NABCEP Battery Storage Systems & Energy Storage 3

Question 1

What is the typical usable capacity percentage for a lithium iron phosphate (LFP) battery relative to its nameplate capacity?

Accepted Answer

90–100%

Answer

LFP batteries can typically be used at 90–100% of their nameplate capacity due to their flat discharge curve and ability to tolerate high DoD without significant degradation.

Question 2

IEEE 1547 is directly relevant to battery storage systems connected to the utility grid because it governs:

Accepted Answer

Distributed energy resource interconnection requirements

Answer

IEEE 1547 sets the standard for interconnecting distributed energy resources (DERs), including battery storage systems, to the electric power system, covering voltage, frequency, and protection requirements.

Question 3

A battery storage system is rated at 10 kWh with a round-trip efficiency of 92%. How much energy must be put into the battery to retrieve 9.2 kWh?

Accepted Answer

10 kWh

Answer

To retrieve 9.2 kWh at 92% round-trip efficiency, you divide 9.2 by 0.92, which equals exactly 10 kWh of energy that must be charged into the battery.

Question 4

Which interconnection mode allows a battery storage system to operate in isolation from the grid to serve local loads during a utility outage?

Accepted Answer

Island mode (off-grid mode)

Answer

Island mode (also called off-grid mode) allows the battery inverter to establish its own voltage and frequency reference to power loads without utility grid support during an outage.

Question 5

Per NFPA 855, what is the maximum allowable energy capacity for a single lithium-ion battery storage unit installed in a residential occupancy without requiring additional separation or suppression?

Accepted Answer

20 kWh

Answer

NFPA 855 limits individual lithium-ion ESS units in dwelling units to 20 kWh without additional fire suppression or separation requirements, with a maximum aggregate of 40 kWh per dwelling.

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

NABCEP Battery Storage Systems & Energy Storage 3