Grid stability |
Building future-ready grids: why real-time stability measurement matters
Without real-time visibility, operators face rising costs and renewable curtailment. Measurement is the key to unlocking capacity safely
Colin Gault Chief Product Officer, Reactive Technologies
Power systems are entering a new era shaped by rapid electrification, net-zero targets, and the rise of inverter-based resources. These changes bring extraordinary opportunities, but also new challenges for grid stability. In the past, large industrial facilities used synchronous motors that naturally contributed inertia to the grid. Today, many very large loads, often data centres, are dominated by power-electronic interfaces and typically provide no rotational inertia at all. As a result, operators face inertia and system- strength conditions that fluctuate more quickly and with far less predictability. While they try to avoid running systems near stability limits, the pressure to integrate more renewables and use the network more efficiently is pushing the industry towards operating closer to physical limits, provided they have real-time visibility and measurement to do so safely.
Across regions, these pressures are visible in operational costs and incident trends. Great Britain’s balancing costs reached more than £4 billion in 2022 and are forecast to rise to £8 billion by 2030. Events such as the April 2025 Iberian system collapse illustrate how quickly disturbances can spread.
Traditional stability management relied on models and heuristics developed for predictable synchronous generation. These tools remain central to planning and risk analysis. However, they are less effective in a system shaped by advanced electronic systems that adjust power flows almost instantly. Distributed resources
change continuously, adding complexity. Operators need to understand the system’s true dynamic state at any moment. Without that insight, they often resort to increasing reserve procurement or curtailing renewable generation to maintain security.
Reactive Technologies addresses this challenge head-on. Our GridMetrix®
platform
actively measures system inertia in real time by introducing small, precisely designed energy pulses into the network (modulation) and capturing the grid’s frequency response with high-fidelity sensors. These measurements provide clarity during periods of low inertia and high renewable output, conditions where models carry the greatest uncertainty. For operators, this means running closer to true limits safely and keeping more renewable generation online without compromising reliability.
An integrated view of system stability
Over time, GridMetrix® has evolved into a
comprehensive stability measurement system, offering visibility of three linked pillars of dynamic operability: inertia, system strength, and oscillations, in one integrated view. By viewing these parameters together, operators gain a complete picture of grid stability, enabling faster and more confident decisions.
Reactive’s grid-edge measurement devices measure the voltage waveform 48 000 times per second with full GPS time alignment. This
precision gives operators confidence to act quickly. It also enables rapid rollout in areas of concern. While primarily designed for inertia measurement, the measurement devices also capture oscillations, offering operators a multi- purpose tool for dynamic stability monitoring. Analytical tools present these measurements in both live dashboards and post event analysis, giving operators the data needed for immediate response and longer-term planning. Real-time grid measurement does not replace planning models. Instead, it helps calibrate them and enhances model accuracy by anchoring them in measured system behaviour. As inverter-based resources grow, controller settings and plant performance can deviate from assumed values. Measured data reveals where these deviations occur and helps engineers adjust planning studies, dynamic models, and security limits accordingly. For operators, this means fewer conservative margins and more renewable generation online; without compromising reliability.
The combination of active measurement and traditional monitoring tools, eg, PMU-based passive observation, produces a more robust understanding of stability than either approach alone.
Real, measurable global impact From Great Britain to Japan, leading operators are adopting Reactive’s solutions to unlock renewable hosting capacity and cut carbon emissions.
The National Energy System Operator (NESO) in the UK was the first to deploy real-time inertia measurement at scale, enabling up to 30% more renewable hosting capacity, and supporting an estimated reduction of 18 million tons of carbon dioxide each year. The project is expected to deliver $92.5 million in operational savings over 5 years. It has also been able to lower the minimum inertia required at national level, which has a significant cost benefit.
How GridMetrix® measures grid stability. Image: Reactive Technologies 18 | November/December 2025|
www.modernpowersystems.com
In North America, real time measurement supported a NYSERDA Future Grid Challenge project aimed at meeting New York State’s Climate Act targets. A major East Coast utility is deploying the technology for system strength measurement, with early results expected in 2026. In Japan, HEPCO (Hokkaido Electric Power Company) is using real time oscillation monitoring
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