Beyond Operation: Why Long-Term Performance of BESS projects Depends on the Careful Design of the Power Plant Controller
IHI Terrasun’s advanced power plant control software, Assured Controlstm, ensures that Battery Energy Storage Systems (BESS) projects remain reliable and efficient throughout their lifetime.
BESS projects have become an essential component of the modern energy grid, facilitating the adoption and proliferation of renewable energy and enhancing grid stability. But as BESS installations grow, the challenge is about getting each site to Commercial Operation Date (COD) and then ensuring their long-term stable operation and performance throughout their lifecycle. For IHI Terrasun, the answer to this problem lies in the design of Assured Controlstm, the company’s proprietary solar and BESS power plant controls software. Assured Controls is designed to operate at a high level of reliability and resilience, managing power output of the equipment to meet required discharge or charge amount, solar production (where available) and balancing operation across the whole site. The controller is purposefully designed in a modular way that allows expansion of functions for evolving grid requirements and expansion, either in the form of additional units or for BESS augmentation to the site.
There is a great deal of value for energy storage project developers, owners and operators to choose a system integrator that develops their own power plant control software: it makes the project integration process more efficient, reliable, and seamless. IHI Terrasun’s team is nimble and more adaptable to challenges presented with Original Equipment Manufacturer (OEM) equipment, evolving grid requirements, and new ancillary services because we develop our Assured Controls platform. After all, the equipment is only as good as the control system that runs it.
Keeping Battery and Inverter Equipment in Check
The primary role of a power plant controller is to deliver on the required set points sent through the Automatic Generation Control (AGC) command while ensuring that the equipment used for operation – batteries and inverters – do not exceed their operational parameters or capabilities. The controller must monitor critical parameters like current limits, battery cell voltages, and battery state of charge (SOC), ensuring safe and efficient operation of the project.
IHI Terrasun’s software regulates charge and discharge rates based on available energy levels, ensuring state of charge remains in balance within the overall system and to ensure optimal system performance. Ensuring this balanced state of charge across all battery systems maximizes the energy the plant can deliver.
Advancing Solar-Battery Hybrid Controls
IHI Terrasun’s control software can manage both the solar and battery systems in an AC-coupled or DC-coupled configuration, offering operators and developers flexibility in how they choose to integrate their solar assets into the overall site design.
Our proprietary solar management algorithm allows the plant to ramp up solar power in a controlled way, even in the absence of BESS availability, to avoid overshooting the grid’s setpoint, which could result in penalties. This precise control offers better alignment with grid stability requirements, ensuring predictable and smooth operation.
Visualizing Plant Data for Efficient Site Management
IHI Terrasun’s human-machine interface (HMI) allows operators to have a full view of the BESS (and solar, if present) power plant and its current operational status, isolate parts for maintenance or downtime with minimal disruption to the rest of the system. Through the HMI, the plant operator can reset or shut down inverters and battery systems with a few simple commands, and when necessary, even operate individual units in manual control. Whether the system is already in operation or is scheduled to operate later, the control system automatically redistributes away from offline equipment load to maintain the plant’s overall performance.
Creating Resilient Control Systems
While IHI Terrasun’s controls minimize the risk of equipment fault conditions, some system faults are unavoidable. Assured Controls is designed to ensure stability even in the event of equipment failure or even losing an entire block’s worth of inverters and batteries. The controller will adjust required power output away from the faulting or offline equipment to keep smooth operation and maintain stability throughout the rest of the power plant.
This fault tolerance and isolation is crucial to maintaining grid contributions and preventing project downtime, which can result in penalties to the owner operator or grid instability. Fault tolerance pairs with strategic isolation: if a block or circuit stops operating, it is essential that the software can isolate it from the others so it can be repaired, either through remote action or onsite, while ensuring the remaining assets on site are used to their full capability.
Managing Battery Augmentation and Scalability
Over time, batteries degrade requiring augmentation to maintain the plant’s rated energy capacity. IHI Terrasun’s Assured Controls software is built to manage battery augmentation seamlessly. Whether adding one battery or a whole new block or circuit, the software adjusts to operate with the new configuration, without requiring a separate software development project.
The software at IHI Terrasun monitors and controls the output of individual battery strings to ensure the older batteries are not overburdened, preserving overall system longevity. Adding DC-DC converters allows for more granular control of new batteries, which can further optimize plant performance.
Adhering to Grid Code Compliance and Flexibility
Whether managed by Independent System Operators (ISOs), Regional Transmission Operators (RTOs) or local Utilities, each electrical grid region has different rules and regulations for power plants. IHI Terrasun’s software is designed to meet today’s grid code while also being adaptable to future changes. This flexibility ensures the BESS power plant remains operational and compliant as renewable energy integration grows, and new services emerge.
We also build in flexibility for new revenue opportunities. As grid regulations evolve, plant operators may need or want to offer new services to the grid which do not currently exist or are not currently required. Our ability to update the controls software gives power plant owners and operators a competitive edge by allowing them to meet new grid requirements without extensive coordination or the need to hire an outside firm that may not understand the operation of the project nor have insights into the onsite equipment.
Assured Insights
IHI Terrasun’s Assured Insightstm platform offers intelligent dashboards that provide a window into the critical data necessary for monitoring site operation, providing plant operators and asset managers with an at-a-glance view of the site’s performance and the issues that are most heavily impacting site performance. The dashboards include historical data – how did the site perform over a configurable block of time – while also enabling live views into how the system is operating currently. This data is critical for both day-to-day operations and troubleshooting, offering transparency and control over how the plant is performing. The ability to see both past performance and current operation is an important piece for the IHI Terrasun Assured Servicestm team to keep the project operational.
Ensuring Stability and Maximizing Performance
At the core of a reliable and efficient BESS is a control system that offers stable operation, easy commissioning, fault avoidance, adaptability, and comprehensive monitoring. IHI Terrasun’s Assured Controls ensures that power plants can weather equipment failure, faults due to weather events, adapt to evolving grid codes, and manage the challenges of battery degradation with minimal disruption to operations.
For power plant owners and developers, these capabilities translate into long-term operability, sustained performance, and a return on financial investment. By maximizing the efficiency of their systems and squeezing out every possible electron*, IHI Terrasun is not only helping achieve project ROI but also contributing to a more sustainable, reliable energy grid.
* To our technical audience, we note that output of BESS systems is measured in coulombs, not electrons. Read more about the measurement of charge on Wikipedia.
