8.1 Introduction: From traditional energy supply to intelligent infrastructure
Energy technology is one of the oldest application areas of electrical engineering. Since widespread electrification in the late 19th century, energy supply has continuously evolved. In the 20th and 21st centuries, the efficient control and conversion of electrical energy – power electronics – has increasingly joined the pure generation of energy.
While traditional power engineering relied primarily on generators, transformers, and power grids, power electronics enables precise control of voltages, currents, and frequencies. This has made it a key component of modern energy systems.
8.2 Fundamentals of electrical energy conversion
Electrical energy is generated in power plants by converting mechanical energy. Turbines – driven by steam, water, or wind – drive generators that produce electrical voltage according to the principle of induction.
Important energy sources:
- Hydropower
- Coal and gas-fired power plants
- Nuclear energy
- Wind energy
- Photovoltaics
The electrical energy is then transported via high-voltage networks and distributed to lower voltages by transformers.
8.3 Development of high-voltage transmission
To minimize transmission losses, electrical energy is transported at high voltages. The development of:
- Insulation materials
- Overhead line technology
- High-voltage direct current (HVDC) transmission
- Gas-insulated switchgear
It enabled stable long-distance transmission over hundreds and thousands of kilometers.
Grid stability depends on frequency stability, phase angle, and load distribution.
8.4 Development of power electronics
The development of semiconductor devices made it possible to electronically switch and control high power levels. Power semiconductors such as:
- Thyristors
- MOSFETs
- IGBTs
- Silicon carbide and gallium nitride transistors
enable efficient conversion of alternating current to direct current and vice versa.
Power electronics are used in:
- Power converters
- Inverters
- Engine control units
- Charging infrastructure
- Grid stabilizers
It combines energy technology with modern semiconductor physics.
8.5 Regulation and grid stability
Electrical grids must be kept in constant balance. Supply and demand must match exactly, as electrical energy can only be stored to a limited extent.
Key concepts:
- Primary, secondary and tertiary regulation
- Frequency control (50/60 Hz)
- Load management
- Reactive power compensation
Power electronic systems contribute significantly to grid stabilization.
8.6 The energy transition and decentralized generation
In the 21st century, the energy transition is fundamentally changing the structure of the electricity supply. Instead of fewer large, centralized power plants, many decentralized producers are emerging.
- Photovoltaic systems
- Wind farms
- Combined heat and power plants
- Battery storage
This development requires intelligent control systems, so-called smart grids.
Smart grids integrate digital communication, sensors and automation technology into the power grid.
8.7 Energy storage technologies
Since renewable energies are weather-dependent, energy storage is gaining in importance.
Storage types:
- Pumped storage power plants
- Lithium-ion batteries
- Redox flow batteries
- Hydrogen (Power- to -Gas)
- Supercapacitors
Power electronic interfaces enable the integration of these storage devices into the power grid.
8.8 Electromobility
Electromobility represents an important application area for modern power electronics. Electric vehicles require:
- High-performance batteries
- inverter
- Engine control units
- chargers
The integration of vehicles into the power grid (vehicle -to - grid ) opens up new possibilities for load control.
Electromobility combines energy technology, electronics and transport systems.
8.9 Sustainability and resource efficiency
Modern energy technology faces ecological challenges. Increasing efficiency and reducing CO₂ emissions are key objectives.
Electrical engineering innovations contribute through:
- Energy-efficient drives
- Performance-optimized network structures
- Low-loss semiconductors
- Intelligent load control
Sustainability is increasingly becoming an integral part of technological development.
8.10 Future prospects
Future developments include:
- Superconducting lines
- High-voltage direct current networks on a continental scale
- Smart distribution networks with real-time monitoring
- AI-powered network optimization
- Sector coupling (electricity, heat, mobility)
Energy technology is evolving from a static supply system to a dynamic, digitized energy ecosystem.
8.11 Summary
Chapter 8 highlights the central role of energy technology and power electronics in modern electrical engineering.
Key developments:
- High-voltage transmission
- Power semiconductors
- Smart Grids
- Energy storage
- Electromobility
The transformation of the energy infrastructure is one of the greatest technical challenges of the 21st century and significantly shapes the future development of electrical engineering.