Biofuels can be described as any fuel that is derived from biomass ie living organisms or their metabolic by-products. For example, crops such as corn and dung from living animals
Although there is still somewhat of a scientific debate going on over the advantages of biofuels, it is thought that the main advantage over fossil fuels (coal,oil and gas), is that the burning of biofuels to release energy does not cause a net increase of CO2 levels in the atmosphere. This is because the source of the biofuel, crops for example, have already taken a corresponding amount of CO2 out from the atmosphere during their growth cycle when they photosynthesise. When this occurs, plants/crops release oxygen and retain the carbon to use as energy.
The carbon is then released when the crop is eventually burnt in order to release its energy. As long as new crops are planted in place of the ones that are burnt, there will be no overall increase in the amount of CO2 released into the atmosphere. So, whilst crop based biofuels don't reduce the amount of CO2 in the atmosphere, they are thought to be more or less carbon neutral.
The difference with fossil fuel deposits such as coal is that the coal deposits have been formed in the earth over millions of years and are therefore considered to be energy deposits rather than part of the energy cycle. The burning of fossil fuels on a scale required to satisfy mankind's energy needs, over a relatively short period of time, hundreds of years as opposed to the millions of years it has taken the deposits to form, means that the burning of such fuels, adds considerably to the levels of CO2 in the atmosphere. This in turn adds to the greenhouse gases already present in our atmosphere, and contributes to the warming of the Earth's climate.
Forms of biofuel
Biofuels can either be in solid form or liquid form.
Solid biofuels such as wood or even manure (dried cow dung) can be burnt to heat water which can then be used to power a turbine, which can generate electricity. Liquid biofuels, such as ethanol can be used as a substitute or be mixed with traditional fuels in automobiles.
Biofuel uses
The major benefit however probably comes from liquid biofuel, for the creation of Ethanol or biodiesel. Ethanol, a substitute for fossil fuel based petrol, and biodiesel, which is just diesel made with crops in place of oil which is a replacement for traditional diesel fuel in diesel motor vehicles. Whilst diesel cars are more fuel efficient than their petrol counterparts, biodiesel vehicles produce even less carbon dioxide. Neither are as efficient however as vehicles running on mostly ethanol-based fuels.
To run on fuel which has a greater than 10% mix of ethanol however, vehicles need a flexi-fuel modified engine.
The USA grows mainly corn crop, which can be converted to ethanol. In Brazil sugar cane is grown, and in the UK rapeseed is used.
Brazil is at the forefront of biofuel use, using it as a fuel in automobiles which have the flex-fuel engines needed to be able to run on pure ethanol.
Environmentally friendly or not?
Despite the benefits of using biofuels, there is a drawback however, which is the amount of land required to grow the crops necessary for the biofuel in the first place. There are already concerns that vast tracts of tropical rainforest like the Amazon in Brazil, are being cleared to plant sugar cane and other crops for biofuel production. Another problem is the cost of corn, an essential ingredient for basic food is also escalating causing further problems as the cost of certain products become unaffordable to many. It would surely be counter productive if such a situation were to develop where the CO2 absorbing tropical rainforests were being destroyed to plant crops to turn into environmentally friendly biofuels!
There is also a concern that as a by-product of growing the corn or other crop used for biofuel production environmental damage is caused by the fossil fuelled tractors, processes, fertilisers etc used in the growing process, meaning that they are not truly carbon neutral at all.
Recent research indicates that prairie grasses actually take out more carbon dioxide from the atmosphere during their growth than they emit when being converted to biofuel, meaning that they may well be truly carbon neutral.
It would seem more research is needed into biofuel production and use, but if grown responsibly, i.e not on land cleared of rainforest, a benefit may well be had for the environment by their use.
Copyright (c) 2008 Simon Rosser
This article is taken from The A-Z of Global Warming and discusses fossil fuels. The generation of electricity from burning carbon rich coal has a greater impact on the atmosphere than any other single human activity. In 2003 the power industry created 44.5% of all manmade carbon dioxide (CO2) according to the World Resources Institute, Climate Analysis Indicators Tool (CAIT). If one looks at emissions of carbon dioxide alone (ignoring all other greenhouse gases), then for the year 2000, the figure is just under 33%, and the latest figure available from 2003, as mentioned above shows an increase for this sector to 44.5%. The latest figure however excludes CO2 from land use change.
So what are fossil fuels, and how are they formed? Well fossil fuels form deep in the earth's crust over millions of years from enormous pressure and heat which converts dead plant and animal matter into hydrocarbons in the form of coal, oil or natural gas, which can then be dug up and burnt as fuel.
As these fossil fuels have formed over millions of years they are no longer considered to be part of the natural carbon cycle as they have effectively been "locked up" within the earth's crust and rocks etc.
In 2005 alone some 28 billion tonnes of CO2 was released into the atmosphere, from burning fossil fuels, which is equivalent to about 800 tonnes a second!
Out of all the fossil fuels the worst culprit is coal, which is used as the fuel in coal fired electricity power stations for the production of electricity. Generating electricity through carbon rich coal however has a greater impact on the atmosphere than any other single human activity.
The power industry creates over twice the amount of CO2 as is produced by the transport sector.
Basically electricity generation hasn't changed much from the 19th century with large power plants burning fossil fuels for the creation of electricity, and this model looks set to continue for some time to come.
Within the rapidly expanding economies of India and China, coal fired electricity plants will dramatically increase. In fact China, the USA and India are the top three producers in the world.
Apart from carbon dioxide, burning coal produces a host of other chemicals, such as sulphur dioxide, which causes acid rain, Nitrous oxide and other heavy metals.
What makes matters worse is that coal is the world's most widely available fossil fuel and there is around 200 years of coal left, if it is used at its current rate. This will be pretty academic however as according to the latest report by the Intergovernmental Panel on Climatic Change, if the burning of fossil fuels continue unchanged, the Earth could warm by as much as 6 degrees Celsius (10.8 F) by 2100. This would mean almost certain extinction of most of life on the earth.
One only has to look at pictures from recent news stories showing industrial cities in these developing countries to see the pollution and clouds of smog hanging over the cities and blocking out the sunlight.
It is estimated that by the year 2030, 55% of all power stations built in the Asia pacific region will be coal fired.
The transport sector in 2000 accounted for around 14% of greenhouse gas emissions, or 20% of CO2 alone (ignoring other greenhouse gases), in 2003. The majority of these emissions are from road transport, with aviation second, followed by shipping and rail last. Emissions from the aviation sector are expected to grow the quickest however.
So whilst developed and especially developing nations continue to build power stations to gobble up the Earth's supply of fossil fuels, serious harm is being done to the atmosphere which will continue to elevate global temperatures as higher CO2 levels add to the greenhouse effect.
There are in fact enough fossil fuels left to take the world to levels of CO2 concentrations of around 750ppm and above, (around 330 ppm more than present) which would elevate temperatures to such an extent that it would be catastrophic for all of Earth's inhabitants. CO2 as a result of burning fossil fuels is only one of the many greenhouse gases, which is contributing to the warming of the atmosphere. In the next article we will look at Earth's greenhouse gases, which are essential to life on Earth, but which are now warming the planet as their levels steadily increase.
Simon Rosser has sinced written about articles on various topics from Global Warming, Legal Matters. A lawyer by profession,I felt inspired to write a book entitled The A-Z of Global Warming, published in May 2008, after viewing Al Gore's documentary, An Inconvenient Truth in Nov 2006. Based on the most upto date scientific information, this Biofuel extr. Simon Rosser's top article generates over 14800 views. to your Favourites.