RENEWABLE ENERGY RESOURCES
PROF. DR. S.M. ALAM
Nov 29 - Dec 5, 2010
Renewable energy refers to any of a large number of sources of energy production that do not depend on fossil fuels or nuclear power to operate. A short list of these technologies includes solar, wind, rain tides, hydro, hydrogen, geothermal power, and biomass.
The main goal of alternative energy research is to provide a low-cost source of energy that does not rely on unsustainable resources such as coal or oil. By making use of resources that cannot be depleted, like sunlight, alternative energy provides a way to meet the needs of a growing civilisation without the negative environmental impact. The best type of solar energy to use in an area depends largely on the geography of that area. Desert lands, for instance, receive more than enough sunlight to make use of solar energy, but might have a hard time implementing a hydroelectric energy source. Scientists continue to work on several sources of renewable energy as a result of this fact, which will lead to better energy solutions in the future.
Renewable energy is an umbrella term that refers to any source of usable energy intended to replace fuel sources. Alternative energy saves natural resources and it is environmentally superior to conventional coal and oil. Wind, flowing water, energy conservation and geothermal heating are ancient, but now employ new advanced technology. Technologies such as solar cells, hydrogen and fuel cells and ocean energy are relatively new. All of the technologies operate. The present cost effectiveness of some of the newest technologies varies.
In summary, the alternative energy includes three main groups: i) Renewable energy (solar, wind, hydro, geothermal, biomass) ii) Fuel cells and hydrogen, and iii) Energy conservation and enabling technologies.
Renewable energy saves natural resources and is environmentally superior to conventional coal and oil. Renewable energy sources are free and have lower carbon emissions than what we have now. Each of these four segments involve very different technologies and investment concerns.
In 1917, Alexander Graham Bell advocated ethanol from corn and other foodstuffs as an alternative to coal and oil, stating that the world was in measurable distance of depleting these fuels. Since the 1970s, Brazil has had an ethanol fuel program which has allowed the country to become the world's second largest producer of ethanol (after the United States) and the world's largest exporter. Brazil's ethanol fuel program uses modern equipment and cheap sugar cane as feedstock, and the residual cane-waste (bagasse) is used to process heat and power. There are no longer light vehicles in Brazil running on pure gasoline. By the end of 2008, there were 35,000 filling stations throughout Brazil with at least one ethanol pump. Cellulosic ethanol can be produced from a diverse array of feedstocks, and involves the use of the whole crop. This new approach should increase yields and reduce the carbon footprint because the amount of energy-intensive fertilisers and fungicides will remain the same, for a higher output of usable material's of 2008 there are nine commercial cellulosic ethanol plants which are either operating, or under construction, in the United States. The process of producing oil, coal, or natural gas fuel is a difficult and demanding process that requires a great deal of complex equipment, physical and chemical processes.
On the other hand, alternative energy can be widely produced with basic equipment and naturally basic processes. Wood, the most renewable and available alternative energy, burns the same amount of carbon it would emit if it degraded naturally.
Algae fuel is a biofuel which is derived from algae. During photosynthesis, algae and other photosynthetic organisms capture carbon dioxide and sunlight and convert it into oxygen and biomass. The benefits of algal biofuel are that it can be produced industrially, thereby obviating the use of arable land and food crops (such as soy, palm, and canola), and that it has a very high oil yield as compared to all other sources of biofuel. Biogas digestion deals with harnessing the methane gas that is released when waste breaks down. This gas can be retrieved from garbage or sewage systems. Biogas digesters are used to process methane gas by having bacteria breakdown biomass in an anaerobic environment.
The methane gas that is collected and refined can be used as an energy source for various products. Hydrogen gas is a completely clean burning fuel; its only byproduct is water. It also contains relatively high amount of energy compared with other fuels due to its chemical structure. This process is known as biological hydrogen production. It requires the use of single celled organisms to create hydrogen gas through fermentation. Without the presence of oxygen, also known as an anaerobic environment, regular cellular respiration cannot take place and a process known as fermentation takes over. A major byproduct of this process is hydrogen gas. If we could implement this on a large scale, then we could take sunlight, nutrients and water and create hydrogen gas to be used as a dense source of energy.
Floating wind farms are similar to a regular wind farm, but the difference is that they float in the middle of the ocean. Offshore wind farms can be placed in water up to 40 metres deep, whereas floating wind turbines can float in water up to 700 metres deep. The advantage of having a floating wind farm is to be able to harness the winds from the open ocean. Without any obstructions such as hills, trees and buildings, winds from the open ocean can reach up to speeds twice as fast as coastal areas.
In contrast, because wind power has been harnessed for over 100 years, its underlying technology is relatively stable. Its economics are largely determined by siting (e.g., how hard the wind blows and the grid investment requirements) and the prices of steel (the largest component of a wind turbine) and select composites (used for the blades). Because current wind turbines are often in excess of 100 meters high, logistics and a global manufacturing platform are major sources of competitive advantage.
In the present day world, the dispersing wind has been proved as a powerful natural source for generating electricity in most countries of the world, where the powerful wind resource is available. Around the world, the renewable energies targets have been set and the last decade saw an immense increase in the world wind energy output. To generate any measurable power from wind, we need strong wind speed, of more than five meters per second.
Another problem with the speed of the wind is that it should be steady and consistent throughout the day. China which has been generating more than 3,450 MW from wind has an impressive record of 156 percent increase of wind energy during recent years. Spain is producing 15,100 (40 percent) MW of their energy demand from wind. The United States of America has seen great boom in the last decade and generates 19,540 MW from on-land and offshore wind farms.
The US has vast areas of seashores from Maine State in the East to Washington State in the West. The USA has started its wind energy mill in 1940 and Europe in 1923. At present, there are 28 European countries full of natural resources and having brotherhood relations. Denmark is producing 8312 MW through coastal wind. A number of other countries including Italy, the UK, Holland, Portugal, Finland, Sweden, Ireland, Japan etc. have crossed the 3,000 MW mark of installed capacity.
Windmill is the most environment friendly source of power. It had been reported that every single installed MW of wind power saves approximately 2,000 tons of CO2, 22 million cubic feet natural gas and 25 million litres of HSD in terms of environment and fuel bill. According to a survey report from Euro barometer published in January 2006, almost 80 percent of European Union citizens prefer renewable energies as alternate to high-priced oil and gas, while nuclear is preferred by only 12 percent.
Pakistan is yet to embark on the generation of renewable energy. The country is far behind on electricity generation through wind energy. The Alternate Energy Development Board (AEDB) was founded in May 2003 for supplying wind/solar energy in remote regions of the provinces.
Pakistan has a long coastal belt of 1050 kilometers from Sindh to Balochistan highly suitable for wind energy generation. To generate power from wind, we need strong wind speed of more than six meters per second.
In the long coastal areas, the dispersing wind blows from March to November in almost normal speed. Due to its ideal geographical location, Pakistan possess immense potential to harness unlimited solar and wind energy. The average wind speeds of 5 to 7 meters per second are available in most of the coastal areas in Sindh and Balochistan as well as in a few northern valleys of K-P and AJK which are suitable for producing electricity.