First, several important things about energy.
Energy is the capacity of a physical system to do work.
Universal symbol for energy is the uppercase letter E, and standard unit in is joule, symbolized by J.
Energy has its primary sources and forms.
Basic sources of energy found in nature are:
- Energy from the Sun
- Energy from the Earth
- Energy of gravity
Basic forms of energy are:
1. Gathered energy (known as the accumulated energy) which include:
- Energy of position (potential)
- Energy of movement (kinetic)
- Internal energy
2. Transformed energy – energy that passes from one to another form or energy. It is the energy which occurs when the accumulated energy is crossing from one body to another. Transforming the energy passes through several forms (which are interrelated and short), which defined as:
- Primary (natural) energy – the energy that comes directly from primary sources of energy,
- Secondary energy – primary energy stepped into another form through the technical process,
- The final energy – energy that comes to the user (eg electricity)
- Useful (applied) energy – the energy which the user uses (mechanical, thermal, light, chemical).
Natural (primary) forms of energy, based on its durability and opportunities for their extraction can be classified as:
1. Non-renewable forms of energy
- fossil fuels (coal, oil, natural gas)
- nuclear fuel
2. Renewable forms of energy
- energy of water power (energy of water flows, sea currents and waves, tides)
- energy from biomass (biogas, including both wood and organic waste)
- energy from solar radiation
- wind energy
- geothermal energy
It is particularly important to know that every transformation of energy occur losses. Therefore most important task of the energetich must be energy economy in the process of transformation of energy from primary to useful form. Our task as users of energy must be careful, smart and economical use of energy.