Bob HebnerDirector , Center for

ElectromechanicsUniversity of Texas at Austin

100+ researchers into energy storage, smart grid, and energy technology

Working for seven years on “Smart Grid” for DoD

Storage programs in flywheels, batteries, ultracaps, compressed air, and thermal

Reconfiguration approach handles:

• Fuel minimization

• Power system protection• Damage mitigation

Reconfiguration via optimization

Using a power objective function

Subject to:

Attributes• Permit active participation by consumers • Accommodate generation and storage

options • Enable new products, services, and markets • Provide power quality • Operate efficiently • Reconfigure in response to system

disturbances Technology

• Traditional power engineering• Computing• Telecommunications

Top down• Large scale wind farms• Smart meters

Bottom up• Microgrids

Neighborhoods Industry Universities DoD facilities Urban environments

Sources connected to loads through a grid• Pearl Street

Operate at 60Hz• Texas storage

Today’s grid• Capacity constrained• Loads demand clean power• Cascading failure

Charge-discharge rate Turnaround efficiency Storage losses Lifecycle cost Size/weight

• High rates and depths of discharges,- Flywheels have best properties.

• Long storage times and low rates and depths of discharge

- Batteries usually are best• Between the extremes,

-There are many competitive solutions

Storage OptionSelf Discharge time (1)

Round trip efficiency

Flywheel 2-12 hours 0.9

Ultracapacitor 3% per day = 1 month 0.8

Battery 3% per day = 1 month (NiCd) 0.7

Power quality• Sensitive loads• Increase use of renewables

Diurnal shifting• Broader use of renewables• Greater return on investment

Frequency stabilization• Improved system reliability• Increase use of renewables

Plug-in hybrids Increase effective grid capacity Provide reconfiguration support

Flywheel – 1 MW, 3 minutes

Key technology advances for storage include:• Rapid charge/discharge batteries with long

life• Lower loss magnetic bearings• Stronger composites to reduce windage loss• Innovative control strategies• Advanced scaling approaches

Transmission companies Generating companies Distribution companies Regulators Storage manufacturers Microgrid developers

Different needs for storage, different definitions of success

Focus on metering• Positive: Opens opportunity for innovative

local storage• Negative: May give “Smart Grid” a bad

name Storage Stimulus

• Positive: Lowers the first cost barrier for innovative storage technology

• Negative: Wrong technology/application choices may poison the well

Storage critical for “Smart Grid”• Most agree, but assume different

applications Excellent storage choices exist today With R&D, better choices will exist in

the future Evolution of “Smart Grid” is a work in

progress• Storage can help shape the evolution