Energy supply and efficiencies – basic principles
How it works
Energy supply includes the generation, conversion, storage and use of energy in various forms (e.g. electrical, chemical, thermal energy). Efficiency is the ratio of usable energy to supplied energy and describes how efficiently a system converts energy. In real processes, part of the supplied energy is converted into other, often less usable forms such as heat, sound or light. Typical energy sources are fossil fuels, renewable energy and nuclear energy. Energy conversions take place in power plants, engines and household appliances. Knowledge of efficiency is important in order to identify energy losses and compare technologies.
The efficiency (η) is calculated as the quotient of delivered (usable) energy and supplied energy: η = (delivered energy) / (supplied energy). It is often given in percent.
An example
An electric motor receives 1000 joules of electrical energy and performs 700 joules of mechanical work. How high is the efficiency?
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50 Exercises
To the learning unit →Own explanation and own practice exercises by AmyMath. Subject reference framework: Physics. The topic assignment may vary by federal state.