Wood briquettes are made of dry, untreated wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

 chips (e.g. wood shavings). They are pressed with high pressure without any binder

Binder (material)

-See also:*Adhesive or Glue*Cement*Paint...

. By compacting the wood with this high pressure, it turns into a fuel like brown coal.

Advantages

The advantages of the wood briquettes are that they have a lower ash

Wood ash

Wood ash is the residue powder left after the combustion of wood. Main producers of wood ash are wood industries and power plants.-Composition:...

  and sulfur

Sulfur

Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

 content, compared to the fossil fuel

Fossil fuel

Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...

s. The carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 (CO₂) balance is even, because wood briquettes release just as much CO₂ to the atmosphere as the tree

Tree

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

 absorbs through growth by photosynthesis

Photosynthesis

Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...

. In addition, briquettes have substantially higher BTU value per cubic foot due to their density which means less storage space and more heat released per lb.

Energy content

The low moisture content of about 10% leads to an energy

Energy

In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...

content of around 5,0 kWh per kg, depending on the type of wood. Green firelogs have a water content of around 50% with 2,5 kWh/kg energy content.