A Resilient Grid for a Renewable Future:
How Grid Forming (GFM) Inverter Supports the Next Generation of Power Supply

2025-05-21

Sustainability Editorial Sustainable Development Carbon Neutrality Circular Economy

Toward Net Zero by 2050

Achieving carbon neutrality is no longer a goal for individual countries—it is a global imperative. Renewable energy (RE), such as solar and wind, is expected to play a key role in the transition to a decarbonized society, and its adoption is rapidly accelerating worldwide.

However, we now face a paradox: the cleaner our electricity becomes, the more unstable its supply can be.

In Japan, RE currently accounts for around 20% of total electricity generation, but this figure is expected to rise to just under 40% by 2030 and exceed 50% by 2050. As RE continues to expand, two major challenges are becoming increasingly apparent.

First, RE sources such as solar and wind are highly dependent on weather and time of day, making their output inherently unstable. Ensuring the stability of the power system requires various adjustments to balance supply and demand.

Second, as RE increases, grid resilience—the ability of the power network to withstand and recover from disruptions—tends to decline. If a major power plant such as a thermal or nuclear facility fails due to accident, RE sources alone lack the inertia needed to stabilize frequency during sudden imbalances. This increases the risk of large-scale blackouts.

In this way, the more renewable electricity we introduce, the more urgent the question becomes: how do we ensure its stable delivery?

Grid resilience is emerging as a critical keyword for the future of renewable power.

GFM Inverter: A Technological Answer to Grid Resilience

Addressing the issue of grid resilience head-on is the Grid Forming (GFM) Inverter —a next-generation power conditioning technology gaining increasing attention. GFM Inverter is an inverter powered by renewable energy sources such as solar power or storage batteries. It can simulate the inertia typically provided by traditional thermal power generators.

What makes GFM Inverter especially noteworthy is its ability to act as part of the power grid itself. While traditional RE sources can only connect to an existing grid, GFM Inverter can autonomously “form a grid” and operate in coordination with other distributed energy resources.

Conventional power systems have relied on centralized models in which large-scale power plants provide voltage and frequency control for the entire grid. However, with the rise of RE and the retirement of aging thermal plants, this structure is becoming increasingly difficult to maintain. GFM Inverter’s ability to autonomously form a grid represents a major advancement—overcoming the limitations of traditional centralized models.

In times of disaster or emergency, GFM Inverter-based microgrids can continue supplying power autonomously at the local or facility level.

A Practical Implementation at Narashino Works

Hitachi Industrial Equipment Systems (HIES) has taken the lead in implementing GFM Inverter at its Narashino Works in Chiba, Japan.

Since its launch in April 2025, the implemented system has drawn attention as one of the world’s pioneering model cases for sustainable and resilient power supply.

The site features 81.9 kW of solar generation and a DC power network. Electricity generated from solar panels is stabilized by three parallel GFM Inverters and delivered as AC power to in-house equipment, including water pumps (HIES-made) and emergency broadcast systems. Even when solar output fluctuates, the GFM Inverter autonomously regulates frequency and maintains an AC microgrid within the facility.

The system also includes DC distribution to reduce energy conversion loss. Excess solar power is stored in batteries or supplied to the commercial grid via an HIES power conditioner, ensuring full energy utilization.

As a result, the site is expected to reduce CO₂ emissions by 39.2 tons annually.

Such an integrated, real-world system—combining RE stability, disaster resilience, and autonomous microgrid functionality—is rare even on a global scale.

Narashino serves as a practical reference for future decentralized energy societies.

This system was selected for a carbon reduction subsidy from Japan’s Ministry of the Environment subsidy program, recognizing its advanced structure and high societal relevance.

Experience the Future of Energy—From the Ground Up

Supporting the future of renewable energy requires more than simply increasing generation capacity.
The real question is: how do we deliver it in a stable, sustainable way?

HIES' Grid Forming Inverter offers one answer to this pressing challenge.

To see the system in action and learn more about the initiative at Narashino Works, watch the video below.

NOTE: This video is narrated in Japanese. To view English subtitles, please click thesettings (⚙️) icon on the YouTube player, select “Subtitles/CC,” and choose “English.”