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

Frequency regulation requires fast-responding assets (often within 4 seconds) to correct imbalances between generation and load, maintaining grid frequency near 60 Hz.

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

Round-trip efficiency represents energy out divided by energy in, so 100 MWh × 0.85 = 85 MWh delivered to the grid.

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

Energy arbitrage exploits time-of-use price differentials by storing cheap off-peak energy and selling it back during expensive peak hours.

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

IEEE 1547-2018 sets the technical requirements and testing procedures for interconnecting distributed energy resources (DERs) to the electric power system.

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

Stored energy in pumped hydro equals mass × gravity × head height, so both reservoir volume (mass of water) and elevation difference (head) are the primary determinants.

(REP) Certified Renewable Energy Professional Practice Test

(REP) Certified Renewable Energy Professional Practice Test

REP Storage and Grids 2