Global Energy Resources, Conversion, and Reserves

Energy resources: renewable and non-renewable

Energy resources are classified into renewable and non-renewable.

Renewable resources

Renewable resources include solar, wind, geothermal, hydropower, biomass, and wave and tidal energy. They regenerate naturally and have a reduced environmental impact.

Non-renewable resources

Non-renewable resources include fossil fuels (hard coal, lignite, peat, petroleum, natural gas and oil shales) and nuclear fuels (uranium, thorium and plutonium), as well as fusion fuels (deuterium, tritium and lithium), whose resources are much larger than those of fossil fuels.

Forms of energy and conversion

Energy can appear in mechanical, electrical, thermal, chemical, solar or nuclear form, and it can be converted from one form to another. A typical example is the transformation of the chemical energy of coal into heat, then into mechanical energy and finally into electrical energy. In any conversion process, losses occur, so energy engineering seeks technologies that minimize these losses and reduce environmental impact.

Resources, reserves and units

To evaluate resources, a distinction is made between geological resources (the total existing amount) and reserves (the amount that can be extracted with current technology).

The most commonly used units of measurement are tcu for solid fuels (tonne of conventional fuel, 7000 kcal/kg), toe for liquids (tonne of oil equivalent), and normal cubic meters for gaseous fuels.

Examples of resources and national context

Coal is one of the most abundant resources in the world, and Poland has large reserves of hard coal and lignite. Natural gas is also very abundant on a global scale, and Poland has limited but exploitable reserves. Nuclear energy is based on uranium, thorium and plutonium, which have large global reserves; in the case of fusion, deuterium and lithium are available in enormous quantities.

Renewables: current use and potential

Among renewables, hydropower from rivers is one of the most widely used, although there is also great potential in wave and tidal energy, which is difficult to exploit for technological reasons. Solar energy reaches the Earth with an intensity of approximately 1367 W/m² and can be used through thermal collectors or photovoltaic panels.

Biomass originates from agricultural residues, forest waste, organic waste and energy crops generated through photosynthesis, a process with low efficiency (around 5%). Geothermal energy comes from heat inside the Earth; in Poland, there is some potential, although temperatures are relatively low. Wind energy depends on wind speed and is converted into mechanical and then electrical energy using wind turbines.

Consumption trends and depletion factors

In global energy consumption, fossil fuels still dominate, although their share decreases over time while modern renewable energies such as solar, wind and advanced biomass increase. In Poland, coal use has been gradually decreasing, while oil and natural gas consumption has increased.

The depletion rate of resources depends on energy consumption, extraction technology, per-capita use and population growth, which makes it possible to estimate how many years current resources will continue to be available.