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122 West

Short v. Long Term Energy Storage Analysis

Susan M. SchoenungLongitude 122 West, Inc.

William V. HassenzahlAdvanced Energy Analysis

DOE Energy Storage Systems Program ReviewNovember 19, 2002

Work Sponsored by the DOE ESS ProgramHome

Agenda

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122 West Objectives

• Previous work compared energy storage technologies: power ratings, storage duration, response time, capital cost, commercial maturity.

• This work extends energy storage characterization to include life cycle cost analysis. Elements addressed: efficiency, O&M, parasitic losses and replacement costs.

• The overall goal is to provide quantitative comparison of alternative energy storage technologies in applications with varying discharge time.

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122 West Contract Tasks

1) Technology update: costs and performance

2) Life cycle cost analysis for varying sizes ofenergy storage

3) Comparative analysis of rechargeablebatteries and fuel cells

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122 West Application Categories and Specifications

Applicat ionCategory

Dischargepower range

Discharget imerange

St ored energyrange

Representat iveApplicat ions

Bulk energyst orage

10 - 1000 M W 1 - 8 hr s 10 - 8000 MWh Load leveling,spinning r eserve

Distr ibutedgenerat ion

100 - 2000 k W 0.5 - 4 hr s 50 - 8000 k Wh(0.05 - 8 MWh)

Peak shaving,t ransmissiondeferral

Powerqualit y

100 - 2000 k W 1 - 30 s ec 0.1 - 60 M J(0.028-16 .67kWh)

End-use powerqualit y andreliability

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122 West Energy Storage Systems

PCSEnergyStorage

Unit~

3Ø AC

Source/Load

Load Management

PCS

Load

EnergyStorage

~

Source

3Ø AC

Fuel Cell HydrogenStorage

~ 3Ø AC

Source / Load

e-

e-

H2

H2

Electrolyzerand

Compressor

Power Quality

Hydrogen

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122 West Approach to Life Cycle Cost Analysis

Levelized annual cost ($/kw-yr)= Cost of capital (carrying charge on initial purchase)+ cost of fixed O&M + cost of variable O&M + annualized replacement costs+ consumables (fuel and electricity)

Convert to Revenue Requirement (¢/kWh) bydividing by hours of operation per year

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122 West Life Cycle Cost Analysis Data

• Capital cost: power, energy, Balance-of-Plant• Round trip efficiency, AC-AC• Operating costs: fixed O&M, variable O&M,

electricity, fuel• Replacement frequency and costs• Parasitic losses (e.g., cooling)• Economic assumptions: cost of electricity, fuel,

interest and inflation rates

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122 West Economic and Operating Assumptions

Parameter ValueGeneral inf lat ion rat e 2.5%Discount r at e 8.5%Levelizat ion period 20 yearsCarrying charge rat e 12%Fuel cost, n atu ral gas $5.00 /MBTUFuel cost, escalat ion rat e 0%Electr icit y cost ( off- peak) 5 ¢/k WhElectr icit y cost , escalat ion rat e 0%O&M cost escalat ion rat e 0%Days operati on/ year 250

Operating assumptions: • discharge/charge time: assume equal, except for hydrogen systems• discharges per day: assume once per day• operations per year: assume 250 days per year

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122 West Bulk Energy Storage Technologies

• Lead-acid (flooded) and VRLA batteries• Regenesys® system• High temperature sodium/sulfur batteries• Zn/Br batteries• Vanadium-redox batteries• Ni/Cd batteries• CAES• Pumped hydro and pumped hydro with variable

speed drive

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122 West

Levelized Annual cost of bulk storage options

0

500

1000

1500

0 1 2 3 4 5 6 7 8Hours of storage available for discharge

Lead-acid battery (flooded cell)Lead-acid battery (VRLA)Na/SZn/BrRegenesysNi/CdCAESPumped HydroPumped Hydro with Variable Speed Driv

Ann

ual C

ost,

$/kW

-yr

Bulk Energy Storage - Preliminary Results

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122 West Bulk Energy Storage - Preliminary Results

Revenue Requirement for Bulk Energy Storage Technologies

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8

Discharge time, hrs per day

Lead-acid battery (flooded cell)

Lead-acid battery (VRLA)

Na/S

Zn/Br

Regenesys

Ni/Cd

CAES

Pumped Hydro

Pumped Hydro with VariableSpeed DriveR

even

ue R

equi

rem

ent,

cent

s/kW

h

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122 West Bulk Energy Storage - Preliminary Results

Components of Annual Cost for Bulk Storage Technologies (8 hr discharge)

0

200

400

600

800

1000

1200

1400

1600

1800

Lead-acidbattery(flooded

cell)

Lead-acidbattery(VRLA)

Na/S Zn/Br Regenesys Ni/Cd CAES PumpedHydro

PumpedHydro with

VariableSpeed Drive

Replacement CostO&M CostElectricity CostFuel CostCarrying Charges

Ann

ual C

ost,

$/kW

-yr

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122 West Distributed Generation Technologies

• Lead-acid (flooded) and VRLA batteries• High temperature sodium/sulfur batteries• Zn/Br batteries• Vanadium-redox batteries• Ni/Cd batteries• Li-Ion batteries• High-speed flywheels• CAES with surface storage• Hydrogen – fuel cells and engines

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122 West Distributed Generation - Preliminary Results

Levelized Annual Costs for Distributed Generation Storage Technologies

0

100

200

300

400

500

600

700

800

900

0 1 2 3 4

Discharge time, hrs

Lead-acid battery (flooded cell)

Lead-acid battery (VRLA)

Na/S

Zn/Br

V-redox

Li-ion

Ni/Cd

High speed flywheel

CAES-surface

Hydrogen fuel cell

Hydrogen engine

Ann

ual C

ost,

$/kW

-yr

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122 West Distributed Generation - Preliminary Results

Revenue Requirement for DG Technologies

0

20

40

60

80

100

120

140

160

180

200

0 0.5 1 1.5 2 2.5 3 3.5 4

Discharge time, hrs per day

Lead-acid battery (flooded cell)Lead-acid battery (VRLA)Na/SZn/BrV-redoxLi-ionNi/CdHigh speed flywheelCAES-surfaceHydrogen fuel cellHydrogen engine

Rev

enue

Req

uire

men

t, ce

nts/

kWh

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122 West Distributed Generation - Preliminary Results

Components of Annual Cost for DG Technologies (1 hr discharge)

0

50

100

150

200

250

300

Lead-acidbattery(flooded

cell)

Lead-acidbattery(VRLA)

Na/S Zn/Br V-redox Li-ion Ni/Cd Highspeed

flywheel

CAES-surface

Hydrogenfuel cell

Hydrogenengine

Replacement CostO&M CostElectricity CostFuel CostCarrying Charges

Ann

ual C

ost,

$/kW

-yr

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122 West Distributed Generation - Preliminary Results

Cost Components for DG Technologies (4 hr systems)

0

100

200

300

400

500

600

700

800

900

Lead-acidbattery(flooded

cell)

Lead-acidbattery(VRLA)

Na/S Zn/Br V-redox Li-ion Ni/Cd High speedflywheel

CAES-surface

Hydrogenfuel cell

Hydrogenengine

Replacement Cost

O&M Cost

Electricity CostFuel Cost

Carrying Charges

Ann

ual C

ost,

$/kW

-yr

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122 West Power Quality Technologies

• Lead-acid and advanced batteries

• Micro-SMES

• High-speed flywheels

• Low-speed flywheels

• Supercapacitors

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122 West Power Quality - Preliminary ResultsLevelized Annual Cost for Power Quality Technologies

0

20

40

60

80

100

120

0 5 10 15 20 25 30

Discharge time, seconds

Lead-acid battery

Advanced battery (projected)Micro-SMES

High speed flywheel (1)

High speed flywheel (2)

Low speed flywheelSupercapacitors

Ann

ual C

ost,

$/kW

-yr

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122 West Power Quality - Preliminary ResultsComponents of Annual Cost for Power Quality Technologies

(20 sec discharge)

0

10

20

30

40

50

60

70

80

90

Lead-acidbattery

Advancedbattery

(projected)

Micro-SMES High speedflywheel (1)

High speedflywheel (2)

Low speedflywheel

Supercapacitors

Replacement costO&M CostElectricity CostFuel CostCarrying Charges

Ann

ual C

ost,

$/kW

-yr

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122 West

Components of Annual Cost for Power Quality Systems (1 sec discharge)

0

10

20

30

40

50

60

70

80

Lead-acid battery Advanced battery(projected)

Micro-SMES High speedflywheel (1)

High speedflywheel (2)

Low speedflywheel

Supercapacitors

Replacement costO&M CostElectricity CostFuel CostCarrying Charges

Ann

ual C

ost,

$/kW

-yr

Power Quality - Preliminary Results

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122 West Issues

•Data difficult to get, and to distinguish current costs from projections.

• For some technologies, difficult to separate power and energy components.

•Difficult to be generic, e.g., batteries, flywheels

• Algorithm complications: replacements, parasitics

• Balance-of-Plant: buildings included in bulk, not DG

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122 West Preliminary Conclusions

• Bulk storage in geologic formations or tanks is least expensive for long-duration applications.

• Regenesys and Na/S batteries look attractive for bulk storage, but all advanced battery types are immature and cost conclusions are preliminary.

• Revenue requirements are high for most technologies -suitable for select peak shaving/arbitrage applications only.

• Replacement frequency and cost are significant cost factors, and are highly uncertain.

• Hydrogen has a role to play in clean DG situations.• Power quality systems need accurate time duration

specifications to optimize technology selection.

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122 West Follow-on Analysis

•Sensitivity of results to cost assumptions and replacement frequency

•Add UPS category: 30 sec to 15 minutes

•Consider taxes and other economic factors

•Compare annual costs / revenue requirements with markets

•Revisit costs for surface CAES

•Consider additional technologiesTop

Agenda