How to effectively manage reactive energy?

There are two main types of reactive energy:

• Inductive reactive power (inductance – L) – generated in devices containing inductive components, such as motors, transformers, chokes, and induction furnaces. It is characterized by a phase shift in which the current "lags" the voltage.
• Capacitive reactive power (capacitance – C) – generated by electronic devices and installations with high electrical capacity, such as inverters, cables, UPSs, and newer LED lighting. In this case, the current "outpaces" the voltage.

Excessive inductive and capacitive reactive power both incur additional charges under the tariffs of distribution network operators (DSOs), increase transmission losses, and can sometimes lead to grid overload.

We wrote about the exact nature of reactive power here: Reactive energy - what is it and how to solve the problem with its consumption 

How to effectively manage reactive energy in an industrial plant?

Modern plants, with their changing load profiles and the intensive use of various devices generating both types of reactive power, require tailored solutions to compensate for excess reactive power as effectively as possible.

Common errors in reactive energy management include:

• overcompensation – incorrect power factor settings of the installed capacitor/reactor bank can lead to excess capacitive/inductive power and subsequent charges,
• failure to locate the source of the problem – installing capacitors in one location within the plant, while the source of reactive power is located elsewhere,
• lack of automation – manual compensation control under varying load conditions results in undercompensation or overcompensation,
• failure to modernize the compensation system after plant modernization, e.g., by adding modern motors, LEDs, or inverters,
• lack of measurement – managing reactive energy without prior data analysis can lead to costly and ineffective solutions.

Adjusting compensation to the load profile

In industrial plants where the load varies over time, automatic compensation systems with step or continuous control are most effective. These systems include capacitors, reactors, and controllers with automatic compensation power selection in real time. This allows for maintaining tgφ at a level consistent with DSO requirements, without overcompensation.

tgφ is a factor used by grid operators to bill for reactive energy consumption. Its level typically cannot exceed 0.4 (sometimes this value is more restrictive) – this means that consumption of more than 40 kvarh of reactive energy for every 100 kWh of active energy consumed results in an additional fee from the operator.

There are situations in which traditional solutions for reactive power compensation, which involve switching on individual capacitor/reactor stages, may not be sufficient. In such cases, active SVG (Static Var Generator) compensators are used – electronic systems that dynamically compensate for both inductive and capacitive power, often also for higher harmonics.

Local compensation applications

In large plants, or where there are large, individual sources of reactive power (e.g., motors with a power output >200 kW), it is worth considering local compensation, i.e., directly at the load. This reduces reactive power flow in supply lines, reduces transmission losses, and improves local voltage levels.

Monitoring and diagnostic systems

Effective reactive energy management requires reliable data. This data is obtained using:

• network parameter analyzers – allowing real-time monitoring of active and reactive power, harmonics, overvoltages, voltage unbalance, and other power quality parameters,
• disturbance recorders and long-term data logging – useful for analyzing load variability and assessing compensation effectiveness or selecting appropriate compensation,
• SCADA or EMS systems – enabling full visualization, historical data analysis, and remote control of compensation devices.

Such solutions enable quick response to parameter exceedances and maintain high energy efficiency without the need for constant manual monitoring.

What are the risks for a company that fails to manage reactive energy?

Failure to take action on reactive energy management doesn't just result in higher electricity bills. There are a number of risks that can negatively impact the operation of the entire facility:

• additional costs – fees for excessive reactive energy consumption, often exceeding several thousand złoty per month,
• risk of internal grid overload – especially in older installations,
• voltage and power quality problems – resulting in flickering lighting, failure of inverters, and other sensitive power electronic devices,
• shortened equipment lifespan – overheating of transformers and lines, as well as excessive operation of cooling devices,
• difficulties in meeting the requirements of the ISO 50001 standard – regarding monitoring and improving energy efficiency,

In extreme cases, excess reactive energy can lead to production downtime or the need for costly modernization of the internal power grid.

Reactive energy as part of an energy strategy

In a modern approach to energy efficiency, reactive energy management is not a one-time activity, but rather part of a systemic approach. It's worth considering during energy audits and installation inspections, when planning investments in new equipment, or as part of a company's energy policy aligned with ESG and decarbonization strategies.

Integrating reactive energy management systems with comprehensive EMS (Energy Management System) platforms enables ongoing monitoring and reporting of efficiency indicators, translating into sustainable savings and improved plant reliability. Reactive energy is not only a matter of costs but also of reliability, power quality, and equipment durability. Failure to act can have financial and operational consequences. Therefore, reactive energy management should be based on precise measurements, appropriately selected technologies, and continuous monitoring.