Relectrify's AC1 Goes Live in South Australia: What the Inverterless Architecture Actually Does

The inverter is one of those components that everyone in battery storage accepts as a given - a necessary piece of power electronics that converts DC from the cells into grid-compliant AC. Relectrify, a Melbourne-based startup, has spent years arguing that assumption is wrong. This week, it put hardware in the ground to prove it.

Melbourne-based battery technology company Relectrify has installed its first AC1 battery energy storage system (BESS) in Renmark, South Australia, in partnership with YES Energy.^[1] The Renmark unit is sized at 250 kVA and 1,089 kWh usable, and it is the first commercial deployment of a system that generates grid-compliant AC power without a conventional inverter.^[1]

That distinction matters more than it might sound.

What "Inverterless" Actually Means - and What It Doesn't

The term needs unpacking before the claims around it can be evaluated. A conventional BESS stores energy as direct current and requires a power conversion system (PCS) - the inverter - to translate that DC into the AC the grid expects. Conventional battery systems store energy as direct current and require inverters to convert this power to alternating current for grid connection, adding complexity, cost, and potential failure points to the system.

Relectrify's approach is different in architecture, but it is not magic. CEO Jeff Renaud has acknowledged that the AC1 is using a software inverter - "you still have to convert from DC to AC power and we're doing it purely with software rather than using conventional pieces of equipment." The distinction is that there is no separate inverter hardware. Instead, the AC1 uses cell-level semiconductor circuitry to individually control battery cells at high frequency, directly producing an alternating current waveform - eliminating the need for a separate inverter as part of the system design.

The core technology is branded CellSwitch. It provides individual monitoring and control of nearly 4,000 battery cells within each AC1 unit - a level of granularity the company says is unmatched by other BESS on the market.

The Three Operational Claims ARENA Is Paying to Test

The Renmark installation is not a standalone project. It forms part of Relectrify's More Energy Project, a AU$61.1 million programme with AU$25 million (US$16.23 million) contributed by ARENA under its Advancing Renewables Program, running from August 2025 until May 2028, with Relectrify targeting a cumulative nameplate capacity of up to 100 MWh across customer sites in Australia.

ARENA is not funding this on faith. The funding is intended to generate field performance data that builds market confidence in Relectrify's battery management system technology, ahead of wider commercialisation. The agency has identified three specific advantages it expects the inverterless design to demonstrate at scale:

Lower capex from the absence of a separate inverter; improved usable lifetime battery capacity through individual cell management; and lower opex from the ability to identify and replace malfunctioning cells with precision.

Each of those deserves scrutiny.

On capex: The inverter is not a trivial line item in a conventional BESS budget. The power conversion system is the second-largest hardware cost in a conventional BESS, typically representing 15-25% of total hardware expenditure - the component that converts DC battery power to AC grid power and vice versa. Removing that hardware layer has a real cost consequence, though the cell-level semiconductor circuitry that replaces it is not free either. The net capex saving is something the More Energy Project deployments will need to quantify in real-world conditions.

On lifetime energy: Relectrify claims the AC1 delivers 20% more energy over its lifetime compared to a conventional BESS. The mechanism is cell-level management: rather than the entire string being limited by its weakest cell, each cell is independently optimised. The company says the AC1 retains 40% more of its original capacity after 20 years of daily cycling, and reliably delivers 99% of available energy every time it is cycled. Those are headline numbers from the company's own materials - the ARENA field programme is the mechanism that will either validate or complicate them.

On opex: Cells are continuously monitored for faults and deviations, and any anomalous cell is bypassed without impacting the operation of the battery. In a conventional string architecture, a single degraded cell can drag down an entire module. The ability to isolate and replace individual cells without taking the system offline is a genuine operational advantage - if the cell-level electronics themselves prove reliable over a decade-plus asset life.

The Renmark Site and What YES Energy Brings

Renmark is a regional centre in South Australia's Riverland - not a grid edge location, but not a major load hub either. The choice of a regional commercial and industrial site is deliberate: Relectrify CEO Jeff Renaud has described the AC1 as being designed to fill the "missing middle" of commercial and industrial energy users in Australia's energy transition.

YES Energy is a South Australia-based turnkey renewable energy solutions company^[1] - the kind of integrator that handles site-level installation and commissioning. The partnership structure is consistent with Relectrify's model: design the cell-level technology, work with local integrators for deployment.

Before the Renmark unit was switched on, the AC1 had to clear a certification hurdle that is easy to underestimate. The system has been certified to both International Electrotechnical Commission (IEC) standards and the Australian grid connection standard AS/NZS 4777. AS/NZS 4777 governs grid connection of energy systems via inverters - the irony of an inverterless system needing to pass inverter connection standards is not lost on the engineers involved, but it is the right test. The grid does not care how the AC is generated; it cares that the waveform is compliant.

The Broader Programme Context

The More Energy Project sits within a larger policy architecture. The AU$25 million funding sits alongside ARENA's AU$500 million Battery Breakthrough Initiative, which supports domestic battery manufacturing and deployment, and the federal government's broader National Battery Strategy, which targets a globally competitive Australian battery industry by 2035.

Relectrify is not purely an Australian play. The AC1's international rollout is also underway, with Relectrify having entered the Taiwanese market, where the system's proprietary electronics are manufactured and its components assembled. That manufacturing footprint matters: the electronics are designed in Melbourne and built in Taiwan, which gives the company access to a mature precision electronics supply chain while keeping IP onshore.

The company's equity base reflects the strategic interest in the technology. Relectrify completed a $19 million equity funding round featuring backing from six existing investors, including Virescent Ventures, and a new minority investment from Houston, Texas-based Fortune 500 company NRG Energy. NRG's involvement is worth noting - a US utility-scale power company taking a minority stake in an Australian cell-level BMS startup is a signal about where large energy players think the technology is heading.

What the Renmark Installation Doesn't Tell Us Yet

This is a first installation, not a validated fleet. The More Energy Project runs until May 2028, and the 100 MWh target across multiple customer sites is the dataset that will actually answer the hard questions:

• Does the cell-level semiconductor circuitry maintain reliability over multi-year cycling at the claimed depth of discharge?
• What does the real-world capex delta look like versus a conventional LFP BESS of equivalent size, once the CellSwitch electronics are priced in?
• How does the system perform in grid-forming or ancillary service contexts - particularly relevant given AEMO's ongoing work on system strength requirements?

The 20% lifetime energy uplift claim and the 40% capacity retention figure after 20 years are projections, not measured outcomes. The Renmark site, and the sites that follow it across the More Energy Project, are the mechanism for converting those projections into bankable data.

The More Energy Project targets a cumulative nameplate capacity of up to 100 MWh deployed across Australian customer sites by May 2028. That is a modest volume by grid-scale standards - a single utility project in Australia routinely exceeds it. But for a technology at this stage of commercialisation, 100 MWh of field data across diverse C&I sites is exactly what lenders and offtakers need before they will sign long-term contracts.

The Renmark installation is the first data point. The architecture is genuinely novel. The performance claims are plausible but unproven at scale. Watch the field data.