please describe ethanol
¿como funciona el etanol?
Bio fuels provide the world with alternative source of energy derived from living things plants and animals.
What is carbon fixation?
What is ethanol?
How many convention parties are party to the Kyoto Protocol?
Biofuels are sources of energy that come from material that was recently living. This energy is derived from the process of photosynthesis where the plant uses the energy from sunlight to allow it to take carbon dioxide gas from the atmosphere and convert it into sugars and into the carbon containing structures within the plant.
The use of biological material (biomass) as a fuel or lighting material is not new - the earliest evidence for humans using wood for fires is at Gesher Benot Ya’aqov in Israel, 790,000 years ago. More recently, concern over the impact that the burning of fossil fuels is potentially having on the climate has resulted in renewed interest in biofuels.
The carbon containing structures within plant material can, for instance, be burned to release the energy they contain. Therefore, burning a biofuel releases carbon dioxide that was trapped only a few years beforehand and so is said to be ‘carbon neutral’.
The difference between fossil fuels and biofuels is that fossil fuels were produced millions of years ago when plants and other organisms died, became buried and were subjected to high temperatures and pressures forming coal, oil or natural gas. Biofuels, on the other hand, are produced from biological material that has been living recently.
There are a number of ways in which biofuels can be produced. Some biofuels can be produced from waste material, such as recycled plant oils, whilst others can be produced from plants specially grown for the purpose.
Both liquid and gaseous forms of biofuels can be produced from crops that either have a high sugar content, such as sugar cane or sugar beet, or contain starch that can be converted into sugars, such as maize.
Plants containing high levels of plant oils, such as oil palm or soybean, can also be used. Wood and its by-products can be converted into a variety of biofuels.
Plants capture carbon dioxide (CO2) during photosynthesis and store it in their tissues in a variety of carbon compounds (including both carbohydrates and oils).
These are often energy stores for the plant but they can also be harvested and processed to provide energy for human use.
At present, most of our energy comes from fossil fuels which originate from CO2 ‘locked up’ in plants by photosynthesis millions of years ago. When fossil fuels are burnt, CO2 is released into the atmosphere adding to the levels already present. Since the industrial revolution, there has been an acceleration in the burning of fossil fuels.
The levels of CO2 in the atmosphere are monitored by the Mauna Loa Observatory in Hawaii and are estimated to have risen from 280 parts per million (p.p.m.) in 1800 to 387 p.p.m. today.
When plants and animals die they may get buried in soil and eventually as more material is deposited on top of them, they are buried deep enough to be considered part of the rocks beneath our feet.
Thus the carbon has been transferred from the atmosphere to the rock, via animals, plants and soil. This is exactly what happened when fossil fuels such as oil, coal and gas were formed millions of years ago.
The Kyoto Protocol from the United Nations Framework Convention on Climate Change, which came into force in 2005, legally commits countries that signed the protocol to reduce emissions of four greenhouse gases, including CO2.
One of the ways in which this could occur is by a shift away from fossil fuels to biofuels.
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