Secondly, the municipal wastes burned often generate harmful emissions and foul odours. Finally, Heinberg claimed that the energy needed for biomass conversion is more than the biomass-derived fuels release when burning8. In other words, the net energy of biomass conversion could be considered zero. Nuclear power is a popular way of generating energy, which will most probably come into more common use in the future. Nuclear fission, involving the splitting of uranium-235 into smaller elements and releasing large amounts of energy, has been used in power plants since 1954.
One tonne of the nuclear fuel, Uranium, can produce the same amount of electricity as 150,000 tonnes of coal. About 15 percent of the world’s electricity comes from nuclear power. Some countries, such as France and Japan, are heavily dependent upon it. Indeed the government of the United Kingdom plan to implement new nuclear power stations by 20209. However the process suffers many drawbacks including the production of radioactive waste which must then be disposed. The waste remains radioactive for thousands of years and exposure can cause damage to cells as radiation sickness, cancer, and eventually death.
There is also the risk of meltdown should the reactor become unstable, as in 1986 Chernobyl, Ukraine which resulted in multiple deaths and with the region still inhabitable. These factors have led to poor public opinion of fission, and whilst many hundreds of reactors around the world remain functional, the construction of new reactors has slowed to a virtual standstill since Chernobyl. The supply for uranium will not last forever, either. HYDROGEN – AN ALTERNATIVE FUEL? HYDROGEN NUCLEAR FUSION Hydrogen comprises nearly 80% of all matter in the universe.
Hydrogen nuclear fusion is a process where two lighter atomic nuclei fuse, forming a heavier nucleus and releasing energy10. The type of nuclear fusion currently being researched most vigorously in the context of forming a future source of power is the fusion of two isotopes of hydrogen – deuterium and tritium, forming helium and a neutron and releasing large amounts of energy. This process yields 17. 6 MeV11 per fusion. A central concept in understanding the origin of this extra energy is the equivalence of mass and energy.
Energy is released due to a difference in mass between the helium atom compared with the sum of the Hydrogen atoms, therefore some mass is converted into energy via Einstein’s relationship of E=mc2; where E=Energy, m=mass of nuclei, and c=speed of light (3×108). The strong nuclear force binds together protons and neutrons in the nucleus, as it is very strong over short distances it overcomes the electromagnetic repulsion of protons in the nucleus. The energy that is required to hold the nucleus together can be thought of as adding to its mass.
Hence the mass of a deuterium nucleus is higher than the mass of its individual components when isolated therefore energy is released when they are taken apart. The total mass of the deuterium and the tritium nuclei before the reaction is more than that of the helium nucleus and neutron formed. This is because the neutron that is emitted is no longer held by the strong nuclear force, the forces have been rearranged at the end of the reaction ending up with a lower potential energy. This energy that once held the neutron is carried away as translational kinetic energy, which does not affect the particles’ mass, largely by the neutron.
The typical values of this extra kinetic energy are 14. 1 MeV on the neutron, 3. 5 MeV on the helium. However the energy required for this to occur is staggeringly high, and the deuterium and tritium gas must be heated to such high temperatures that they form a plasma – the fourth state of matter. It is only at such high energy states that the deuterium and tritium will collide with enough energy to overcome the strong force binding the protons and neutrons together in the nucleus.
A plasma state occurs when atoms become so energetic that the nucleus and the electrons overcome the electromagnetic forces holding them together and separate and a ‘sea’ of charged particles, the negative electrons and the positive nuclei, is formed. Temperatures around and above 10-15 million Kelvin are required for fusion to occur. This is a major drawback as producing energy via fusion will not be profitable at the moment. COLD FUSION Cold fusion refers to the nuclear fusion of deuterium at near room temperature12.
In 1989, American chemists Stanley Pons and Martin Fleischmann claimed that an experiment conducted at room temperature using platinum and palladium electrodes immersed in heavy water (deuterium oxide) had produced excess heat and other byproducts that they attributed to a fusion reaction. Attempts to replicate their experiment produced conflicting results, however, research into the possibility of cold fusion continues, because of the desirability of producing fusion energy at any temperature. As of now, no model has accounted for the full range of experimental observations. FUEL CELLS
Another possibility for generating electricity is the fuel cell. A fuel cell is a device that transforms hydrogen and oxygen into electricity. Electrolysis separates water in its basic elements: hydrogen and oxygen13. A fuel cell consists of two electrodes (anode and cathode) and an electrolyte. The electrolyte functions as a partition between oxygen and hydrogen, preventing the two from direct contact. Instead, a controlled electrochemical reaction takes place and results in electric potential between the two electrodes and this can be converted directly to electrical energy.
The only by-products of this are water and heat. Pressurized hydrogen gas enters the fuel cell on the anode side and is forced through the catalyst by the pressure. When a hydrogen molecule contacts the platinum on the catalyst, it splits into two H+ ions and two electrons. The electrons are conducted through the anode, where they travel to the external circuit and return to the cathode side of the fuel cell. On the cathode side, oxygen gas is forced through the catalyst and forms two oxygen atoms.
The negative charge of these atoms attracts the two H+ ions through the membrane, where they combine with an oxygen atom and two of the electrons from the external circuit to form a water molecule. This reaction in a single fuel cell produces only about 0. 7 volts. To get this voltage up to a reasonable level, many separate fuel cells must be combined to form a fuel-cell stack14. Much scientific and technological effort is being spent on effective storage and transport system as, unfortunately, this method demands the highest cost costs.
CONCLUSION In conclusion, it can be claimed that we are heading for an energy crisis, if not in one already. Clearly, there is a foreseeable problem of how to deal with an energy crisis caused by increasing demand of energy and lack of energy supplies. Renewable energy seems a very feasible possibility, however, poor conversion efficiency is a bother. The idea of the fuel cell is very exciting and could well be the way forward in generating electricity for the future, especially if the issues of storage and transportation can be solved.
Currently, the only viable way to produce energy using nuclear power is via nuclear fission as attempts are still being made to discover ways in which to produce energy using cold fusion. If discovered, our entire energy crisis would be solved. WORD COUNT: 2,125 BIBLIOGRAPHY Williams, JL, The coming energy crisis, 2003. Leggett, J, Half Gone: Oil, Gas, Hot Air and the Global Energy Crisis, Portobello Books Ltd, 2006. Price, N, The Energy Crisis: How Do We Fuel Our Future? , Pocket Issue Limited, 2007.
Brower, M, Cool Energy: Renewable Solutions to Environmental Problems, MIT Press, Cambridge, 1992. Heinberg, R, Party’s Over: Oil, War and the Fate of Industrial Societies, New Society Publishers Ltd, Gabriolia Island, 2005. http://www. jakeg. co. uk/dissertation/peak_oil. gif www. iea. org Biomass: versatile source of energy 2000. http://www. teriin. org/energy/biomass. htm http://news. bbc. co. uk/1/hi/uk_politics/7179579. stm http://en. wikipedia. org/wiki/Nuclear_fusion en. wikipedia. org/wiki/Cold_fusion en. wikipedia. org/wiki/Fuel_cell
1 Williams, JL 2003, The coming energy crisis. Retrieved from: http://www. wtrg. com/EnergyCrisis/ 2 http://www. jakeg. co. uk/dissertation/peak_oil. gif 3 www. iea. org 4 Seitz, JL 2002, Global Issues: An Introduction, Blackwell Publishers Ltd, Oxford, p. 127 5 Heinberg, R 2005, Party’s Over: Oil, War and the Fate of Industrial Societies, New Society Publishers Ltd, Gabriolia Island, pp. 153 Retrieved December 6, 2005, from Ebrary: http://site. ebrary. com/lib/uon/ 6 Biomass: versatile source of energy 2000. Retrieved December 4, 2005, from: http://www.
teriin. org/energy/biomass. htm 7 Brower, M 1992, Cool Energy: Renewable Solutions to Environmental Problems, MIT Press, Cambridge. 8 Heinberg, R 2005, Party’s Over: Oil, War and the Fate of Industrial Societies, New Society Publishers Ltd, Gabriolia Island, p. 173 9 http://news. bbc. co. uk/1/hi/uk_politics/7179579. stm 10 http://en. wikipedia. org/wiki/Nuclear_fusion 11 megaelectron volt = 1. 60217646 i?? 10-13 joules 12 en. wikipedia. org/wiki/Cold_fusion 13 en. wikipedia. org/wiki/Fuel_cell 14 http://www. howstuffworks. com/fuel-cell. htm