Biofuels

We've had a look at the carbon footprint and ways in which we can reduce our personal carbon footprint. On a global scale, one of the proposed solutions to the problem of carbon emissions from transportation has been the growing biofuel industry. The question of whether biofuels are contributing in the fight against increased greenhouse gases and the greenhouse effect and are really the saviour we hope they'll be still rages.

What Is Biofuel?

Man has been using biofuels for millenia for heating and cooking purposes. Throwing a branch on a fire and huddling around it for warmth is an example of biofuel use in its simplest form. It’s only relatively recently that biofuels have been developed in a liquid form which may be used in petrol and diesel engines giving us our first sign that we are well on our way to replacing high polluting fossil fuels as our energy source in transportation. The issue of whether the production of biofuel as a liquid fuel is a more greenhouse friendly solution than using the traditional fossil fuels has become a hotly debated topic and later on there are a list of the pros and cons of biofuels.

Types of Biofuels

Firstly, though a little bit of a distinction should be made between two types of biofuels that are currently in the spotlight. First generation biofuels have been available for years now while second generation biofuels are close to becoming a reality.

First generation biofuels are made from food crop feedstocks while second generation biofuels are made from agriculture and forestry waste such as the straw left over after havesting a crop.

When looking at first generation biofuels there are two that are used commercially: ethanol and bio-esters.

Ethanol is made from sugar crops and corn / maize crops by fermenting the sugars produced in the plants. The ethanol is distilled out of the resultant solution. The way current gasoline specifications are regulated, ethanol can only be blended with standard fuel up to 10% in the US and 5% in Europe. Additionally, ethanol has lower fuel economy performance than gasoline so, although producing ethanol is cleaner than fossil fuel, more is needed to run your car.

Bio-esters are produced by a chemical reaction between vegetable oils from products such as rapeseed and soyabeen oil and alcohol. The result is a liquid which can then be blended with diesel to create biodiesel. Bio-esters can be used in low concentrations in current vehicles or in a pure form in modified vehicles.

The carbon emission reduction generated from the use of these two types of biofuels comes in at around 3% and 2.5% respectively.

We’ll turn our attention to second generation biofuels which are made from agricultural and forestry waste. A process has been developed to make a product known as cellulose ethanol from straw using enzymes. Potentially, the use of cellulose ethanol solves many of the problems that have arisen during the creation of the first generation biofuels, such as using a potential food source.

Advantages and Disadvantages of Biofuels

When discussing the pros and cons of biofuels, it’s probably fairest to concentrate solely on first generation biofuels because that’s what’s currently in commercial use.

Advantages

• Biofuels lower the use of unrenewable resources such as coal and oil.
  
• Power levels of carbon emissions are produced when measured from well to wheel. The greatest benefit will come from locally grown product.
  
• Air pollutants when burning biofuel blended products are greatly reduced.

Disadvantages

• Rainforest clearing has proceeded in order to create large scale agricultural land devoted to biofuel crops.
  
• A potential source of food is being used for food when world wide starvation continues to be a problem.
  
• Carbon emissions generated harvesting and hauling biofuel crops, particularly internationally, largely negates the carbon emission savings.
  
• Even greater levels of greenhouse gas is produced by clearing of tropical forests to plant sugar cane crops. Soil degradation, peat drainage and waste burning create even greater levels of carbon emissions.
  
• Large scale biofuel plantations in countries such as Indonesia and Brazil are unsustainable.

As can be seen, the idea that biofuels are the clean, green and sustainable answer to the growing oil shortage and emissions of greenhouse gases problem is premature at this stage. More definitive studies must be undertaken if the first generation biofuels are going to be a successful option, for the sake of the industry and the planet. It appears that there has been an initial grab for cash with little regard to the environmental consequences, in fact the very problems that are supposed to be solved.

Fortunately there is a lot of research and development going into the production of second generation biofuels with a very interesting breakthrough made in the creation of biocrude. This is an area that we will look at in a little bit more detail.