Introduction
The name “Biomass” was invented in 1975 to describe natural materials used as energy sources, and refers to organic matter which can be converted to energy. Biomass energy is the oldest source of energy in the human history, as it can be easily dated back to man’s first fire.
From the present available information and data concerning biomass, it’s supply, at the present, counts for 14% of the world energy sources (IENICA, 2007). In the developing countries 40% of energy is derived from biomass, while in the USA it count for 4%, Sweden 14% and Austria 10% (Hall et. al. 1992).
The Process
In biomass, a process called photosynthesis enables plants to capture sunlight and transform it into chemical energy, as shown in this equation:
CO2 + 2H2 Heat Light([CH2O] + H2O) + O2
The organic resources that are used to produce energy using these processes are collectively called “biomass”.
The Elements
The main chemical elements in biomass are carbon and hydrogen, with others in addition, such as Oxygen, Nitrogen and sulfur. The last element, however, exists only in very small quantities.
The Energy
Biomass energy can be obtained by reversing the photosynthesis process. The stored energy is released when the chemical compounds within the biomass materials are broken down.
Biomass is a good source of renewable energy but, generally speaking, it is not a good fuel, as it typically contains more than 70% air and void space. Consequently, this low volumetric energy density makes it difficult to collect, ship, store and use.
Types of Biomass
Biomass includes forest and mill residues, agricultural crops & wastes, wood & wood wastes, animal wastes, livestock operation residues, aquatic plants, fast-growing trees and plants, and municipal & industrial wastes.
Therefore, various types of organic materials can be burned to produce energy or converted into a gas which can be used as fuel.
Research in this area has shown that the net energy available in the biomass materials when they are combusted ranges from about 8MJ/kg for green wood, to 20MJ/kg for oven dried plant matter, to 55MJ/kg for methane; compared with about 23 – 30MJ/kg for coal (Fletcher S., et al., 2005).
Types of Biomass Energy
Biomass energy can be divided into two categories: modern biomass and traditional biomass. In most cases the modern biomass involves large-scale uses as it tries to replace the conventional fossil fuel energy sources still being used in various parts of the world. These large scale uses may include forest wood and agricultural residues, urban wastes, biogas and energy crops. Most traditional biomass is generally found in developing countries. Biomass materials in this case may include various types of wood, charcoal, rice husks, animal dung and other plant residues (Fletcher S., et al. 2005).
There are two main available options for utilising biomass:
1. Construction stand alone (or dedicated biomass) – are defined in the Renewable Obligation as those which have been commissioned since 1 January 1990 and are “fuelled wholly by biomass in any month” (dti Carbon Abatement, Technologies Programme 2005). 2. Co-firing of biomass with other fuels.
We know that 40% of the European Union’s energy supply depends on oil imported from OPEC countries Various research and studies predict that in the coming years that there will be an increased dependence on oil and gas imports, this will result in the share of imports in the European Union (EU) up to 70% by 2030 (Ignaciuk A., et al. 2004).
Plants “Energy Crops” Examples
Generally speaking, any type of energy crops can be used as a biomass materials for the purpose of generating energy, however, considering that the aim of various biomass projects in general and this project in particular is to generate energy economically viable on commercial scale, then the selection process in choosing the most suitable biomass materials would have to undergo strict testing from scientific and technical factors to the market, business and regulations factors. Having said that, presently there are a number of popular examples presently being researched and/or used as an example of the types biomass materials with possible future commercial use. One of these examples is “Short Rotation Coppice” (Defra. Department of Environment, Food and Rural Affairs 2002). The following are few popular examples:
1. Alfalfa (fixes nitrogen in the soil).
2. Willow.
3. Switch grass (protects the soil and the water in watershed).
4. There are a wide range of crops that can be used for biodiesel production,
such as Canola (Rapeseed), Palm oil, Sunflower oil, Soya Bean oil, animal
fat (Tallow) as well as recycled oil (e.g. frying oil).
5. Common crop residues (waste matter).
6. Sorghum.
7. Forestry Crops – Fast growing trees, which should be suitable for coppicing. Coppicing involves harvesting the tree after a few years and then allowing the tree to sprout again from the stump, followed by subsequent harvesting (usually between 2 – 5 year periods).
8. Forestry Residues – Generated by operations e.g. thinning of plantations, natural attrition, extracting stemwood for pulp and clearing for logging roads. Various types of work on wood can also generate large volumes of residue, such as sawdust, bark and woodchip rejects and off-cuts. There are plenty of these types of by-product materials around but they are usually not being utilised.
Conclusion
Biomass in general, among other renewable sources of energy, is the science and technology for a new type of energy many predict would be the challenge during the 21ast Century. The research and investigations of various biomass materials, for long term commercial global fuel use, is the challenge of today and the investment for the near future. These investigations are expected to produce the required materials and technologies to replace the fossil fuel, in particular crude oil, which will be exhausted sooner or later.