What Is Reactive Power and Why Does It Increase Your Electricity Bill?

Many facility managers open a monthly electricity bill and find charges they cannot easily explain. Alongside the kilowatt-hours consumed, some tariffs also reflect how efficiently that electricity was used. Reactive power is one of the reasons, and it is often misunderstood.

This article explains what reactive power is, why it can raise your electricity bill, how facilities commonly manage it, and where an energy saving device fits into the picture. It is written for facility managers, engineers and operators who want a clear, practical view without heavy theory.

What Is Reactive Power?

Electrical systems carry three related quantities. Active power, measured in kilowatts (kW), is the energy that does useful work: turning a motor, lighting a room, running a server. Reactive power, measured in kilovolt-amperes reactive (kVAR), moves back and forth between the source and equipment such as motors and transformers to build the magnetic fields those devices need. It does no useful work itself, but the system must still carry it.

Apparent power, measured in kilovolt-amperes (kVA), is the combination of the two. A familiar way to picture it is a glass of beer. The liquid is the active power you actually want. The foam is reactive power: it takes up room in the glass without giving you more to drink. The more foam there is, the larger the glass must be to deliver the same amount of beer.

The ratio between active and apparent power is called the power factor. A power factor close to one means most of the current is doing useful work. A lower power factor means more current is flowing than the useful load requires.

Why Does Reactive Power Raise Your Electricity Bill?

Higher current has real consequences inside a building. Cables, switchgear and transformers must be sized for the total current, not only the useful portion, so a facility with a poor power factor places more load on its own distribution equipment. That extra current produces additional heat in conductors and panels, which wastes energy and can shorten equipment life.

Utilities see the same effect on their side. Many commercial and industrial tariffs include a power factor adjustment or a demand charge based on apparent power, so a facility that draws a lot of reactive power can be billed more than its useful consumption alone would suggest. The exact rules differ by country, utility and contract, so the first step is always to read your own tariff.

Not every customer is exposed to this. Residential users and many small businesses are generally not eligible for reactive power compensation benefits under their tariffs. For them, the useful target is the active power (kW) they actually pay for, and the wiring-level effects of poor power factor remain the main concern.

How Do Facilities Usually Manage Reactive Power?

The traditional answer is power factor correction. Capacitor banks are installed at the main panel or near large loads to supply reactive power locally, so less of it has to travel from the grid. Done well, this brings the power factor closer to one. It requires sizing to the actual load and regular checking, because capacitors age and loads change over time.

Other measures address the loads themselves: right-sizing motors, using variable speed drives on pumps and fans, and avoiding lightly loaded motors that run at a low power factor. A power quality survey is the best way to see which measure matters most at a given site, because the mix of loads differs from one building or plant to the next.

Where Does an Energy Saving Device Fit?

Reducing reactive power and reducing active power are different goals. A capacitor bank compensates kVAR. FORCE ESD, the Energy Saving Device by ENPOSS, takes a different approach. It is designed to improve the conductivity of the current flowing through existing wiring, with the aim of reducing the active power (kW) a facility draws. You can read how this works on the principle of the product page. Because the goals differ, FORCE ESD should be evaluated as a separate measure from power factor correction, not as a replacement for it.

ENPOSS documents a 5 to 15 percent reduction in power usage for FORCE ESD installations. Results vary by site conditions and are not guaranteed, which is why a site assessment and a measured baseline matter more than any headline figure.

FORCE ESD uses a no-circuit design. It connects in parallel on the secondary side of the main breaker, within one meter of the electrical panel, and does not modify the existing circuit. A qualified electrician carries out the installation, which requires briefly switching off the main power, so the facility and the electrician should plan for a short outage.

Next Steps for Your Facility

Start with your own data. Review the last several bills for power factor adjustments or demand charges, ask your utility how reactive power is treated in your contract, and consider a power quality survey at the main panel. That gives you a baseline for any measure you evaluate, whether capacitor banks, drive upgrades or an energy saving device.

To go deeper, read What Is an Energy Saving Device?, learn how industrial energy saving devices work in a factory power system, or browse the FORCE ESD FAQ.

Contact our team at enposs.com to discuss your site conditions and whether FORCE ESD is a fit for your electrical system.