Why Power Conversion Is the Strategic Asset the Energy Transition Cannot Afford to Get Wrong

I began my career many years ago in the same transformer factory that my father ran in Cordoba, Spain. My brother still works there. When I moved into my role as head of Hitachi Energy's Power Conversion Solutions business a few years ago, the physics were familiar. But the strategic context was not. The transformer is foundational infrastructure; extraordinarily reliable and designed to perform the same function for decades with minimal intervention.

The modern power converter is a fundamentally different kind of asset. Its role in the energy system is still being defined but full of possibility.

For the better part of a century, the electricity system operated on a centralized model that moved primarily in one direction. Large synchronous generators (coal, gas, nuclear) produced power in alternating AC current. That power flowed through transformers, across networks, and into homes and industries that consumed it in the same form. Critically, those enormous rotating machines provided something that underpins everything: physical inertia. The sheer mass of spinning steel dampened frequency deviations, and gave system operators the time and margin to respond to events before they cascaded. The synchronous nature of those machines also contributed to voltage stability and reactive power support across the network.

The increasing integration of distributed renewable energy resources and the broader electrification of the economy have not just added complexity to that model. They are reshaping many of its core assumptions. Solar generation is inherently DC. Battery storage operates in DC. The fastest-growing new loads on the grid, data centers, EV charging infrastructure, and advanced industrial facilities also increasingly rely on DC internally. The result is a system in a state of continuous, high-speed translation between two electrical domains, at a scale and geographic distribution that the original grid architecture was never designed to accommodate.

Power converters perform that translation. But to describe them solely as translation devices is to miss what has fundamentally changed. A converter is really an active, software-driven system. It does not simply move electricity; it constantly interacts and reacts with the grid, managing frequency, regulating voltage, controlling reactive power, and responding to disturbances in milliseconds. As synchronous generation declines and system inertia is reduced, the converter has stepped into the role that was once provided by large rotating machines. In effect, it assumes a fundamental stability control functionality for the modern grid.

The scale of this implication is significant. The IEA projects that battery storage capacity will grow sixfold by 2030. Each of those installations depends on a power converter to interface with the grid, to respond to system events, and to deliver the performance that financiers, operators, and regulators expect. The converter is not just supporting the energy transition. In a very real sense, it is executing it.

Recognizing the converter as an active, strategic asset rather than a peripheral component fundamentally changes the questions worth asking about it. Performance under nominal conditions is a baseline, not a differentiator. The more revealing measure is how a converter behaves when the grid is under stress, during a fault, a frequency event, or a sudden loss of generation elsewhere in the system. In a grid with diminishing inertia, those moments arrive faster and with less margin for error than in previous decades. How power electronics are designed, controlled, and tested for these conditions is where the real engineering distinction lies.

There is also a second dimension that has moved, quite rapidly, from background concern to boardroom conversation: security. Converters are digitally connected systems embedded in critical national infrastructure, and the control software that governs their behavior is as consequential as the hardware itself. As grids become more converter-dominated and high-value, power-intensive sectors like data centers become more grid-dependent, the origin, design integrity, and cybersecurity posture of those devices carry implications that extend well beyond technical performance. Regulators across multiple jurisdictions have already begun to formalize this view.

The third dimension is time. A battery energy storage system is not a short-cycle asset. It is designed to operate for 20 years or more, across grid code revisions, market rule changes, and technology generations that cannot be fully anticipated at the point of commissioning. The question of who stands behind a converter over that horizon, with the engineering depth, the service capability, and the financial commitment to sustain performance across the full asset life, is one that sophisticated asset owners and project financiers are increasingly asking at the front end of procurement, not as an afterthought.

Abstract principles quickly become concrete when they are tested against real operating conditions. At Ulinda Park in Queensland, Australia, Hitachi Energy has delivered a 155 MW / 298 MWh battery energy storage system for Akaysha Energy. That means 52 converters operating in one of the world’s most demanding electricity markets, where participation in the country’s Frequency Control Ancillary Services requires consistent, predictable performance under conditions that are anything but routine.

What distinguishes Ulinda Park as a reference point is not the scale of the installation, but the nature of the commitment behind it. Alongside the technical delivery, Hitachi Energy and Akaysha Energy entered into a 20-year Long-Term Service Agreement covering continuous monitoring, preventive and corrective maintenance, 24/7 remote and on-site support, with defined accountability for availability and performance across the full lifecycle of the asset. Delivered through Hitachi Energy's HMAX Energy suite, an AI-powered framework that combines asset intelligence, digital service workflows, and expert support, the agreement is built around planning, prediction, and prevention across the full asset life. That is not a warranty. It is a partnership structured around outcomes over time, with the OEM carrying responsibility for the system’s performance in the market, not just its condition at handover.

The technology itself continues to advance. Power electronics are beginning to deliver meaningful gains in efficiency and thermal performance, with direct implications for converter footprint, operational cost, and grid-edge deployment. AI-driven control algorithms are moving from research to operational deployment, enabling grids to manage the complexity and speed of converter-dominated systems at a scale that traditional deterministic control logic cannot easily match. And digitalization is transforming asset management as well, shifting maintenance from calendar-based schedules to condition-based intervention, and enabling the kind of long-term performance visibility that underpins 20-year service commitments like the one at Ulinda Park.

But the more important point is structural. The assets being specified and commissioned today, the converter fleets that will underpin solar farms, battery systems, and grid infrastructure across the next investment cycle, will still be operating in the mid-2040s.

The grid they will be asked to support by that point will likely be increasingly dynamic, more converter-dominated, and more dependent on the intelligence embedded in those systems than the grid of today. The decisions being made now about technology selection, supplier relationships, and service models are therefore not procurement decisions in the conventional sense. They are long-duration infrastructure commitments, and they carry consequences that compound over time.

The energy transition tends to be measured in the units that are easiest to count; gigawatts of renewable capacity installed, gigawatt hours of storage connected, and percentages of clean energy on the system. Those metrics matter. But grid reliability is determined at a different level of resolution: within the systems that balance supply and demand in real time, maintain frequency and voltage within tolerance during disturbances, and that sustain performance not just at commissioning but over decades of operation in conditions that were not fully modelled at the design stage.

I have spent nearly three decades watching power infrastructure evolve, first in transformers, and now in power conversion. What I observe is a technology that has moved from the periphery of grid design to its operational center, and the broader conversation about the energy transition has yet to fully catch up. The converter is no longer simply a device installed alongside solar panels or batteries. It is the system that determines how those assets interact with the grid, where advanced controls and power electronics work together to manage performance and stability under real operating conditions.

Gigawatts and gigawatt hours define ambition. The converter determines whether that ambition is realized. The converter is the brain of the installation, and what you choose to place at the center of your grid, and who stands behind it over its lifetime, is one of the most consequential decisions in the energy transition.