Energy Storage for Islanded Microgrids Islanded Grid Resource Center – Webinar on Energy Storage – January, 18, 2015

Marc Mueller-Stoffels, PhD

1

Energy Storage Services !   Power quality - seconds

!   Rapid variability of intermittent renewable energy

!   ‘Sluggishness’ of diesel generators !   Renewable energy smoothing - minutes

!   Spinning reserve !   Fast acting diversion load

!   Renewable energy shifting – hours (to days) !   Diversion load !   Meeting peak demand, when peak

production occurs at other times !   Note: advanced inverters may provide

added benefits – var support, diesel-off capabilities, etc.

2

Energy Storage Types

!  Electro-chemical – Batteries

!  Electro-mechanical – Flywheels, Compressed air, hydro-storage

!  Electro-thermal – Thermal storage heaters, molten salt, steam, ice, brine.

3

Chenahotsprings.com

Energy Storage Cost !   Capital investment

!   Varies significantly !  Energy storage

technology !  Power electronics !  Balance of plant !  Control integration

!   Operation and Maintenance

!   Energy cost !   No ESS is 100%

efficient

4

Altenergystocks.com

0 100 200 3000.27

0.28

0.29

0.3

0.31

Dispatchable Load Size [kW]

Ren

ewab

le P

enet

ratio

n

Important questions !   Can you get away without

energy storage? !   Is demand management

cheaper? !   Can diesels be operated

at lower minimum loading?

!   Can the power quality envelope be widened?

!   What is the least amount of energy storage you need?

!   Do the economics work out?

5

www.energystorageexchange.org

6

More Alaskan Projects

! Kwillingok BESS !  ABB PCS 100 inverter with automotive Li-

Batteries !  Objective: Diesel-off, recently commissioned.

! Kokhanok BESS !  Sustainable Automation GRIDFORM inverter with

VRLA battery !  Objective: Diesel-off, currently offline.

7

ACEP Power Systems Integration !   Inverter-flywheel integration

with Hatch !   Williams Flywheel: 200 kW/

1.5 kWh, composite !   ABB PCS100 Inverter !   Controls by Hatch

!   VRLA-Inverter integration !   BMS development !   Diesel-off testing

!   Liquid metal battery integration with Ambri !   Expected to commence

Summer 2015 !   Previous projects testing flow

batteries

8

Questions?

Marc Mueller-Stoffels, PhD Research Assistant Professor Alaska Center for Energy and Power University of Alaska Fairbanks mmuellerstoffels@alaska.edu ‘Like’ ACEP on Facebook for frequent project updates.

9