Alternative sources of energy
Alternative sources of energy
There are several alternatives of energy that can provide renewable energy. Renewable energy is usually generated from the natural resources such as wind, sunlight, rain, geothermal heat and tides. Some of the renewable technologies range from wind power, solar power, biomass, hydroelectricity and biofuels for transportation, (Chiu et al). Biofuel This can broadly be defined as liquid, solid or gas fuel that is derived from recently dead biological materials mostly the plants.
It is thus distinguished from the fossil fuel that is generated from the long dead biological materials. Biofuels are theoretically produced from a biological carbon source. Photosynthetic plants are the most common source of biofuels since different plants as well as plant derived materials are all used in the biofuel manufacture. Use of biofuels is common in Asia, Europe and also in America, (Anselmo, P. , & Badr, O). The use of this renewable biofuels does provide increased energy security and independence from the petroleum since it is a renewable source of energy.
Various issues that form part of the recent debates on the use or no use of biofuels include; the fuel versus food debate, effect on oil price, carbon emission levels, sustainability, soil erosion and deforestation, its impact on available water resources, the potential of poverty reduction, human rights issues, its price, its efficiency and energy balance and the comparison of the centralized versus the decentralized models of production, (Powlson et al). The greatest challenge in the use of biofuels is the conversion of biomass energy to liquid fuels that can be transported.
The two most common strategies that re employed include; 1. Growing of sugar crops such as sugar beet, sugar cane or starch such as maize/corn and then employ a yeast fermentation process to produce ethanol (ethyl alcohol). 2. Growing of plants such as soybean, oil palm and algae that do naturally produce oil. These oils can be directly burned in diesel engine since heating of oils reduces their viscosity or they can further be processed chemically to produce biodiesel.
A good example is the conversion of wood as well as its byproducts into methanol, woodgas or ethanol fuel, (Batistella et al). First generation Biofuels This refers to biofuels that have been made from starch, sugar, vegetable oil or even animal fats by employing the conventional technology. Grains or seeds such as wheat when fermented into bioethanol are the basic feedstock used in the production of first generation biofuels. Sunflower seeds are also used to yield vegetable oil that is used in biodiesel.
The feedstock used for the first generation biofuels have even found their way to the human and animal food chain and has thus been criticized for the diversion of human food into the production of fuels a move that has potentially caused food shortages as well as increase in food prices, (Chiu et al).. Though the quality of obtained oil for use as fuel maybe lower, vegetable oil can be used in some of the old diesel engines that were equipped with the indirect injection system though only in warm climates.
In most of the instances, vegetable oil has been used to manufacture biodiesel that is diesel engine compatible especially when blended with the conventional diesel. An advantage to this is that most of the used vegetable oil is being processed into biodisel though it is also worth to note that such companies as Wartsila, MAN B & W Diesel and Deutz AG do make engines that are fully compatible with vegetable oil, (Warabi et al). Biodiesel In Europe, this forms the most common biofuel. It is a liquid that is similar in composition to mineral diesel and is produced through the process of transesterification from fats or oils.
It’s chemically regarded as FAME (fatty acid methyl (or ethyl) ester. Methanol (or ethanol) and sodium hydroxide are mixed with oils and the chemical reaction that results produces glycerol and biodiesel (FAME). For every ten parts of biodisel produces, one part of glycerol is also produced. Some of the feedstocks used to produce biodiesel include rapeseed, soy, jatropha, mustard, mahua, flax, palm oil, sunflower, field pennycress, hemp and algae, (Shah, P. S. , & Suppes, G. J). When mixed with the normal mineral diesel, biodiesel can be burnt in any diesel engine.
Most people have been able to run their vehicles purely on biodisel and have not reported any problems though in circumstances of lower temperature, it has the tendency of becoming viscous/thick and some vehicles may thus require a fuel line heater. Most of the vehicle manufacturer taking a precaution on this give out a 15% recommendation of biodiesel that is blended with mineral diesel though most of the newer diesel engines are being made in such a manner that they can run on with 100% biodisel without having to alter the engine, (Schumacher et al).
In the US, the rate is not the same as in Europe since more than approximately 80% city buses and commercial trucks in USA are on diesel. It can thus be said that the US market for biodisel is one that is growing at a very slow rate, (Chiu et al)… Bioalcohols Through the action of enzymes and microorganisms in the fermentation of starches or sugars, alcohols such as ethanol which is most common and the less common ones such as butanol and propanol are produced.
Biobutanol is now regarded as a direct replacement for gasoline since it can be directly used in gasoline engine just as biodisel is used in diesel engines, (Dasari). Ethanol the worldwide common biofuel. Methods used in the production of are enzyme digestion. It can be used some of the petrol engines to act as a replacement for the commonly used gasoline or can as well be mixed to any percentage with gasoline. Worth noting is that most of the currently existing petrol automobile engines can run with a mixture of up to 15% bioethanol and gasoline/petroleum.
Also a mixture of ethanol and gasoline has higher octane thus implying that the engine does run more efficiently and even burn hotter. Another advantage is that a mixture of ethanol and gasoline is recommended as a winter oxidizer in high altitude air so as to minimize the atmospheric pollution, (Emerson). The disadvantage of using ethanol as a form of fuel is that it has less energy content and thus it would take more fuel to cover the same distance as compared to the conventional diesel. It is also highly corrosive to the fuel systems, aluminium, rubber hoses and gaskets and combustion chambers.
Though an ethanol powered aircraft has already been developed, Embraer EMB 202 Ipanema, it is illegal to use alcohol containing fuels in aircraft. Ethanol is also not compatible with the marine fiberglass fuel tanks as it makes them leak and for the 100% ethanol vehicles to be used, the normal engine has to be modified. It is also a great disadvantage to note that it is not possible to transport corrosive ethanol in the normal petroleum pipelines and thus a more expensive system that would involve stainless steel tank trunks would definitely increase the energy and cost consumption to deliver it to the customer, (Dasari).
Less motivating is the net energy gained. When all the energy consumed in cultivation, farm equipment, planting, pesticides, fertilizers, fungicides and herbicides, irrigation systems applied, harvesting and transport, processing and transport to the fuel terminals when also considering the fact that ethanol has lower energy content, the net energy value that is delivered to the consumer is very small, (Shah, P. S. , & Suppes, G. J).
To counter these challenges of bioethanol, some of the manufactures make flexible-fuel vehicles (FFV’s) that do run on either petrol or bioethanol and even up to the 100% bioethanol mark. These kinds of vehicles have an exhaust oxygen sense system that is designed to adjust the computers system and thus the fuel injection system accordingly. Unfortunately, this leads to increased acquisition cost as well as maintenance cost. When maintenance of the FFV is needed, pollution emission increases and efficiency falls despite the ratio of the mixture.
Worth noting also is that the FFV combustion engines are increasingly becoming more complex impacting directly on cost both of maintenance and reliability. Alcohol does also mix with water beyond blending well with petroleum and thus there is the potential of ethanol fuels absorbing environmental moisture despite being dried. Conclusion Countries such as United States of America are searching for alternative sources of energy and the USA aim is to replace the 75% imported oil with alternative energy sources by the year 2025, (Ramos, L. P. , & Wilhelm, H. M).
The difficult task for the world is to weigh the advantages as well as disadvantages of alternative sources of energy in comparison to the conventional diesel. It should not be forgotten that the main source of ethanol for use as a biofuel is from corn yet the world is experiencing food crisis. It thus appears that there yet more that the world has to streamline in order to enjoy fully the benefits of biofuel.
Subject: Alternative energy,
University/College: University of California
Type of paper: Thesis/Dissertation Chapter
Date: 11 January 2017
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