage is predominantly molten salt for concentrated solar • Fly wheels provide very short duration storage (frequency regulation)
Pumped hydro96%
NREL | 7
Landscape of Energy Storage Technologies
Source: DOE/EPRI Electricity Storage Handbook, 2015
Relevance/Impact 5
NREL | 8
Modeling Approach: Subsystem BoundariesApproach 1
Electrolyzer
8
Hydrogen Storage
Power Conditioning System
Inverter
RectifierAC DC
AC DCFuel Cell
CompressorH2 H2
H2
Electrolyzer + tank H2 storage + PEM fuel cell
Storage duration (h) 24+
Round trip efficiency 35%
Power capital ($/kW) 1,500
Storage capital ($/kWh-DC) 35
Stack life years (years) 8 – 10
Usable depth of discharge ~83%
Hydrogen systems also decouple power components (stacks, power conditioning) and energy components (hydrogen tanks), allowing more flexible design for storage duration.
Hydrogen systems also can co-produce hydrogen.
NREL | 9
Other System Configurations
ESS(Energy Storage System)
ESS+ELZR(ESS + Electrolyzer H2 Production)
ELZR(Electrolysis H2 Production)
Off-peak electricity
24/day electricity
24/day electricity
On-peak electricity
Hydrogen
Hydrogen
On-peak electricity
Three systems are evaluated in the same framework to assess integration of ESS and ELZR.
H2 storage technology can have other economic activity once storage is full.
Approach 3
NREL | 10
Simple diurnal cycle: 4 hours power generation 8 hours storage recharge 12 hours hydrogen co-production
H2 co-production would improve economics if H2 price exceeds variable operating costs.
Approach 4
Hydrogen Co-Production
-100%
0%
100%
0%10%20%30%40%50%60%70%80%90%
100%
0 24 48 72 96 120 144 168
Time (hours)
Discharging|charging
(%pow
er)
Stat
eof
char
ge(%
)
-100%
0%
100%
0%10%20%30%40%50%60%70%80%90%
100%
0 24 48 72 96 120 144 168
Time (hours)
Discharging|charging
(%pow
er) |production
Stat
eof
char
ge(%
)
NREL | 11
System Sizing Assumptions
Above system sizing allows meaningful unit capacity for grid support and hydrogen production volume. Approximately 2x installed capacity can provide sufficient hydrogen volume for large heavy duty stations.
ESS only ESS+ELZR ELZR onlyPeak power production (h/day) h/day 4 4Recharge time (h/day) h/day 8 8H2 production (h/day) h/day 12 24
Power generation (MW) MW 10 10 Power for recharging (MW) MW 11.6 11.6 11.6Power consumption (MWh/y) MWh/y 33,977 84,943 101,932 Power production (MWh/y) MWh/y 14,600 14,600 H2 production (kg/day) kg/day 2,530 5,061
ESS: Energy Storage SystemESS + ELZR: Energy Storage System + Electrolyzer Hydrogen ProductionELZR: Electrolyzer Hydrogen Production
Accomplishments 1
NREL | 12
Component Cost & Performance AssumptionsSubsystem Technology Staus & Targets, all costs in 2016$ Current status
Rectifiers Rectifier efficiency 98.4%Rectifier cost ($/kW AC) 196$ Total installation cost factor (% of equipment capital) 57%System O&M (% of capital cost) 1.0%
Electrolyzers Electrolyzer power use (kWh DC/kg) 54.3Electrolyzer cost ($/kW DC) 737$ System life (years) 20Total installation cost factor (% of equipment capital) 57%System O&M (% of capital cost) 7.8%
Compressors Power use (kWh AC/kg) 1.42Compressor cost factor A (equation form c=A*p^B; where p is power) 2290Compressor cost exponent B (equation form c=A*p^B; where p is power) 0.8225 Cost factor for inclusion of oxygen compression 50%Total installation cost factor (% of equipment capital) 187%System O&M (% of capital cost) 4.0%
Storage Terrestrial storage installed cost ($/kg) 1,168 Terrestrial storage installed cost ($/kWh LHV) 35 Terrestrial storage O&M (% of capital cost) 1.0%
Cushion gas (%) 17.1%
Fuel cells Fuel cell power production (kWh DC/kg) 20.0 Fuel cell cost ($/kW DC) 507 Total installation cost factor (% of equipment capital) 20%System O&M (% of capital cost) 6.0%
Inverters Inverter efficiency (%) 98.6%Inverter cost ($/kW) 384$ Total installation cost factor (% of equipment capital) 20%System O&M (% of capital cost) 1.0%
Feedstock Electricity cost ($/kWh) 0.033
Cost and performance inputs have been peer reviewed by all stakeholders.
Feedstock electricity cost of 3.3¢/kWh is used.
Accomplishments 2
NREL | 13
0.59 0.17
0.13 0.03
0.00
0.21 0.17
0.12 0.10
0.09 0.08
0.04 0.04 0.03
0.02 0.01 0.01 0.00 0.00 0.00 0.00
Peak electricity salesInflow of equity
Inflow of debtMonetized tax losses
Cash on hand recovery
Dividends paidOff-peak electricity
Hydrogen storagePlanned & unplanned…
Repayment of debtInterest expense
Income taxes payableElectrolyzer
Installation costFuel cellRectifier
Property insuranceSelling & administrative…
Cash on hand reserveInverter
Compressor
Operating revenue
Financing cash inflow
Operating expense
Financing cash outflow
Real levelized value breakdown of peak electricity ($/kWh)
H2FAST Model Used For Levelized Cost Analysis
-10%-8%-6%-4%-2%0%2%4%6%8%10%
0%10%20%30%40%50%60%70%80%90%
100%
0 24 48 72 96 120 144 168
Time (hours)
Discharging | charging(%
/h)
Stat
eof
char
ge(%
)
• Equipment sizing• Cost estimation• Efficiency estimation
• Energy Use• Energy Costs• Financial Assumptions
Techno-economic assessment is made based on minimal equipment sizing to achieve
benchmark cycle. H2FAST model was used to evaluate financial performance of scenarios.
https://www.nrel.gov/hydrogen/h2fast.html
Accomplishments 4
NREL | 14
Financial Assumptions
Financing InformationTotal tax rate (state, federal, local)
Capital gains taxAre tax losses monetized (tax equity application)Allowable tax loss carry-forward
General inflation rateDepreciation method
Depreciation periodLeveraged after-tax nominal discount rateDebt/equity financing
Debt typeDebt interest rate (compounded monthly)
Cash on hand (% of monthly expenses)
10.0%5 year MACRS
1.90%7 year
Yes
100%4.00%
Revolving debt1.50
15.00%27.00%
Accomplishments 3
NREL | 15
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venu
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ydro
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uctio
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venu
e fro
m h
ydro
gen
($/k
g)IRR% Sensitivity Vs. Co-Product Value
• Bubble size is proportional to project internal rate of return IRR (%)• Depending on value of electricity and hydrogen, ESS, ELZR or ESS+ELZR system yields highest IRR• ESS +ELZR can lower the price of hydrogen from ~$3 to ~$2• H2 co-production reduces the cost of produced peak power.
ELZR IRR>10%ESS+ELZR IRR>10%
ESS > 10%
Synergistic advantage: ~+8% IRR
Accomplishments 5
NREL | 16
Key Stakeholders
Reviewers• DOE Fuel Cell Technologies Office• DOE Vehicle Technologies Office• Xcel Energy• Southern Company Services, Inc.• Argonne National Laboratory• H2@Scale stakeholders
Collaboration
NREL | 17
Remaining Challenges and Barriers
Valuation of long duration storage is uncertain– Most storage projects serve diurnal needs (<24h)– Function of long-duration storage is currently served by fossil peaking plants
Limited operational data from existing energy storage projects for benchmarking
Inconsistent valuation of ancillary services by region in the US
Challenges
NREL | 18
Evaluate Means of Improving Round Trip Efficiency
Increased efficiency can be traded for capital expenses1. Increase electrolysis & fuel cell active area2. Consider solid oxide electrolysis (SOEC)3. Consider SOEC with thermal storage (store waste heat from
power generation and use for thermal needs in electrolysis)4. Consider high pressure electrolysis (reduce compression needs)5. Consider compression energy recovery with turbo expander
Round trip efficiency is more important than capital cost. Improving efficiency can be traded for increased capital cost.
Future Work 1
NREL | 19
Expand Peripheral Analysis
Incorporation of portfolio of hydrogen technologies– Reversible solid oxide fuel cell systems with thermal storage– Use of spinning equipment for power generation– Use of geologic and isostatic hydrogen storage (deep water) for larger
scales
Extend analysis into larger systems in service of H2@Scale applications
Perform select system analysis using RODeO– Detailed grid model– Perform near-term simulation of ESS economic performance– Feed into on-going work for valuation of long duration storage
Future Work 2
NREL | 20
Summary
• NREL is performing integrated energy storage and hydrogen co-production analysis– energy storage system operation can be enhanced with H2 co-production
• Simple analysis framework was used to facilitate conception of integrated systems, and evaluate impact of technology tech. targets.
• Diverse stakeholder input is received– DOE Vehicle Technology Office– DOE Fuel Cell Technology Office– Argonne National Laboratory– Xcel Energy– Southern Company Services, Inc.
• Further exploration of technology options and grid services may expand the economic viability window of hydrogen technologies
NREL | 21
BACKUP SLIDES
NREL | 22
List of Acronyms
AC Alternating Current (electricity)AMO Advanced Manufacturing OfficeDC Direct Current (electricity)DOE United States Department of EnergyEERE Energy Efficiency and Renewable EnergyESS Energy storage systemFCTO Fuel Cell Technologies OfficeH2 HydrogenH2@SCALE Hydrogen at scaleH2A Hydrogen Analysis modelH2FAST Hydrogen Financial Analysis Scenario ToolHDSAM Hydrogen Delivery Scenario Analysis ModelHTAC Hydrogen Technology Advisory CommitteekW kilowatt (unit of power)kWh kilowatt hour (unit of energy)LCOE Levelized Cost of EnergyMACRS Modified Accelerated Cost Recovery System (depreciation schedule)MW megawatt (unit of power)O2 OxygenRODeO Revenue Operation and Device Optimization ModelSOEC Solid Oxide ElectrolysisVTO Vehicle Technologies Office