Fossil fuels

REMINDER ON FOSSIL FUELS

Climate Change: Worldwide, because of industrialisation and our lifestyle (excessive consumption and wastage), conventional energies (fossil fuels) are overexploited. Their disastrous effect on environment is now well known. 
The fossil fuels designate some fuels such as coal, oil and gas coming from rocks produced by fossilisation of biological material.
These rocks had absorbed CO2 from the atmosphere many millions of years ago. These fossil fuels, by burning, give off combustion products which, unless they are captured and stored, are emitted into the atmosphere, releasing the carbon sequestered back then dinosaurs and thus contributing to increased atmospheric concentrations and greenhouse gas emissions.
These are non-renewable energies the same basis as nuclear energy and they are becoming rarest and more expensive.

 Conventional fossil fuels

Faced with lower conventional fossil fuels, oil companies are looking at other fossil fuels.
Unconventional fossil fuels are a source of abundant energy at low cost. The impact on the economy and jobs is already important. There still remains a debate on the impact of these resources on the local and global environment.

Unconventional fossil fuels

Examples of unconventional fossil fuels:

• Oil shale, which must be exploited as coal, in mines with excavator and trucks. Oil shale contains kerogen (intermediate substance between organic matter and fossil fuels), which has yet to be pyrolysed. This type of oil is extracted primarily in Canada.
• Shale gases, which are gases, trapped inside rocks. To recover these gases, we must fracture the rock by injection of pressurised water and chemicals.
• "Heavy" oils so viscous that they flow very badly in the pipes. This type of oil is used in Venezuela.
• "Normal" oil but that we must seek very deep, under the sea or even under the ice of the North Pole!
• Tar sands containing asphalt and Oil sands containing bitumen. It is difficult to separate sand from petroleum. Also called "dirty oil", the industrial exploitation produces massive amounts of toxic sludge.
• Methane hydrates or "burning ice" extracted from the Arctic regions, offshore to several hundred meters depth.
• Peat is a little apart; his formation cycle is measured in thousands of years, which puts it halfway between fossil fuels (whose formation cycle is measured in millions of years) and renewable fuels.

In front of the announced depletion of these resources, other methods of use of natural resources are explored.
Here is an overview of the main techniques and sources of renewable energy.
Renewable energies (or renewables) are provided by resources than nature can regenerate as wind, water or sun. They are called “clean energy” or “green energy” as they do not pollute the environment. Their biggest advantage is that their sources are unlimited, unlike conventional fuels that are limited to a certain amount hidden under the surface of the earth.
Renewable energy is considered the ecological solution to the global problem of energy as clean alternative to fossil fuels, with no known harmful effects on our environment.
Today, renewables represent only a small portion of global energy production, and most of it is actually biomass, such as wood combustion (which is not the cleanest green energy). Renewables currently do not exceed 1% of global energy production, but they are expected to grow very quickly, especially with the growing awareness of global warming and oil prices, which are soaring.

What is Biomass?

Biomass is biological material derived from living, or recently, living organisms. In the context of use of biomass to produce energy, this word is often used to mean plant based material, but biomass can equally apply to both animal and vegetal derived material.
The burning of biomass releases CO2 into atmosphere but biomass growth recovers the atmospheric carbon.
If biomass is harvested as part of a constantly replenished crop, the carbon cycle is closed. There is, then, no net increase in CO2 levels.

What is Biofuel?

Biofuel is a fuel (solid, liquid or gas) that is composed of a recently dead biological matter. This is how a biofuel is distinguished from a fossil fuel, since fossil fuels are composed of “long dead” organic matter. In order to be considered a biofuel, the fuel must contain over 80% renewable materials.

Biofuels have many possible positive effects such as:

•  A reduced dependence on non-renewable fossil fuels,
•  A decreasing of greenhouse gas emissions,
•  An energy production in the user country with jobs on site.

While there are some naturally occurring greenhouse gases, most are human induced.

The four main human induced greenhouse gases are:

• Carbon Dioxide (CO2),
• Methane (CH4),
• Nitrous Oxide (N2O), 
• Fluorinated gases.

AZERTYUIOPThese four gases are a result of different methods of burning fossil fuel; whether in vehicles or factories.
By using biofuels (either in a car or in a factory), there will be less greenhouse gas emissions because biofuels burn cleaner.
Another benefit for biofuels is the fact that they are biodegradable whereas fossil fuels are not. 
The vital difference between biomass and fossil fuels is one of time scale to recapture the CO2.

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