REP - Certified Renewable Energy Professional Energy Storage and Grids Questions and Answers

Question 1

A utility is experiencing significant grid instability due to the high penetration of intermittent renewable energy sources.
Which of the following energy storage services is most crucial for maintaining a balance between electricity supply and demand on a second-by-second basis?

Accepted Answer

Frequency regulation

Answer

Peak shaving

Answer

Black start capability

Answer

Energy arbitrage

Question 2

A remote island microgrid, powered primarily by a solar PV array, needs an energy storage solution to provide power throughout the night and ensure grid stability. The system must be capable of rapid charge/discharge cycles to smooth out passing clouds during the day. Which technology is best suited for this application?

Accepted Answer

Lithium-ion battery energy storage system (BESS)

Answer

Pumped-hydro storage

Answer

Compressed Air Energy Storage (CAES)

Answer

Flywheel energy storage

Question 3

Which of the following is a primary challenge associated with integrating large-scale renewable energy into traditional power grids?

Accepted Answer

Reduced system inertia

Answer

Lack of fuel price volatility

Answer

Consistently high capacity factor

Answer

Decreased need for transmission infrastructure

Question 4

Compressed Air Energy Storage (CAES) is being considered for a large-scale, long-duration storage project. In a diabatic CAES system, what is typically required during the energy discharge (expansion) phase to increase the efficiency and power output?

Accepted Answer

Burning a fuel, like natural gas, to heat the air

Answer

A secondary water reservoir

Answer

Direct exposure to sunlight

Answer

A large array of photovoltaic panels

Question 5

A grid operator needs a storage asset specifically for providing very fast, high-power bursts of energy to regulate grid frequency and improve power quality, with a very high cycle life being a top priority. Which technology is uniquely suited for this high-power, short-duration application?

Accepted Answer

Flywheel energy storage

Answer

Pumped-hydro storage

Answer

Lead-acid batteries

Answer

Hydrogen fuel cells

Question 6

When comparing pumped-hydro storage (PHS) with battery energy storage systems (BESS) for grid-scale applications, what is a key advantage of PHS?

Accepted Answer

Longer operational lifespan and lower levelized cost of storage

Answer

Faster response time for frequency regulation

Answer

Geographical location flexibility

Answer

Lower initial capital cost per kWh