Which of the following features can reduce O & M costs?

The exact extract asks which feature can reduce O & M costs. The correct answer is Automatic SOC calibration. SOC means state of charge, and calibration is important in battery energy storage systems because inaccurate SOC estimation causes inefficient charge/discharge management, maintenance intervention, and possible capacity underutilization. Huawei’s Smart String ESS positioning specifically identifies automatic SOC calibration as an O & M cost-reduction feature. Huawei states that automatic SOC calibration minimizes manual interventions and reduces operational costs, while other Huawei ESS material states that automatic SOC calibration eliminates the need for onsite O & M by experts and supports higher comprehensive energy efficiency. The other options do not directly match the “reduce O & M costs” wording. On/off-grid switchover is mainly a continuity and power-supply resilience feature. TOU is an energy-cost optimization strategy. Top explosion venting is a safety-pressure-relief design. Therefore, the feature directly associated with reduced O & M workload and lower maintenance cost is automatic SOC calibration. References: Huawei Smart String Grid Forming ESS Solution and FusionSolar Smart String ESS material.