
Kelcy Pegler, CEO at US energy storage system integrator FlexGen, takes part in our Year in Review Q&A series.
FlexGen is currently focused on integrating grid-connected battery energy storage system (BESS) assets in the US but was established as a global specialist in microgrids back in 2009.
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That background of integration and control systems was a key differentiator through its move into BESS, and helped it develop what FlexGen claims is a high level of expertise in software for energy applications.
For instance, in September last year the company launched its first US-made battery management system (BMS) into the market at the RE+ industry show, and its service offerings include a Digital Twin technology that allows developers, independent power producers (IPPs) and asset owners to model their projects in virtual space.
FlexGen’s everyday work, as former CCO Yann Brandt described it, is “turning batteries on and keeping them on,” and its suppliers include CATL, with which it signed a 10GWh supply deal in 2022, and Hithium, with which it contracted for 25GWh a year later.
FlexGen CEO Kelcy Pegler looks back on a “transformational year” for energy storage and ahead to the “fundamental shift in power demand” that he believes will shape 2025.
What did 2024 mean for the energy storage industry from your company’s perspective and the bigger picture?
It was a transformative year for energy storage, with the industry focusing increasingly on operational excellence and reliable performance, moving beyond the traditional emphasis on physical hardware and its associated costs.
At FlexGen, independent third-party data confirmed our fleet’s 98% availability in California and Texas was the storage industry’s best performance by 5%, a metric that has become the gold standard as storage assumes a more critical role in grid infrastructure.
US energy storage deployments nearly doubled in 2024 to reach approximately 30GW [of cumulative installations], demonstrating the increasing confidence in storage as a fundamental grid asset.
For FlexGen specifically, we strengthened our position through strategic financing and the most aggressive feature-release schedule in the 15-year history of our HybridOS energy management system (EMS).
Leveraging advancements in artificial intelligence, we have accelerated the capability of our software, enabling faster and more precise decision-making across battery asset operations. At the same time, we’ve simplified the user experience, reducing training and operational hurdles by embedding 15 years of operator expertise into millions of lines of code.
What do you think 2025 will hold, firstly in terms of things to look forward to, but also in terms of challenges ahead?
2025 will be shaped by a fundamental shift in power demand. The explosive growth of data centres is creating unprecedented energy needs, accelerating the deployment of all types of power generation.
But this rapid expansion requires more than just additional power sources—it demands a grid that’s both resilient and reliable. With faster interconnection approvals, lower costs, and software-enabled adaptability to both millisecond operational demands and long-term regulatory shifts, energy storage is proving unmatched in its ability to support the grid’s transformation.
The industry is poised for new records, building on last year’s momentum. What’s particularly exciting is how storage continues to evolve from being viewed as a backup resource to becoming essential for grid reliability and performance. Every grid challenge ahead, from interconnection queues to new generation sources to workforce development, points to an increased adoption of software-first and UI-focused battery storage that will scale in all scenarios.
“Lenders and investors now view availability metrics as key indicators of project success.”
Kelcy Pegler, CEO, FlexGen
The last year has seen incredible growth in energy storage deployments in key markets worldwide, but what are some things that people may not be aware of when considering the development of mature and emerging markets?
While many focus on initial capital costs, the true measure of a storage system’s value over its lifetime is its consistent, reliable operation.
In a recent report by [energy transition data consultancy] Orennia, the returns on battery storage are higher but more variable than those of solar assets. On the other hand, that variability can be significantly reduced through a sophisticated software approach to maximise availability and a proactive operations strategy focused on detecting, evaluating, and resolving issues to minimise downtime.
The evolution of customer requirements is another under-appreciated trend. Early storage adopters focused primarily on duration and capacity.
Today’s customers are much more sophisticated, looking at factors like round-trip efficiency, response time, and system reliability. This shift is driving the industry toward more robust ‘Day 2’ solutions and raising performance standards across the board.
Are there any major market trends that our readers should watch, perhaps related to technology, financing, or other aspects of the industry?
The integration of advanced software, machine learning, and AI technologies is enhancing system performance and reliability through improved predictive maintenance and more sophisticated control strategies.
As diverse generation types and their associated Standard Operating Procedures (SOP’s) flood into operators’ control rooms, simplifying the incredible volume of data into user-friendly, prioritised recommendations will be critical to accelerating the grid transition.
These technological advances, coupled with a philosophy of creating intuitive software to manage robust power operations are helping the entire industry achieve higher performance standards.
On the financing side, we’re seeing increased emphasis on operational track records. Our recent US$75 million revolving credit facility with J.P. Morgan reflects growing confidence in storage companies that can demonstrate consistent, reliable performance. Lenders and investors now view availability metrics as key indicators of project success.
What should the industry’s priorities be in 2025 and beyond?
First, we must focus on standardisation. As the industry matures, we need consistent approaches to measuring and reporting system performance. This will help stakeholders better evaluate storage solutions while driving overall industry improvement.
For instance, when we ask rooms full of current operators what their current availability rate is, the answer is most commonly something like: “I’m not sure, but it’s probably X% +/- 10%,” which demonstrates that it is not yet the North Star metric that it should be.
Second, we need to continue advancing the software and controls that enable high availability rates and lower downtime. The future grid requires unprecedented reliability, and storage is uniquely positioned to provide this capability – but only if we maintain our focus on operational excellence that far exceeds current customer expectations.
Finally, we must invest in workforce development and streamline interconnection processes to support rapid scaling while maintaining performance standards.
Success in these areas will determine how quickly we can deploy storage to meet growing grid demands.