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Biomass is considered as a source of renewable energy; but with the cultivation of crops for biomass for processing to biodiesel becoming more popular worldwide, some adverse effects on the indigenous people and the environment are becoming evident.
This is an article on biofuels and in particular the effects on modern agriculture of the production of biodiesel.
We begin with a look at the crops cultivated for biomass and the processing of these to biodiesel.
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Crops Used for Biodiesel Processing
Biodiesel can be processed from the following crops:
Basic Overview of Biodiesel Processing
This process is known as transesterification, that is, the chemical process of crushing crops to extract the oil which is stored in a stainless steel vat. The base oil contains esters of long-chain fatty acids, which are converted to methyl esters by an alcohol and catalyst.
A catalyst such as sodium hydroxide and an alcohol such as methanol are added to the oil and vigorously stirred then left to settle for 24 hours. After this time the supernatant mixture has converted to biodiesel, and glycerol containing the catalyst and the alcohol. These are washed out using water filtration processing and vacuum drying to leave just biodiesel. The glycerol is a valuable by- product along with animal feed from the spent feedstock.
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Negative Effects of Biodiesel on Modern Agriculture
Processing biodiesel from crops normally used for human consumption has produced the following undesirable effects:
1. Food vs. Fuel Conflict
Unwanted competition between the fuel producers and the indigenous people is creating an ongoing conflict.
2. Land Use
The profit made by the biodiesel fuel producers is such that they can pay a good price for their feedstock crops. This encourages poor people to grow more crops using reclaimed land from deforestation.
3. Environmental Impacts
A) Fertilizer usage
The crops are often forced to grow faster and give bigger yields by the application of fertilizers. These fertilizers contain major chemical nutrients such as nitrogen, phosphorus, ammonia and potassium, along with other micro-nutrients of calcium, magnesium, sulfur.
These leach into the watercourse causing pollution, and eutrophication to rivers and the sea in coastal areas. The soil will gradually become depleted due to the lack of required trace elements, eventually becoming barren.
The production of fertilizers also requires high levels of power, with the attendant emission of greenhouse gasses.
As land for growing the crops becomes scarce, more forests, including rainforests are being cleared to make way for cultivation of crops for biodiesel. This not only destroys habitats but reduces the amount of CO2 absorbed naturally by trees.
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Mitigation - Improvements Being Made
- European laws are coming into force in 2010 which will govern the amount of crops grown for production of first generation biofuels, including biodiesel. First generation fuels are those produced from edible crops. The legislation will also contain guidelines to the type of crops used with the least effect on the indigenous, land usage and the environment.
- As of 2006, the application of nitrogen fertilizer is being increasingly controlled in Britain and the United States.
- Second generation biofuels are produced from by the lingo-cellulose process (this is the use of the cellulose in leaves and stems for crops) which are not used for human consumption, such as grasses, or from left over leaves/stalks or roots. Although sometimes more expensive processing is involved, costs are coming down as new sources such as algae are being developed.
- Several reports on the problems associated with biodiesel processing from crops have been published in the USA. The most recent one by Princeton University addressed the clearance of rainforests for crop cultivation and stressed the need for sustainable biofuels. Farm animal waste, crop cultivation on marginal land and the production of secondary generation biofuels was recommended.
- Fertilization of crops- more control as indicated above, plus the use of natural fertilizers like animal manure, seaweed based fertilizer, worm castings and natural fixatives such as clover.
- Payment to farmers in lieu of growing crops for biodiesel. This idea has been mooted in several countries and could eventually become applicable. However in today’s financial climate it does not seem likely to come about.
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The effects of biodiesel on modern agriculture and improvements being made are a subject being discussed worldwide. Crops grown for fuel rather than for human consumption are on the increase, causing major conflict between the growers, the fuel companies and the poor people who are losing some of their food to fuel production.
However, improvements are being slowly made. In Europe new legislation on the use of fertilizers and the amount of land allowed to be used for production of crops for biodiesel are being drawn up. Hopefully these will spread to the major producers of biofuels worldwide.
There are also second generation fuels being produced from inedible crops such as algae which although more expensive than first generation biofuels could lead to improvements to the current processing of biodiesel.
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