EESS

Under the latest MCS standards, particularly MCS 032:2025, there are specific guidelines regarding battery degradation when performing system performance calculations for Electrical Energy Storage Systems (EESS).([MCS][1])

🔋 Battery Degradation in Performance Calculations

While MIS 3012:2025 focuses on the installation aspects of battery storage systems, MCS 032:2025 provides detailed methodologies for estimating system performance, including considerations for battery degradation.

Key points include:

• Cycle Limitations: To account for battery degradation over time, MCS limits the number of cycles assumed in annual energy discharge calculations to 2 cycles per day, totaling 730 cycles per year. This conservative approach ensures that performance estimates remain realistic over the system's lifespan. ([MCS][1])

• Usable Capacity Allocation: When calculating performance, it's essential to determine the proportion of the battery's usable capacity allocated for self-consumption versus other services (e.g., backup power, grid services). The sum of these allocations should not exceed 100% of the total usable capacity. ([MCS][1])

• Performance Estimates: Installers should provide clear documentation on how battery degradation impacts system performance over time, ensuring transparency with clients regarding expected energy savings and system efficiency.

📄 Documentation and Compliance

To remain compliant with MCS standards:

• Performance Calculations: Ensure that all performance estimates incorporate the 730 cycles per year limitation and clearly outline assumptions made regarding battery degradation.([MCS][1])

• Customer Communication: Provide clients with detailed explanations of how battery degradation may affect system performance, including any assumptions made in the calculations.

• Record Keeping: Maintain thorough records of all calculations and justifications related to battery degradation for auditing purposes.([MCS][2])