Renewable energy sources

Traditionally, wood is the main form in which biomass is use as an energy source. The biomass is employ to boil water to provide steam to fling turbines. In Great Britain most commercially produced wood is employ for musical note, just now when a conifer plantation is felled, there are branches and low-grade timber that fag end be used for furnish.Straw left over from garner ce solid crops can also be used to produce energy. When used for energy the cost of collecting, storage and transporting bulky problems is a problem. Most examples assert on a community-based collection used locally in a close plant or used on the farm that produced the stubble and is widely used in Denmark and the USA. Stubble used to be destroy, solely this was made illegal in the UK. Most stubble is used for bedding. When burnt straw leaves ash, which contains nutrients, which can quickly be extr symbolizeed from the soil by the naked as a jaybird crop. This method is still used in many developing countries. It is really rarely ploughed in as it takes along time to biodegrade and as it does so it creates anaerobic pockets in the soil.Wood can be secondhand as a renewable resource if fast growing species are used. In the UK willow is used (popular was also used once). The plants are heavy(a) close together then once a sufficient rout system is established they are coppiced. Then all new growths when of the arrange length are harvested and chipped. Once the willow is dried and then used. This is frequently used on low quality land (marginal) or cross out aside, or areas where biological control is being encouraged.Biomass to GasoholFermentation of sugar by yeasts switch overs the energy in sugar biomass to ethanol, which can then be used as a go off. Gasohol is made of 80-90% unleaded petrol and 10-20% ethanol and is used in cars (It can be used in pure form, entirely petrol is added to stop people drinking it). The sugar is obtained from sugar welt and sugar beet. This form has been relatively unsuccessful.Sugar cane is grown in tropical areas, where as sugar beat is grown in temperate countries. The sugary sap is extracted and then treated to come to molasses, which is then stored until it is undeniable for fermenting. Ethanol is a much cleaner fuel and produces much less(prenominal) pollution, but it is much more expensive to produce. Especially as the farmers can also sell the crop to be made into refined sugar. This issue is unlikely ever to work due to politics and the oil industry. In the end it can not be considered as a real alternative ,as 80-90% of it is made from a fossil fuel. Once the sugar is extracted the stringy residue (bagasse) is dried and then burnt as a fuel to ferment the malasses.1) Growing and cropping of sugar.2) Extraction of sugars by crushing and washing cane.3) watch glass out of sucrose (for sale) leaving the syrup of glucose and fructose (molases)4) Fermentation of molasses to outlet dilute alcohol.5) Dist illation of dilute alcohol to give pure ethanol, apply bagasse as a power source.A more promising is oil-rich seed rape which has been used to power buses in certain areas of the UK as fall apart of a trial and in Italy, it is added to diesel and can be added to make up 30% of the mixture (rpae methyl ester, RME). It produces fewer sooty particles and no sulphur dioxide. Also coconut oil in Philippines, palm and opera hat oil, Brazil and sunflower oil in South Africa.Domestic rotDisposal of domestic and industrial abandon has become a voluminous problem around the world. In the UK about 300kg of run off is produced per person per year. chuck out the waste causes many problems e.g. leakage of pollution and using up land. It ability be possible to burn the fuel for energy (cellchip in the UK in London does this but people have to separate some of the waste first. However, all the houses that take part close to the plant reciev free blistery water.)Some landfill sites have b een constructed to collect the gas (methane) produced from the anaerobic conditions for use.Agricultural waste (Biogas)Biogas can convert the energy in biomass into biogas, a gaseous fuel that consists mainly of methane, by fermentation. Typically biogas is made of65% methane, 35% CO2, with tracea of ammonia, total heat sulphide and water vapour.usually dung (slurry) from farm animals is used in the fermentation process so that waste products are turned into something useful, as the leftover sludge can be used as a fertiliser.The digestion process occurs in 3 stages1) Aerobic bacterium convert lipids and carbohydrates in the biomass into sugars, fatty panes, amino acids and glycerol by hydrolysis (0-10 days, acids cause pH to fall).2) Acetogenic bacteria convert sugars and other products of stage 1 into short-chain fatty acids e.g. acetic acid = acetogenesis (stages 2+3, 10-45 days acids used up, pH increases, methane produced.).3) Anaerobic bacteria convert the fatty acids into methane = methogenesis. Conditions must be anaerobic as the bacteria are only active when there is no oxygen present. They are called tie anaerobes. Temperatures must be kept between 30-40o because the bacteria are sensitive to temperature changes.The reactions take place in a digester. It must bei) potent and large enough to hold large volumes of liquid and withstand haul build up.ii) Gas-tight and allow aerobic conditions to be affirmed.iii) Have an breathing in for loading material, an outlet for the gas and a way of unloading the residue.iv) be buried in the ground to help withstand pressure and act as an insulator.Often several digesters are used together to maintain a continuous supply of gas. It provides a useful way of acquiring rid of animal waste. (eutrophication)