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Biofuels

Enzymes eating away at straw and oil squeezed from algae. These are just two of the technical programmes Shell is pursuing in developing better biofuels that could see CO2 reductions and a sustainable alternative fuel source.

From plant to pump

There are two main forms of biofuel today: ethanol – the most widespread biofuel made through basic fermentation of starchy or sugary plants; and FAME (Fatty Acid Methyl Esters) converting vegetable oil into a diesel type fuel via a process called transesterification.

The first generation of these biofuels has largely relied on food crops such as wheat or sugar cane as their source. The challenge Shell is now taking on is to develop the second generation by finding a source material that does not compete with food crops, a conversion process that will produce a low CO2 and a fuel with high performance. All this and it needs to be cost-competitive too.

Biofuels farm

Second generation solutions
Cellulose, the tough molecules that make up cell walls in plants, can be found in a number of forms including straw. However, to break down the cellulose tough new enzymes are needed to act as a biological catalyst and separate it from the rest of the plant to produce ethanol. Shell is working with Canadian firm Iogen and Codexis in the USA to pursue this solution.

In the future, algae may also provide a sustainable source of vegetable oil for the production of biofuel for diesel engines. In 2007, Shell announced plans to build a pilot facility in Hawaii with partner HP Biopetroleum to investigate the potential. It is early days but algae holds promise because they grow rapidly, and can be cultivated in ponds of seawater, minimising the use of fertile land and fresh water.