In grids increasingly dominated by renewables, grid-forming technology is emerging as critical tool for maintaining stability and ensuring reliable power system operation. In this interview with ESS News, Rui Sun, Sungrow’s Deputy General Manager-Grid Technology Center, explains how grid-forming works, why it matters, and where the technology is already proving its value. He elaborates on technical challenges, regulatory gaps, and why grid-forming could soon become the new industry standard.
One of the reasons we started this conversation was the paper Sungrow released on grid-forming technology. Could you walk us through why you published it and what it covers?
Of course. We released the paper to share the insights and technical progress we’ve made in grid-forming technology. As more inverter-based resources connect to power systems globally, we recognized the need to provide a clear overview of what grid-forming actually involves – not just as a control concept but as a multi-layered integration of hardware, software, and system-level engineering. The paper highlights how we replicate the fundamental behaviors of synchronous generators, such as inertia and damping, while maintaining the flexibility of power electronics. It’s also an effort to contribute to industry-wide understanding and collaboration.
How long has grid-forming been in development, and what has the path looked like for Sungrow?
The concept dates back one or two decades. The industry has been working on its implementation, and different manufacturers may take slightly different approaches. At Sungrow, our journey has focused on building a solid technological foundation that merges the physics of traditional generation with the advantages of modern inverter systems. That includes everything from frequency response and short-circuit support to thermal management and multi-layer control architectures. Our aim has always been to bring stability, scalability, and interoperability to complex power systems—on- and off-grid.
Speaking of off-grid, would you say that’s where this technology first took hold?
Yes, that’s correct. Many early implementations were in off-grid or islanded systems – environments where maintaining voltage and frequency stability without a central grid is especially challenging. But now we see the same needs growing in grid-connected environments, particularly as renewable penetration increases and conventional synchronous machines retire.
How do grid-forming inverters compare with synchronous generators when it comes to real-world disturbance response?
Functionally, grid-forming inverters aim to replicate the voltage-source behavior of synchronous machines. They provide inertia-like response, frequency regulation, voltage control, and even fault ride-through. The difference lies in the hardware: synchronous generators are electromechanical, while inverters are software-based devices. This means we have to carefully design control strategies—and sometimes enhance hardware—to achieve similar responses. For example, we’ve developed more efficient cooling systems and cell balancing schemes to handle the frequent cycling that grid-forming entails.
How do the costs compare to synchronous generators, especially considering operation and maintenance?
Synchronous machines have high maintenance due to moving parts and prime movers. Our inverter systems – for both PV and energy storage fields – are modular, have no moving parts, and are easier to monitor and upgrade. The ability to reprogram functionality via firmware updates is a major advantage. In the long run, grid-forming inverters offer a more cost-effective and flexible solution, especially as requirements change.
What are the current barriers to wider adoption – technical, regulatory, or economic?
All three, to some degree. Technically, it’s more complex to implement and scale grid-forming systems. Regulatory environments are fragmented, though that’s improving. Economic is less a concern. Grid-forming inverters offer long-term value through lower maintenance, higher flexibility, and firmware upgradeability. Meanwhile the manufacturers are striving to reduce the cost the technology through more maturity. One of the biggest challenges is operational experience – this is still a relatively new technology, and we need more time and data to build confidence across the industry.
How different are regulatory requirements across markets for grid-forming technology?
They vary quite a bit. China, for example, has issued regulations around frequency response and short-circuit behavior. Germany will require inertia services from 2026. The UK’s grid code includes specific provisions for grid-forming performance. Australia is ahead in many ways, with detailed performance guidelines and a testing framework. North America is catching up, particularly in states like Texas. While requirements differ, we see common threads – frequency and voltage stability, harmonic control, and the ability to ride through faults under weak grid condition. That’s why we design our systems with a flexible but robust control layer that can be tailored for different markets.
Are there challenges when deploying grid-forming technology at large scale?
Yes, especially in parallel operation. Each inverter operates as an independent voltage source, so coordinating them without instability is complex. We address this using advanced virtual impedance and synchronization techniques to manage electrical distance and load sharing. Also, inverter-based systems must meet short-circuit and overload requirements – areas where traditional generators were considered an edge due to their mechanical mass. We’ve developed robust hardware to overcome these challenges and proven it in large installations. In the end, it’s a fair game to play for different generation formats.
Do you expect grid-forming to replace grid-following technologies completely, or is there an optimal mix?
That’s a great question. Right now, grid-forming is rapidly gaining ground because we need greater grid stability. As we’ve seen in incidents like the Spain blackout, having more grid-forming resources online could have helped mitigate the impact. While some argue for a hybrid approach, we believe grid-forming will become the default for new projects – especially as system operators move toward stricter requirements. Economically, it still comes at a premium, but the functionality and future-proofing justify the investment. Over time, the mix may shift toward grid-forming dominance.
Could you highlight one of your major projects using grid-forming technology?
Absolutely. A great example is the Amaala resort microgrid in Saudi Arabia. It’s a complex islanded system combining PV, battery storage, and even backup generators. We supplied 125 MW of PV inverters and 160 MW/760 MWh of energy storage to this project. It operates entirely off-grid, meaning system stability requirements are very high. Grid-forming technology manages frequency, voltage, and power-sharing across multiple sources. It’s a showcase of how smart control can enable reliable, sustainable power in remote environments.
Anything else you’d like to share as a takeaway?
Grid-forming is no longer experimental – it’s here and working. We’ve deployed it across multiple continents, including challenging environments. The industry is moving toward smarter, more stable systems, and grid-forming technologies are a critical part of that transition. We welcome collaboration with regulators, developers, operators and academia to keep advancing this technology.
