Biomass is all organic matter created by the growth of plants and animals. Of all renewable energy sources, the largest contribution is expected in the near future from biomass.
About 2,000 billion tons of dry biomass are produced on earth every year. About 1.2% of it is used for food, 1% for paper and 1% for fuel.
The rest, about 96%, rots or increases renewable energy supplies.
Renewable energy sources such as biogas, biodiesel, biogasoline (ethanol) can be produced from biomass, and the dry mass can be ground into small pieces of pellets, which can be burned in automated furnaces to produce heat and electricity.
A large amount of unused biomass remains in agricultural production.
Various residues in crop production, such as residues from the pruning of fruit trees, vines and olives, straw, corn, sunflower stalks, etc., are relatively easily usable forms of energy.
The production and use of biomass for energy purposes reduces the emission of harmful substances and contributes to the protection of soil and water and increase biodiversity. Biomass is a very acceptable fuel from the point of view of environmental impact because it contains very little or even no harmful substances – sulfur, heavy metals, etc., which are found in fossil fuels, and which are emitted into the air and endanger our health. and the environment. The main advantage of biomass over fossil fuels is its renewability.
The load on the atmosphere with CO2 when using biomass as a fuel is calculated to be negligible, since the amount of CO2 emitted during combustion is equal to the amount of CO2 absorbed during plant growth. Lately, it has become increasingly apparent that today’s approach to energy is unsustainable. Of all renewable energy sources, the largest contribution is expected in the near future from biomass.
Biomass, as well as its products – liquid biofuels and biogas, is not only potentially renewable, but also similar enough to fossil fuels that direct replacement is possible.
Biomass is a renewable energy source, and can generally be divided into wood, non-wood and animal waste, within which can be distinguished:
• Wood biomass
- Residues and waste from sawing, grinding, planing…
- It is often waste that burdens the business of a wood processing company
- It serves as fuel in its own boiler rooms, raw materials for products, briquettes, pellets
- It is cheaper and of better quality fuel than forest biomass
• Residues and waste from agriculture
- Straw, maize, cobs, stalks, seeds, husks…
- It is a heterogeneous biomass of different properties
- It has a low calorific value due to the high moisture content and various impurities (chlorine!)
- It is processed by pressing, baling, pelleting
- Denmark: a 450 MW power plant has been installed on grain residues!
• Animal waste and scrap
- Anaerobic fermentation (feces – all types of animals + green mass)
- Incineration (litter, carcasses – poultry farms)
- Biogas (60% methane, 35% CO2 and 5% mixture of hydrogen, nitrogen, ammonia, hydrogen sulfide, CO, oxygen and water vapor)
• Biomass from waste
- Green fraction of household waste
- Biomass from parks and gardens from urban areas
- Sludge from wastewater collectors
Solid biomass includes wood, agricultural and other organic by-products and waste.Solid biomass can be burned and thus, heat energy can be obtained from it for heating or electricity production. It can be converted into biofuels or biogas by various processes and used as such to obtain energy.
• Some ways of processing and use of biomass
- composting (for the purpose of obtaining fertilizers)
- anaerobic digestion (biomass rots for the purpose of obtaining methane and sludge used as fertilizer)
- fermentation and distillation (for the production of ethyl alcohol)
- destructive distillation (produces methyl alcohol from cellulose-rich waste)
- pyrolysis (heating of organic waste without the presence of air for the purpose of producing flammable gas and coal)
- incineration for the purpose of obtaining heat and electricity
- constuction materials
- biodegradable plastics and paper (use of cellulose fibers)
Biofuels are fuels obtained by processing biomass. In recent years, biofuel production and consumption have been growing. They are far more environmentally friendly than fossil ones, but their production is still more expensive. The most intensive production is in Brazil (from sugar cane) and in the USA (from corn). The main biofuels are bioethanol and biodiesel.
Bioethanol is an alternative to gasoline. It is produced from sugar cane, corn, barley, potatoes, sunflower, grain, wood and some other biomass. The most intensive production is in Brazil. The European Union already consumes significant amounts of bioethanol. Croatia has great potential for the production and export of bioethanol.
Biodiesel is an alternative to conventional diesel produced from fossil fuels. It is produced mostly from oilseeds (rapeseed, soybean, sunflower, palm oil), it is biodegradable and not dangerous for the environment. In some European Union countries, biodiesel is already present in fuels (in a certain percentage) and also some vehicles can already run on 100% biodiesel.
Biogas is generated by fermentation of waste from agriculture, households and industry. It consists of approximately 60 percent methane, 35 percent carbon dioxide, and 5 percent a mixture of hydrogen, nitrogen, ammonia, hydrogen sulfide, carbon monoxide, oxygen, and water vapor. Given the amount of methane it contains, biogas can be used as a fuel. The calorific value of biogas is proportional to the amount of methane. Biogas can be used to generate electricity, heat water and space, and in industrial processes. If compressed, it can replace natural gas used in cars with internal combustion engines.