Transmission energy losses – where do they come from and how can they be reduced?

What are transmission energy losses?

Transmission losses are the difference between the amount of electrical energy introduced into the transmission network and the amount of energy taken from it within a given period. They are included in the energy balance of the power system and constitute a natural consequence of transporting energy through network infrastructure. Some of the energy is lost primarily in the form of heat generated in conductors and electrical equipment. The level of losses is one of the parameters that makes it possible to assess the technical efficiency of the network and the way it is operated.

Transmission losses should be distinguished from distribution losses. The former occur in the highest- and high-voltage networks used to transport large amounts of energy over considerable distances. Distribution losses, on the other hand, occur when energy is delivered to consumers through medium- and low-voltage networks. Due to lower voltage levels, a large number of consumers, and the extensive structure of the network, the nature of distribution losses may be different.

Network operation analyses also use a division into technical and non-technical losses. Technical losses result from the laws of physics and the properties of conductors, transformers, and other equipment. Non-technical losses are related, among other things, to measurement errors, incorrect energy billing, or illegal energy consumption. Distinguishing these categories makes it possible to properly identify the sources of the problem and select measures aimed at improving the efficiency of network operation.

Where do transmission losses come from?

The primary cause of technical energy losses is the electrical resistance of conductors. The flow of current causes heat to be released, in accordance with Joule’s law. The amount of losses generated in this way depends, among other things, on the current intensity, the resistance of the conductor, its length, cross-section, and operating temperature. Particularly important is the relationship between losses and the square of the current intensity. An increase in line load can therefore lead to an increase in the amount of energy lost during transmission. The level of losses is also affected by the length of the line and the voltage used to transport energy. The greater the distance, the greater the resistance of the conductors and the associated losses. Energy transmission over long distances is therefore carried out using very high voltages. For a given power, increasing the voltage makes it possible to reduce the current intensity and thus limit heat losses in the conductors.

Energy is also lost in transformers and other electrical equipment. Transformers experience, among other things, losses in the windings and magnetic core. Their magnitude depends on the design of the device, its technical condition, and the level of load. Therefore, the proper selection of equipment for operating conditions, regular diagnostics, and replacement of worn infrastructure components are important. Transmission efficiency is also affected by reactive power flows and the parameters of electrical power quality. Excessive reactive power flow increases the current intensity in lines, even though this energy is not directly converted into useful work for consumers. The result is additional heat losses and greater infrastructure loading. Similar consequences can be caused by inappropriate voltage levels, load asymmetry, or the presence of higher harmonics.

How are energy losses measured and analyzed?

The basis for assessing losses is energy balancing. It involves comparing the amount of energy introduced into a specific area of the network with the amount of energy that flowed out of it or was taken from it. The analysis may cover the entire transmission network, selected areas, or individual lines, transformers, and substations. The more detailed the measurements, the easier it is to identify locations where increased losses occur.

Operators use measurement systems and infrastructure monitoring systems for this purpose. Data on power flows, voltage, current intensity, equipment temperature, or load level make it possible to observe the condition of the network and detect deviations from typical operating parameters. Regular comparison of measurement data also makes it possible to identify changes that may indicate deterioration of the technical condition of equipment.

An important element of the analysis is power flow calculations. They make it possible to determine how energy flows through individual components of the system and in which parts of the network the greatest loads occur. On this basis, the operator can assess the effects of changes in the network configuration, the shutdown of a particular line, or the connection of new energy sources. Operational data also provide the basis for planning repairs, modernization, and investments in infrastructure development.

How can transmission losses be reduced?

1. One of the basic ways of reducing losses is infrastructure modernization. Replacing conductors with solutions featuring appropriate technical parameters, using more efficient transformers, and improving the condition of connections and equipment make it possible to reduce the amount of energy lost during transmission. Investment decisions should be preceded by an analysis of operational data so that resources are directed primarily to those parts of the network where modernization will bring the greatest benefits.
2. The appropriate transmission voltage level is also important. Increasing the voltage makes it possible to transport a given amount of power at a lower current intensity. This reduces losses resulting from the heating of conductors. However, this solution requires appropriate infrastructure, compliance with safety requirements, and consideration of the costs of constructing and operating the equipment.
3. Power flow optimization and reactive power compensation are also important for reducing losses. Appropriate control of network operation makes it possible to limit line overloads and direct energy flows along routes that ensure lower losses. Devices used for reactive power compensation reduce unnecessary current flows and improve the utilization of available transmission capacities.
4. Digital monitoring and analytics systems are becoming increasingly important. Solutions such as Nomad NX support the analysis of data concerning the operation of power infrastructure, facilitating the assessment of its condition and identification of areas requiring optimization. Continuous access to data makes it possible to detect irregularities more quickly and supports decision-making concerning equipment maintenance and investment planning. Reducing losses therefore requires a combination of infrastructure modernization, appropriate management of energy flows, and systematic data analysis.

Transmission energy losses are unavoidable, but their level can be effectively reduced through infrastructure modernization, energy flow optimization, and proper network management. Modern measurement systems and analytical tools make it possible to identify areas generating excessive losses more quickly and appropriately plan technical measures. Reducing losses improves energy efficiency, lowers system operating costs, and increases the reliability of energy supplies.