Working closely to setup large-scale Lithium battery based Energy Storage System (ESS) for a wide variety of main grid, weak grid and micro grid installations; EverExceed has significant experience and insight on the real-world operation and optimization of energy storage technology.

The most important consideration for any ESS is to view it as part of a whole system rather than as a standalone component.

Different aspects of the environment can have a significant impact on the whole life cost of an ESS, which is built up from its capital cost, maintenance and operational costs and the cost of curtailments and outages.

Finding the optimum size for an ESS requires the development of an Energy Management System (EMS), which itself needs many of inputs;

The first set of inputs is site specific. They include the limitations of the grid code and local legislation as well as measured data on the wind or solar power output. It’s important to use high resolution survey results from the actual site over a period of several months - an ideally an entire year - to reflect seasonal changes. Using hourly data is sufficient for a high-level approach, but may lead to inaccurate capacity, life time and performance results, because the hourly averaged power of a PV or wind plant will obscure the short-term variations determining the ESS operation profile. Typically, data with a granularity of 1 second to a maximum 10 min is used for precise modeling.

High resolution data considering local geography and variability is key to achieve an accurate sizing of the ESS, which in turn achieves better financial performance.

The second set of inputs is the customer’s objectives for the plant’s power output – basically the mode of operation, which can include one or more of the roles explained above. These inputs must also include precise technical parameters and limits such as desired ramp rate, maximum power at grid connection point, provisions for frequency support etc. Furthermore, economic variables like the plant’s remuneration scheme must be known, including cost of outages, penalties for deviations from the specification, etc.

Finally, at EverExceed we can contribute our deep understanding of Lithium battery based energy storage technology, including energy, charge and discharge power capacities and the effect of aging on the lithium iron phosphate battery electrochemistry.

Combined with modeling, these factors determine the cost profile, made up of operating revenues and penalties to balance lifetime costs, asset lifetime, OPEX and CAPEX costs.