The Continued an Unlimited Supply of Energy - Essay Example

Harris Kamran Development Studies 16 December 2007 Renewable Energy Constraints If there is one factor that the human society as a whole is completely dependent on today more than ever, it is the continued and unlimited supply of energy. Like any other dynamic system, human society, too, is in need of an external source of energy to keep its processes functioning and for maintaining its stability (Physics Today 2004). The sources of energy at our disposable can be divided into two broad categories; renewable and non-renewable energy sources. The huge chunk forming the non-renewable sources are the fossil fuels, and they form the backbone of modern human technologies and society, basically, maintaining human civilization today. The utter dependence of man on this form of energy is not very encouraging, for the simple reason that this source of energy, as its name suggests, is not a permanent supply of energy and will eventually run out. On the other hand, the renewable energy sources provide hope as they are in plentiful supply, and need just to be harnessed to solve the energy crisis faced today. Ever since the fossil fuel energy availability explosion in the 19th century, the demand rate for energy has been on an exponential increase. The increased demand is depleting the energy reserves at a much faster rate than what had been previously anticipated, and this has led us today to a very crucial point in time where we have to find and tap other sources of energy if we desire to keep our lives tuned in to the same style as we're used to. The one most relevant factor and the biggest contributor to this energy problem is the phenomenal increase in the world population, which is expected to rise even more and at an increased rate, if not at the present rate, in the future. Another reason is that we have accustomed our lifestyles according to the notion that we would always have unlimited access to freely available energy, and our current practices and economies run on the immediate and unstoppable supply of huge quantities of energy. Educational, economical, social and technological sectors all rely on this supply of energy and are designed accordingly. However, we are about to face a very serious challenge, one that will have to be fought on an international scale and would need our combined effort to overcome. The energy demands in the world are expected to rise by 1-2% every year for many decades (Physics Today 2004), and the fact that many of our energy supplies will, at this rate, deplete within an average lifespan of a human being is not helping at all. The energy supplies that we have either depend upon the amount stored as fossil fuels and other stores like nuclear fuel in the earth, or the amount of energy supplied by the sun that we can harness economically through different methods (Physics Today 2004). Both the factors have their own sets of problems, but the problems and constraints on the development of renewable energy provided by the sun directly are to be considered in this paper. Case in point is the development of renewable forms of energy in the US. Energy demands can be measured in quads (Q), where 1Q = 1015 BTU, which can be approximated to 1.06 x 1018 joules (Physics Today 2004). The energy consumption of the US forms about a quarter of the total energy consumption of the world, roughly a 100Q per year, and this consumption is expected to rise by 1.5% per year for the next many decades (Physics Today 2004). The major source of energy today in the US is the petroleum. However, given the statistics, this source of energy is fast running out and other sources like coal and nuclear power are being pulled in cover up for the demands. The alternate source of energy being tapped to overcome the problem are the solar energy based sources. The three major sources utilising the solar energy are the photovoltaic cells, biomass, and wind energy. The US receives around 22 Q per year per 4000 km2 (Physics Today 2004) of solar energy in the form of sunlight. Tidal waves are also increasing being utilised and studied as a potential means of renewable energy, but currently this method is not providing any significant energy contribution. The direct conversion of solar energy into electrical energy is done in the photovoltaic cells and is known as photo-electricity. This is the most promising form of alternate energy source. However, it has certain developmental constraints attached to it. The development of photovoltaic cells is yet a new science, and is not fully develop to form a viably mass-producing energy source to be used on a commercial scale. The technology used in the production of these cells is very sophisticated and is yet very expensive. A huge financial stability is required in installing and running the voltaic plants, and this reduces the likelihood of this form of energy to be used massively, even in the US, until a cheaper method is worked out in producing the silicon-based cells. Economically, only that method of production is viable in the industry which involves a lower cost of input and a lower budget of maintenance, as compared to its output and the net yield of energy, together with the overall percentage of contribution it has in the national supply of energy. For every method of energy production, there is a phenomenon called the investment or consumption energy. This is the energy that a energy generating plant consumes in its installation and establishment, together with the financial budget that is involved in running that plant. Once it is running, it is calculated how long the plant will have to operate before it produces as much energy as was used by it, or in equaling its investment energy. Energy plants that have a long time span of fulfilling their investment energy are not economically affordable to operate. Solar panels take around 3-7 years to match their consumption energy (Physics Today 2004), which is quite high as compared to other methods like hydroelectricity or thermal electricity. These cells and panels whereas involve a large input cost and a large cost for its maintenance and repairing from natural causes and weathering, they do not have a likewise significant energy output and have a relatively small percentage in the overall national energy contribution. The overall efficiency of solar panels is only 10-20%, as they only convert about 10-20% of the incident solar energy directly into electricity (Physics Today 2004). This output efficiency is significantly lower than that achieved in the thermal power stations where fossil fuels are used to produce electricity. According to the principle of thermodynamics, energy is always lost when it is converted from one form to another. These energy losses have to be taken into account, together with the energy losses incurred during transmission, storage and supply of energy from these plants to the industries and households, along with other energy losses occurring again at these consumption sites, before it is calculated how appropriate it is to set up solar energy panels. Given the low efficiency, a large surface area needs to be exposed to the sunlight if a sufficient quantity of energy is to be produced from the panels. It is estimated that an area around 2-4 times the size of Massachusetts needs to be set up with solar panels if about 20-25% of US energy demand has to be met (Physics Today 2004). Whereas such a large area may be available in the US for setting up these plants, there are other issues connected with this that have to be dealt with. Whenever an energy source needs to be tapped, the environmental implications associated with it have to be addressed. Such a large area covered with solar panels means that no vegetation can be cultivated on that land, and it might even be necessary to clear the existent vegetation to make land for the panels. This will destroy the natural habitat of the animals and plants of that community, exposing them to the dangers of extinction. The natural cover provided by the tress and shrubs, once stripped away, can result in sheet flooding and soil erosion, furthering the already accelerating menace of desertification. The dust bowl in the US was formed by a similar process of land-clearing, albeit for other reasons. It can also be argued that such a vast area will certainly include arable land, and that arable land can be used for agriculture and crop harvesting, which will lead to an increase in food production. Another method of capturing the sun's energy is through the harvesting and utilisation of biomass. Biomass is the term used for the crops and vegetation that are grown specifically for the production of energy, and these form a different group of crops than the agricultural group, which are planted for consumption. The biomass crops have to undergo complex industrial processes, involving much consumption of energy, before they can be made into useful forms of energy. In Brazil, for instance, crops such as wheat and barley are converted to ethanol through fermentation, and this ethanol is used as car fuel. This process is, however, quite inefficient as the total energy input is greater than the total energy output. The efficiency of this method of obtaining energy is even less than that of the solar panels. Even so, it is under quite a lot of consideration in the US as a viable energy source. Currently, the US has around 1.6 million km2 of arable land (Physics Today 2004). This area is used for producing food crop, for local consumption as well as for exportation. The biomass crops would invariably have to be grown on arable land, and this might compromise the food crop production of the country. Keeping in mind the very low efficiency of energy conversion involving biomass, around 0.02 Q of energy would be produced on a 4000km2 area (Physics Today 2004). This means that to rival the energy production capability of the solar panels, an area 100 times larger than that utilised for solar energy production would have to be developed for biomass production (Physics Today 2004). This very fact, even if other constraints like low efficiency and production rates are kept out of the discussion, poses enough problems for biomass energy production development. The human population growth rate is exploding. This means that more people would have to be fed in the near future than now. Currently, the US exports about 20% of its produced food to other countries (Physics Today 2004). This would no longer be affordable as the increased food requirement would mean the utilisation of all the food crops grown in the country. In fact, more and more arable land would have to be brought under cultivation. If biomass crops are harvested on arable land, as they would obviously would have to be, there would be a competition between land available for food production and land available for energy production. Combine it with the fact that more land would be required for the construction that would have to be done for housing the increasing population, more industries, schools and offices would have to be set up to provide social services to the people, and the environmental angle would have to be covered, too, this paints a dreary picture for the development of biomass energy. Another factor necessary for the growth of food crop is maintain the fertility of the soil. Currently, fossil fuels are used to provide the nitrogen needed to provide nitrogenous fertilisers that are administered on the crops. With fossil fuels running out, the land would become infertile much more quickly. This would mean that increased availability of land, to the degree of three to four times would have to be made to cater for the current food production (Physics Today 2004), let alone the increased food demands of the near future. Wind energy is the third main source of renewable energy extracted from the solar energy. This form of energy production is the least explored from among the three methods of utilising solar energy. However, it has been estimated that this method has the potential of providing about 3-22 Q of energy in the US (Physics Today 2004). There would be considerable energy losses, just as there were for the other two forms mentioned above, for instance, losses in the transmission, storage and conversion of energy (Physics Today 2004). The two major issues related to this method are the location constraints and the environmental hazards associated with it. Wind turbines can only be installed in areas where there is enough and constant wind supply, like in the hilly areas and the coastal regions, as opposed to the conventional thermal power stations that can be constructed anywhere and everywhere. And just like solar panels require a large service area exposed in order to produce a significant amount of power, so do the wind turbines. And here the environmental hazards come into play. The large areas of turbines all working together creates enough pressure to suck any birds flying by into the rotors. Also, the natural beauty of the landscape is ruined by hundreds of turbines constructed, blocking the view and making the area dangerous for Arial wildlife. Production of a clean, cheap, easy and plentiful energy is an issue faced by the human society as time progresses and energy demands increase. Experts and scientists all over the world are trying to find new and better ways to solve the problem, while side by side improving upon the existent energy sources. There is a crucial need to change our lifestyles from energy consuming to energy conserving and energy efficient. Works Cited Paul B. Weisz. July 2004. Physics Today: Basic Choices and Constraints on Long-Term Energy Supplies. [Online]. Physics Today. Available: http://www.physicstoday.org/vol-57/iss-7/p47.html. [16 December 2007]. Read More