Grid, microgrid and island frequency stabilization

Sub-10 millisecond response to frequency dips and spikes, millions of cycles without degradation. Built for FCR-N and Fast Frequency Response.

What this looks like in practice

Power grids run at a fixed frequency, 50 Hz in Europe. When supply and demand fall out of balance, the frequency dips or spikes, and the grid has seconds to correct it before things start tripping offline. Renewables make this harder: solar and wind drive sharper, faster swings than the grid was built for.

A flywheel sits on the grid spinning. Within 10 milliseconds of a dip, it releases power into the network. Within 10 milliseconds of a spike, it absorbs power back. It also smooths the power peaks when they come. All of this without the cycle damage a battery would take from doing the same job thousands of times a day.

A frequency event on the grid

A 1.4 MW generation loss, simulated. Without a fast response, the grid drops past the trip threshold inside one second.

Normal operating range (49.8 to 50.2 Hz) 50.5 50.2 50.0 49.8 49.5 49.0 0 1 2 5 10 15+ Time after generation loss (seconds) Frequency (Hz) Trip threshold (49.0 Hz) Flywheel acts here < 10 ms Generator response (~5 s) Trip threshold reached
Normal operating range
With flywheel (stays inside the band)
Without flywheel (drops to the trip threshold)
Trip threshold
Curve shapes are typical for a sudden generation loss on a small-to-medium grid with limited inertia. Exact recovery shape depends on system inertia, fault size, and reserve response.

Where this fits

Frequency stabilization shows up at three scales, and the same flywheel platform serves all three with different sizing and connection topology.

Grid scale

Transmission and distribution

FCR-N, Fast Frequency Response, synthetic inertia, and grid-forming services delivered into wholesale ancillary markets, including the Nordic FCR-N market that wears batteries out fastest.

Microgrid scale

Campus, industrial, and military

Stabilising frequency on a closed network where one large load change or one renewable ramp can swing the whole system. A flywheel slows the rate of change of frequency (ROCOF) and limits the frequency nadir during faults, holding the network inside its operating envelope.

Island scale

Weak and isolated grids

On islands and remote networks with limited inertia, the frequency nadir is deeper and ROCOF is steeper after any disturbance. A flywheel adds synthetic inertia that flattens both, without the chemistry constraints of battery storage on a hard-to-service site.

Validated by simulation

An independent grid simulation study of two small Azores islands modelled a Teraloop flywheel running synthetic inertia and grid-forming control. The flywheel reduced the rate of change of frequency and lifted the frequency nadir in every worst-case scenario tested.

−85%
ROCOF reduction on a small island grid worst case
+1.6 Hz
Frequency Nadir improvement during a generator trip
−65%
ROCOF reduction on a larger island worst case (−20 to −7 Hz/s)
250 kW
Flywheel modelled, PowerLoop 250 platform

Source: Independent grid simulation study, Corvo and Flores Islands, Azores, March 2026. Modelled in DIgSILENT PowerFactory with a Grid-Forming inverter and virtual inertia time constants of 15 s and 30 s.

Why a flywheel here

Faster than the grid period

Sub-10 millisecond response is faster than the 20 millisecond grid cycle, which is the threshold for supporting every power quality service.

Made for high-cycle duty

Millions of cycles with no capacity fade. FCR-N alone cycles a battery thousands of times a year, and a flywheel does that job without degradation.

No flammable chemistry

Indoor, outdoor, in dust or in heat, on islands without a fire brigade in reach. The flywheel does not need any of it.

Tell us about your grid.

Share your inertia situation, the market you are bidding into, and your renewable mix. Our engineering team will come back with a sizing and a starting estimate.