REP Storage and Grids 2

Question 1

Which grid service involves an energy storage system automatically responding within seconds to stabilize grid frequency deviations?

Accepted Answer

Frequency regulation

Answer

Peak shaving

Answer

Volt/VAR optimization

Answer

Load following

Question 2

A battery energy storage system (BESS) has a round-trip efficiency of 85%. If 100 MWh is stored, how many MWh are available for discharge?

Accepted Answer

85 MWh

Answer

100 MWh

Answer

15 MWh

Answer

115 MWh

Question 3

What term describes the practice of charging storage systems during low-price periods and discharging during high-price periods to capture wholesale electricity price spreads?

Accepted Answer

Energy arbitrage

Answer

Demand response

Answer

Capacity firming

Answer

Ramp rate control

Question 4

Which interconnection standard governs the technical requirements for connecting distributed energy resources, including storage, to the utility grid in the US?

Accepted Answer

IEEE 1547-2018

Answer

NERC CIP-014

Answer

ANSI C84.1

Answer

NFPA 855

Question 5

In a pumped hydro storage facility, which factor most directly determines the amount of energy that can be stored?

Accepted Answer

Volume of upper reservoir and head height

Answer

Turbine blade diameter

Answer

Penstock pipe diameter

Answer

Generator rotor speed

Question 6

What grid condition is described when voltage levels at distribution nodes fall below acceptable thresholds, often during peak demand?

Accepted Answer

Undervoltage (voltage sag)

Answer

Overvoltage

Answer

Frequency droop

Answer

Phase imbalance

Question 7

Which storage technology is best characterized by very high cycle life, fast response, and suitability for short-duration, high-power applications like UPS and frequency regulation?

Accepted Answer

Supercapacitors (ultracapacitors)

Answer

Lead-acid batteries

Answer

Compressed air energy storage

Answer

Vanadium redox flow batteries