Introduction to Biomass energy
Biomass covers a whole gamut of energy forms. The definition of biomass is vegetable or plant matter, sometimes animal, that can be converted into an energy source.
Other fuel terms which also have biomass as their basis are biofuel, vegioil, bioenergy, bioethanol, biogas & etc.
The great advantage of biofuels is that they are considered to be 'carbon neutral' that is that they use up as much carbon dioxide during growth, as they expend as a fuel.
Care still needs to be taken however when calculating carbon neutrality - how much carbon is produced by farm or forestry vehicles - how much carbon is produced in fertilzer - how much carbon is produced in transport?
Biomass is a little-used term by the public generally, but when you think of wood fires and wood burning stoves it is easy to see that biomass fuel has been in use for centuries. In fact, in 2003, biomass heat and electricity generation accounted for 87% of renewable energy sources in the UK and about 1.55% of the total electricity supply.
Sourcing Biomass Biomass fuel can be sourced from waste or by-products from industrial or agricultural industry: such as wood waste from forestry or furniture industries; straw remains from wheat crops; chicken litter; sewage; manure; used vegetable oil.
There are also crops which are dedicated to energy generation such as coppicing, willow, miscanthus (elephant grass) and poplar.
Other crops are multifunctional where parts of the plant can be used to generate different forms of energy. For example, wheat ears can be used to create bioethanol and biodiesel, whilst the straw can be utilised in generating electricity.
Conversion to energy The various methods of converting biomass to energy include:
- pyrolysis - chemical decomposition through high temperature heating in the absence of air,
- gasification - conversion of solids into gaseous fuel
- anaerobic digestion - also in the absence of air - this is involves using bacteria for decomposition