Which of the following is NOT listed as a benefit of battery energy storage systems?

• A. Energy efficiency
• B. Reliability
• C. Cost savings
• D. Increased emissions

Answer: (D)

Battery energy storage systems store electricity to use when it’s most needed, unlocking several practical benefits for the grid and for building operations. They are valued for energy efficiency, reliability, and cost savings. Energy efficiency comes from aligning when energy is produced or purchased with when it’s consumed, reducing waste and making better use of generation. Reliability is improved because the storage can supply power during outages, voltage dips, or transmission constraints, keeping critical systems up and running. Cost savings come from reducing peak demand charges, leveraging cheaper off-peak energy, and delaying investments in new generation or grid infrastructure.

Increased emissions, however, is not a benefit of these systems. In practice, battery storage supports cleaner energy use by enabling higher penetration of renewable sources and reducing reliance on fossil-fuel peakers, which tends to lower emissions rather than raise them.