Energy Storage Systems Prof. G. Bothun Dept. of Physics University of Oregon

Scalable Energy Storage: Evaluations of Choices GRID CAPACITY GRID RELIABILITY Power Plant X RENEW STORAGE

Key Points: Defining the 10%/1 Hour Goal Conceptual Overview of Energy Storage Evaluating Rubrics for Competing Technologies Specific Examples of Current Technologies Hydrogen as a Proxy for Transmission lines

The 10% / 1 Hour Objective 2005: 3600 Billion KWHs 50 Giga Watts for 1 Hour

A More Personal Scale Individual Americans use 1.5 KWH of electricity every hourIndividual Americans use 1.5 KWH of electricity every hour 10% / 1 Hour objective equates to the individual requiring 150 Watt Hours of storage for one hour10% / 1 Hour objective equates to the individual requiring 150 Watt Hours of storage for one hour A 2-4 KG Battery Pack or 10 grams of gasoline! Our Consumption scale is Large

Needs For Energy Storage Smooth over fluctuations in regional electricity demand due to varying peak Safety net for intermittent energy supplies such as wind, solar, seasonal variations in hydro or biomass Means of recovering waste energy Regulatory necessity for more reliable electricity delivery

Future Baseline Supply Plan is LNG

Seize the Opportunity? Nearly 2/3 of the natural gas used in gas fired power plant drive’s the compressor. Nearly 2/3 of the natural gas used in gas fired power plant drive’s the compressor. Use Wind Energy to charge a compressed air storage systems and store it underground Feed it to the compressor

Managing Peak Load with Storage 80% Load for 50 Days  MWH of Storage  200% Load for 9 Days 1000 MW

But Peak Demand Is Increasing

Peak Demand Climate Driven

Choices and Estimated Costs Pumped Hydro Li-Ion Flywheels CAES SMES Ultracapacitors 800 $/KW 12 $/KWH 300 $/KW 200$/KWH 350 $/KW 500$/KWH 750 $/KW 12 $/KWH 650 $/KW 1500 … 300 $/KW 3600

Alternative Ragone Plot

Pumped Hydro – Simple In Principle 2000 MW 8 HRS Discharge

Towards Better Batteries  400 WH/KG Goal

Flow Batteries  Scalable !

Engineered Into Buildings

Flywheels Advanced materials, fused silica  900 WH/KG

A Single 25KWH Unit

Small Footprint in Array

CAES – Need Pressure Confined Cavern; 2 Sites Worldwide

SMES Volumetric Energy Density: ½  H 2 In principle reasonable size systems can store up to 1500 MWh of energy. Good for utility-scale applications

Comparison PHCAFLYTHMBATCAPMES PWR EFF80%70%90%85%75%90%95% TiMEHRSHRSMINHRSHRSSECHR

The 10% / 1 HR Solution 25 Luddington Size Pumped Hydro Facilities Grid connected! 100 Million KG of Advanced Batteries (1 Billion KG of AA’s) 300,000 grid connected fused silica flywheels of radius 1 meter and width 0.25 meters 300x300x300 meter cube of compressed air (one helluva scuba tank!)

Dedicated Hydrogen Production 10% solution requires 200 million liters of hydrogen Note that we use about 400 million gallons of gasoline a day 10, MW Wind Turbines located in Western North Dakota could produce 200 million liters of hydrogen every 24 hours

Overall Conclusions Conventional Energy Storage solutions do not scale well to solve increasing gap between average and peak loads Flow batteries or flywheel farms may be practical for some in situ industrial applications SMES can become a utility scale application on short timescales Electricity + Water = Hydrogen

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