Reactive Power

Reactive power refers to the portion of electricity in the grid that establishes magnetic fields in network equipment (such as cables, motors, and transformers), without performing any useful work.

What is reactive power in the electricity grid?

To better understand reactive power, it’s essential to delve into the workings of alternating current (AC).

In the Netherlands, we use AC, where the current direction changes 50 times per second—a frequency of 50 Hz. Both voltage (Volts) and current (Amperes) follow a sinusoidal waveform.

Ideally, voltage and current are perfectly in phase: their sine waves align, with voltage peaks coinciding with current peaks, resulting in continuous maximum power delivery. This relationship is expressed as:

P = U x I (Power = Voltage × Current)

However, many devices—such as electric motors, transformers, or inverters—contain coils (inductance) or capacitors (capacitance). These components cause the current waveform to lag or lead the voltage waveform, introducing a phase shift between voltage and current.

With inductive loads (like motors or transformers), the current lags behind the voltage.
With capacitive loads (such as certain electronic equipment or capacitor banks), the current leads the voltage.

This phase shift results in the generation of reactive power.

Reduced usable power

A greater phase shift (i.e., increased reactive power) leads to less efficient use of the grid:

More current is required to deliver the same amount of useful energy.
Lines and transformers reach capacity limits sooner.
Voltage quality may deteriorate.
Additional losses occur within the grid.

Therefore, it’s crucial to improve the power factor by minimizing or compensating for reactive power.

Reactive power also causes voltage issues

Maintaining a consistent voltage (e.g., 230 V or 10,000 V) in the electricity grid is vital, as equipment is designed to operate within specific voltage ranges. Significant deviations—whether too high or too low—can lead to:

Malfunctioning equipment
Increased wear and tear
In severe cases: failures or damage

Reactive power contributes to these voltage problems because it affects the total current flowing through the grid, influencing voltage levels and stability.

An Example

Imagine a neighborhood with a high level of solar energy generation. During the day, inverters in the area produce capacitive reactive power, while local demand is low. As a result:

A large amount of (reactive) current flows toward the medium-voltage grid
Voltage levels on transformers are pushed upward
Voltage issues may arise for other customers in the area

Conversely, if a factory draws a large amount of inductive reactive power during peak hours, the voltage may drop too far — increasing the risk of disruptions.

Reducing Reactive Power

Large-scale energy users can actively contribute to managing reactive power. With the right settings and smart control, it’s possible to:

Reduce reactive power (generate less of it)
Compensate for it (supply negative reactive power when the grid demands positive, or vice versa)

Do you have:

Large electric motors or pumps?
Industrial processes with high inductive loads?
Heat pumps, compressors, or other variable-power equipment?
Energy storage systems or inverters (e.g. for solar energy)?

Then there’s a good chance you have controllable capacity that can help mitigate reactive power issues in the grid.

In Q2 of 2025, GOPACS will launch a pilot to reduce reactive power. Interested in participating? Keep an eye on our website and LinkedIn.

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