Three-phase current, also known as three-phase alternating current, is the predominant form of electrical energy transmission in power grids worldwide, including Austria. This type of electricity enables the efficient transmission of energy over long distances and supplies both industrial and private consumers with electricity. Three-phase systems consist of three phases, each of which is 120 degrees out of phase, resulting in constant and uniform power.

A major advantage of three-phase current is its ability to transmit large amounts of electrical energy with comparatively low losses. In contrast to alternating current systems with only one phase, three-phase systems allow electric motors to be operated more efficiently, which is of key importance in industrial applications. Industrial companies in Austria rely on three-phase current for the operation of machines and systems, as it can meet higher power requirements. It is also used in households, especially for power-intensive appliances such as electric cookers or heat pumps.

In the Austrian energy market, three-phase current plays a decisive role in the integration of renewable energies. Most large power plants, including hydroelectric power plants, which play a dominant role in Austria, feed the electricity they generate into the grid as three-phase current. Wind power and photovoltaic plants also generally use three-phase current to integrate the energy they generate into the grid. Three-phase current enables the stable and low-loss feed-in and distribution of the electricity generated.

Grid operators, in particular the transmission system operator Austrian Power Grid (APG), work with three-phase current to ensure security of supply in the country. The grid operator must ensure that the voltage and frequency of the three-phase current remain stable at all times, as fluctuations can jeopardise grid stability. In the event of an oversupply of renewable energy or bottlenecks, suitable measures must be taken to maintain the balance in the grid. Modern grid management systems and regulating power plants intervene to stabilise the 50 Hertz cycle of three-phase current.

In addition to the efficient transmission and distribution of electrical energy, three-phase current also offers advantages in the internationalisation of the electricity market. Austria is strongly integrated into the European electricity market and participates in cross-border electricity trading via the ENTSO-E grid. As almost all European countries rely on three-phase current, this facilitates the trade and physical exchange of electricity across national borders. Austria benefits from the synchronisation of the three-phase system, particularly in cooperation with neighbouring countries such as Switzerland and Italy, in order to trade electricity flexibly and securely within the internal market.

Another area of application for three-phase current in Austria relates to public transport. Many railway and tram networks operate their electric vehicles with three-phase current, as this ensures high efficiency and performance when supplying electric motors. Three-phase current will play a key role, particularly in the expansion of electrified railway networks, which is an important strategy for reducing CO₂ emissions.

In the future, three-phase current is also expected to play a key role in the electrification of road transport, particularly in the development of fast-charging infrastructures for electric vehicles. As the demand for powerful charging systems increases, three-phase current provides an ideal basis for minimising charging times and managing the load on the grid.

To summarise, three-phase current is the foundation of modern electricity grids in Austria and throughout Europe. Its efficiency, stability and flexibility make it indispensable for security of supply, the integration of renewable energies and cross-border electricity trading. While new technological developments such as smart grids and energy storage are gaining in importance, three-phase current will continue to support the energy infrastructure and set the course for a sustainable and stable energy future.