Bioethanol Electricity

What is bioethanol?

Bioethanol is an example of a renewable energy source because the energy is produced by using an organic substance and sunlight, which cannot be depleted. Up to now, bioethanol has been primarily produced for fuel and used in vehicles, but experts believe this technology can be applied to electricity generation as a green, low carbon alternative. Recent trials have shown that burning bioethanol as a fuel vs. other fuels such as natural gas and diesel fuel emits a reduced level of greenhouse gases such as nitrogen oxides, carbon dioxide and sulphur oxide.

Bioethanol fuel production

Bioethanol is an alcohol made by fermenting the sugar components of plant materials and is made mostly from sugar and starch crops. Creation of ethanol starts with the growth of plants via a process known as photosynthesis which grows a series of feedstock such as sugar cane and corn. These feedstocks are then processed into ethanol, first using enzyme digestion to release sugars from the stored plant starch, which are then fermented, distilled and finally dried. Bioethanol is already the most commonly used biofuel in the world, and is especially prominent in Brazil.

Bioethanol used for electricity generation

Burning bioethanol via combustion produces a lower thermal energy output than other thermoelectric generating processes from fuels such as coal or oil. To generate the same level of energy and electricity a much larger stock of Bioethanol is required. The advantage however is that this is a carbon neutral fuel. During the plant growth process, the plants remove CO₂ from the atmosphere, and when they are burnt they release this gas back into the atmosphere, therefore the whole process is carbon neutral where as burning coal or oil adds CO₂ to the atmosphere.

The future of bioethanol in producing electricity

The world’s first bioethanol power plant is located in Brazil, opened for testing in early 2010, with an 87MW capacity, enabling it to provide power for over 150,000 inhabitants. The power plant is looking to generate electricity on a commercial scale using sugar-cane bioethanol as one of the key fuels. Testing on emissions from this power plant have shown a 30% reduction in greenhouse gases such as nitrogen oxide, without an impact on its power generating capacity.

In the UK we are probably not best suited to expolit this fuel as a green electricity generating source; with Windfarms, Wave and Tidal Energy probably being the best suited to our unique topography. Bioethanol on the other hand is heavily used as a blended transportation fuel in the US and Brazil. This is because mass production and cultivation of high yielding crops currently takes place in those countries.

However with recent trends forcing the pricing of crops and food upwards has meant that enthusiasm for this fuel source as a full alternative to conventional fossil has been slightly reduced.

Benefits

• Renewable energy source – it relies on sunlight & photosynthesis process which doesn’t diminish.
• Reduced emissions of greenhouse gases from the combustion process vs. other fossil fuels.
• Works well as an “add-on” fuel, a blending substance to conventional fuel.

Limitations

• Bioethanol relies on crop yields and crop prices as an input – therefore higher prices make the substance less economical.
• The combustion process produces less energy than conventional fuels such as oil and coal.