Biological Energy

Biodiesel sample in flask. Image by Shizhao.

Biodiesel sample in flask. Image by Shizhao. License: GNU FDL

Biological energy sources can be broken down into the categories biomass and biofuel. Biomass is produced directly by living organisms such as wood, plant matter, and gases produced by micro-organisms. Biofuel is fuel derived from biomass through various processes for the purpose of making transportation of fuel easier, more efficient, or optimized for certain uses.

One of the major goals of bio energy is to produce a fuel that has a carbon neutral or even negative impact on the atmosphere. Plants and other organisms take carbon from the atmosphere as they grow. When biomass or biofuels are consumed for energy that carbon is then released back into the atmosphere. This is in stark contrast to fossil fuels which release carbon that has been out of the atmosphere for thousands of years.

Environmental Impact of Biological Power

Although one of the major goals of biofuels is producing fuel that has a neutral or negative carbon footprint but this can be offset by certain things. Crops used for biofuel production use carbon from the atmosphere which is released during combustion. This cycle doesn’t take into account nitrogen oxide and other pollutants and green gases released during the production and use of fertilizers, pesticides, and other agricultural aids that may be used.

Ethanol plant in Turner County, SD, USA. Image by Jon Platek.

Ethanol plant in Turner County, SD, USA. Image by Jon Platek.

Land use is another major factor in the environmental impact of biological energy. Growing crops for fuel takes large amounts of land that could otherwise be used for food crops or even preserved in a natural state. Using land to produce crops also depletes soil of nutrients of and can have major impacts on local water supplies due to leaching of chemicals from pesticides and fertilisers.

Biofuels in particular also have an impact on the supply of food crops which can cause changes in the price of food locally and globally. When corn is being used to produce ethanol instead of eaten the supply of corn is diminished and thus the price increases. Some studies have shown that this impact is not negligible and is already contributing to famine and negative food market fluctuations.

Types of Biofuels

All biofuels are derived from organic matter. One exception is cutting edge technology like microbes that convert water and carbon into hydrocarbons (gasoline and more) but these still use organic organisms to produce fuel. Most biofuels are produced from plant crops or waste with sugar cane and corn being popular choices. This biomass is altered by chemical or biological processes to arrive at the final biofuel product.

Probably the most popular biofuel in the average person’s life is direct use of biomass through burning. Wood (biomass) is simply ignited and the heat energy produced can be used for cooking and warmth.

Ethanol is a common biofuel that is most commonly produced by fermenting biomass with specific yeast that consumes sugars and produces ethanol as a waste product. Sugar cane and corn are popular biomass crops used to produce ethanol. Ethanol is a bioalcohol and the most popular bioalcohol but there are other biofuels like methanol which can also be bioalcohols.

Biodiesel gained a lot of popularity in the last few decades due to the rising price of oil and the fact that it can be used in any diesel engine. Transesterification modifies the fatty acid esters in oils and fat to biodiesel through exposure to alcohols. Unlike ethanol which relies on biomass crops high in sugar, biodiesel biomass needs to be high in oils and fats. This makes waste animal fat and crops like palm oil, soy, or flax popular choices for transesterification. It also explains why waste vegetable oil from restaurants and fast food establishments is so popular among biodiesel enthusiasts.

Diagram of a domestic biogas plant. Image by Unknown.

Diagram of a domestic biogas plant. Image by Unknown.

Biogas is obtained by exposing organic matter to microbes. Methane is one of the most popular biogases. One popular method of producing methane is by using an anaerobic digester (essentially a cylinder with the proper microbes) filled with cow manure allowing cattle ranchers to produce energy from manure.

Syngas (synthetic gas) is produced by combustion of biomass in an environment that is low in oxygen. Instead of igniting when the temperature is increased past the combustion point the organic matter being used will begin to produce syngas. Normal combustion produces carbon dioxide and water but syngas is actually carbon monoxide, hydrogen, and hydrocarbons. This mixture is a more efficient energy source when combusted than simply burning the original organic matter and using the heat energy.

There are many emerging biological energy sources that aren’t being utilised outside of laboratory and research settings. Genetically modified crops and microbes is one of the most promising of these technologies so far. Crops can be genetically modified to produce ideal biomass such as increasing sugar, oil, or carbon levels in the plant. Algaes and other micro-organisms are being modified to produce biofuels. One recent example of this is a modified E. Coli that can produce hydrocarbons from nothing more than water (hydro) and air (carbon) using sunlight for energy.

Biofuels in the News

United Airlines Will Fly On Biofuels From Los Angeles Hub – 2013-06-08
In a historic milestone for aviation, United Airlines signed a purchase agreement to buy 15 million gallons of biofuel for its flights out of its Los …
Biofuels From Waste Enzyme From Tiny Marine Wood-Borers … – 2013-06-08
A new enzyme capable of aiding in the cost-effective conversion of woody-waste into liquid fuel was recently discovered during research …
Oklahoma State Researchers Studying New Biofuels Production – 2013-06-08
Oklahoma State University researchers have published the first analysis of a genome they say has potential for the cost-effective production of …
A molecular switch for cheaper biofuel – 2013-06-07
Lignocellulosic waste such as sawdust or straw can be used to produce biofuel but only if the long cellulose and xylan chains can be …
San Diego-Based Algae Biofuel Strikes ‘Milestone’ Deal With Oil Giant – 2013-06-07
Above: Cellana uses marine microalgae to photosynthetically produce its line of Omega-3 EPA and DHA oils, animal feed, and biofuel …
Lack of woodwaste curbs biofuel sector – 2013-06-07
A major forestry report says promising downstream industries such as biofuels and biochemicals are unlikely to flourish if sawmillers don’t …
Volvo Trucks Takes DME Plunge, Biofuel Or No Biofuel – 2013-06-07
Volvo Trucks has ambitious plans for dimethyl ether (DME), which is more familiarly known as a propellant for spray-on cosmetics rather than a …
Unilever and Nestlé join aid charities to call for biofuel curbs – 2013-06-07
Unilever and Nestlé have joined development non-governmental organisations in calling on David Cameron to use the Group of Eight …
Biofuel Maker Cool Planet Energy Raises $29.9 Million – 2013-06-07
Cool Planet Energy Systems Inc., a closely held biofuel developer, raised about $29.9 million to build its first production facility, Chief Financial …
Biofuels address high electricity costs in island nations – 2013-06-06
Islands may provide a relaxing getaway from civilization, but their remote location has its drawbacks. In Anguilla, for example, electricity prices …


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