Fuels (heating)

Fuels are products in liquid, solid or gaseous form that are used to generate heat and electricity. They can consist of one or more chemical elements and are divided into different categories, including fossil fuels and renewable fuels.

Definition
A fuel is a product that is used to generate energy, with a focus on heat and electricity production. Fuels are also known as primary energy carriers when they are used to generate electricity. They usually consist of carbon and hydrogen and can occur in both fossil and renewable form.

Background / Origin
Fuels are essential energy sources that occur in different forms and compositions. Their use to generate heat and electricity has been of great importance since the industrial revolution. In Germany, the fuel supply is heavily dependent on imports, with a large proportion of the required fuels being sourced from other countries, while domestic wood production meets part of the demand for biofuels.

Fossil fuels, such as coal, natural gas and heating oil, dominate the market, while renewable fuels are becoming increasingly important. This development is a result of growing environmental awareness and political efforts to reduce greenhouse gas emissions. Energy policy also has an impact on the taxation of fuels, which in Germany is regulated by the Energy Tax Act.

Properties
Fuels are characterized by their chemical composition and aggregate states. They can be divided into solid (e.g. wood, coal), liquid (e.g. heating oil, ethanol) and gaseous states (e.g. natural gas).

The chemical composition can contain various elements, with hydrogen and carbon being the main components. The energy content of a fuel is determined by the heating value and the calorific value, which indicate the amount of energy released during combustion. The calorific value also takes into account the heat of condensation.

Fossil fuels have different qualities and properties that influence their use. Regenerative fuels, such as biofuels, are usually more environmentally friendly and come from renewable raw materials.

Application and importance in the market
Fuels are mainly used to generate heat and electrical energy. In the mobility sector, they are used as fuels. In the heating market, liquid fuels such as heating oil and gas offer essential solutions for heating systems in households and industry.

The international fuel supply varies greatly, depending on the available raw materials and political framework conditions. The import of raw materials such as crude oil, natural gas and hard coal is particularly important in Germany, while the production of biofuels is supported by domestic wood resources.

Differentiation from similar terms
- Fuel: The term "fuel" refers specifically to fuels used for mobility, while "fuel" applies generally to heat and electricity generation.
- Heating value vs. calorific value: Heating value refers to the maximum usable amount of heat without taking condensation heat into account, while calorific value also takes this into account.

Summary
Fuels are essential products for the generation of heat and electricity and can exist in different aggregate states. Their chemical composition varies, with fossil and renewable fuels playing a central role. Energy production and market conditions are heavily dependent on imports, while taxation in Germany is regulated by law. The use of biofuels underlines the trend towards sustainability in the energy sector.