03-simmons-water and energy...

Energy Storage:Energy Storage:The Enabler of the Use of Solar and The Enabler of the Use of Solar and

Wind EnergyWind Energy

Joseph H. Simmons and Ardeth M. Barnhart Co-Directors

AzRISE – The Arizona Research Institute for Solar EnergyUniversity of Arizona

http://www.azrise.org

The University of ArizonaIn alliance with

University of Phoenix

Overview

? Statement of the problemqWind EnergyqSolar Energy

? Useful Storage TechnologiesqBatteriesqCompressed Air Energy Storage

? Opportunities in ArizonaqGeology



Hourly Wind Production is not Reproducible

Hours à



Rated Power2,640 Watts peak

Solar has short-term intermittency due to weather

Data from TEP Test Yard – Alexander Cronin



Sudden Drop in Wind Energy

February 2008 ‘Texas Event’: 1,200 MW drop in 3 hours



Day-to-day Production Variation(Data from TEP Test Yard – Alexander Cronin)



00

500500

1,0001,000

1,5001,500

2,0002,000

2,5002,500

00

22

44

66

88

1010

1212

11 22 33 44 55 66 77 88 99 1010 1111 1212 1313 1414 1515 1616 1717 1818 1919 2020 2121 2222 2323 2424

Sys

tem

Pea

k, M

WS

yste

m P

eak,

MW

Ren

ewab

le R

esou

rce,

MW

Ren

ewab

le R

esou

rce,

MW

Renewable Resource Capacity ProfileRenewable Resource Capacity ProfileTypical Summer Load Typical Summer Load Profile versus Profile versus Renewable AvailabilityRenewable Availability

Summer Load ProfileSummer Load Profile

AZ WindAZ Wind

NM WindNM Wind

Solar PVSolar PV

Solar 1Solar 1--AxisAxis

Solar 2Solar 2--AxisAxis

Solar CSPSolar CSP

Solar CSP 6 HourSolar CSP 6 Hour

8 HoursHours

System PeakEnergy Generation does not match load

Provided by Mike Sheehan - TEP



Seasonal Mismatch Between Demand and Production

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1 2 3 4 5 6 7 8 9 10 11 12

Meg

aWat

t -ho

urs

Months of the Year

PV Production 5.2 GW

TEP Consumption

Solar PV

Energy Storage – A Critical Componentin the Development of a Solar America

? Energy storage is critical:q Supply side: Intermittent renewable energy sources – Solar and Windq Demand side: Large variations in demand (peak-load shaving)q Short term weather intermittencyq Day-to-day variations and sudden drop in powerq Load mismatchq Seasonal Mismatch

? Energy storage must be:q Inexpensive, Efficient, Rapid reaction to loss of powerq Available in sufficient capacityq Seasonal arbitrage, load shifting, regulation q National Energy Reserve

Energy Storage

BatteriesSupercapacitorsFlywheelsHydrogenFuel cells

Compressed air in vesselsUnderground compressed airPumped hydroelectricThermal storageSuperconducting magnetic energy

Full power duration of storage technologiesDuration Biomass Hydrogen CAES Thermal Hydroelec Flow cell batteries Supercap

4 mos + + +3 weeks + + +3 days + + + + +6 hours + + + + + + +2 hours + + + + + + +40 min + + + + + +10 min + + + + +20 sec + + +1 second +

Sam Jaffe – ESA 09 (Energy Insights)Summary of Energy Storage approaches:

Ideal Combination of Storage Technologies

? Fast Response (expensive):q Supercapacitors (milliseconds)qBatteries (hundreds of milliseconds)

? Longer time response with higher capacity (lower cost):qCompressed air energy storage q Pumped hydroelectricq Thermal storage technologies

? Very long time response (lowest cost):qDemand response or load control

Compressed Air Energy Storage

? Generation/storage systems integration? Efficiency w/o heat recovery: 65%, with: 85%? Isothermal vs adiabatic pumping? Turbine vs vessel size? Costs and economics

? Air Storage:? Subsurface imaging to greater than 2,000 feet? Solution mined salt, drilled alluvium? Depleted natural gas wells, abandoned mines? Above-ground tanks, underwater tanks

Compressed air storage cavern/above ground vessel

Heat exchanger Gas heater

Gen 1 Gen 2

Gen 3 Gen 4

Bus

Solar Power GeneratorPV, Thermal,

ConcentratorsInverter

Step-upTrans-

former

Step-upTrans-former

WindGenerator

Step-downTrans-former

ACCompressor

DCCompressor

Electric transmission grid

Excess generation

Hot air

Hot air Hot air

Energy Storage – A Critical Componentin the Development of a Solar America

? Compressed Air Energy Storage (CAES)q Above ground (vessels)

Storage for a few hoursAutomotive applications

? Underground Compressed Air Storage (1,100 psi, 75 atmo.)q Needs salt deposits (primary)q High efficiency and low price (65-90%)q Needs additional fuel for operating the

turbine (natural gas or biofuels)q UA research –

? Adiabatic pump with heat recovery using molten salt storage? Hydrogen heating for additional fuel? Salt deposits and alluvium for underground storage? Mining sites and mine tailing banks? Demonstration site (Riverpoint Solar Research Park)

Load Shifting Function

Load Shifting Function – CAES Capacity

(500.000)

0.000

500.000

1,000.000

1,500.000

2,000.000

2,500.000

3,000.000

3,500.000

4,000.000

0 5 10 15 20 25 30

Ene

rgy

in M

Wh



Addition of CAES to Meet Seasonal Differences

-600,000

-400,000

-200,000

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1 2 3 4 5 6 7 8 9 10 11 12Meg

aWat

t -ho

urs

Months of the Year

PV Production 5.2 GW

CAES Produced Electricity

TEP Consumption

CAES Stored Energy

Underground Compressed Air Storage in Salt Caverns

? Holbrook salt basin covers 3,500 square miles and is 300 feet thick.

? Holbrook basin has the capacity to store 30TW of electrical production –more that the US total energy demand (3.3 TW) or 30 times the electrical demand (1 TW).

? Many salt basins are distributed throughout Arizona

? Luke, Picacho and Holbrook are currently used to store natural gas or propane

Other Technologies

? Liquid Air? Thermal systems? Pumped hydroelectric? Flywheels? Supercapacitors? Other batteries:qDeep discharge, graphite enhanced lead acid

batteriesqVanadium redox flow batteries

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