Modeling process for the cost profile of a Energy Management System (EMS)

27 Aug 2021

Modeling is an iterative process that starts with a first estimate of battery specification that is combined with the other inputs to the EMS to deliver a cost profile.

It calculates the lifetime costs and operating revenue for a size of ESS. By repeating the process with a range of different sizes, it’s possible to identify the sweet spot, where the operator will find the optimum balance between revenues and costs during the whole life of the installation or not.

At the heart of modeling is the algorithm that is the same as that used by our battery management systems in the field. It mimics the performance of the ESS down to the level of individual cells, taking account of electrical and thermal performance and electrochemical ageing. It is this direct input of field data that represents the difference between a solution offered by a consultancy and that offered by a battery manufacturer with real-world experience.

Varying the size and specification of the battery changes the cost profile. A smaller ESS will have a lower capital cost but could lead to lower revenues, more penalties, lower compliance with the grid code, or more curtailment losses. It will also alter the system’s operating life.

By calculating the total cost of ownership (TCO) against specification, EverExceed can tailor the size of the ESS to meet our customer’s business objectives and operating environment.

Good thermal management is one of the most important factors, ensuring that the temperature is consistent across the entire ESS. By minimizing temperature variation, the cells and
modules experience a constant rate of aging. In turn this allows for precise prediction of battery performance over its lifetime. It is important to note that accelerated aging of single
modules or branches will impact the performance and lifetime of the complete system.

Other important aspects are to ensure accurate measurement of state of charge (SOC), good SOC management, and ensuring the high-energy efficiency of the battery system itself as
well as the power converter and auxiliary systems such as cooling plant. Together these extend the lifetime of the ESS, enhance performance and optimize the total cost of ownership.

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