Abandoning fossil fuels
Owing to an increasing world population and demands for higher standards of living and better air quality, the future energy demand is expected to increase significantly. To meet this demand poses great challenges. Currently, most of the world energy requirement for transportation and heating is derived from petroleum or natural gas. These two fuels are generally favored due to the ease of transportation of liquid or gaseous forms. Unfortunately, the combustion of hydrocarbon fuels for transportation and heating contributes over half of all greenhouse gas emissions and a large fraction of air pollutant emissions. Hence, the world is currently facing urgency in developing other fuels that will cause less greenhouse gases emissions. Hydrogen fuel is the best energy alternative as it has the best potential and causes negligible emission of greenhouse gases.
For the past 40 years, environmentalists and several industrial organizations have promoted hydrogen fuel as the solution to the problems of air pollution and global warming (Sorensen, 8). The main gauges for the best fuel are inexhaustibility, convenience, independence from external control, and cleanliness. Hydrogen possesses all these properties, and is being evaluated and promoted worldwide as an environmentally benign replacement for gasoline, heating oil, natural gas, and other fuels in both transportation and non-transportation applications.
Similar to electricity, hydrogen is a high-quality energy carrier, which can be used with a high efficiency and zero or near-zero emissions at the point of use (Sorensen, 249). It has been technically demonstrated that hydrogen can be used for transportation, heating, and power generation, and could replace current fuels in all their present uses. Hydrogen can be produced using a variety of starting materials, derived from both renewable and non-renewable sources, through many different process routes. At present, two basic process technologies-reformation of natural gas and electrolysis of water are widely used. Considering hydrogen produced from renewable energy such as wind power and taking efficiency of electrolysis plants as being 85%, this also leads to an overall primary energy for a fuel cell vehicle, but this time without the emission of pollutants.
In the beginning of hydrogen economy, the principal focus of hydrogen technology has shifted to the safe and affordable utilization of hydrogen as an alternative fuel based on seamless integration of generation, distribution and storage technologies. Hydrogen is highly flammable over a wide range of temperature and concentration. Although its combustion efficiency is truly outstanding and welcomed as a fuel of the future, it inevitably renders several non-trivial technological challenges, such as safety in production, storage and transportation. Unlike ready for fuel use coal or hydrocarbons, hydrogen is not available on the earth. It is however, available as chemical compounds of oxygen and carbon. For example, hydrogen is present in water; fossil hydrocarbons such as coal, petroleum, natural gas; and biomass such as carbohydrates, protein and cellulose. Hydrogen has both similarities and differences when compared to fossil fuels.
Hydrogen has the highest energy content per unit mass of any fuel. On a weight basis, hydrogen has nearly three times the energy content of gasoline. One attractive feature of hydrogen is its electrochemical property, which can be utilized in a fuel cell. At present, hydrogen fuel cells are available operating at an efficiency of 50-60% with a lifetime of up to 3000h (Williams, 11). Owing to the high diffusivity, low viscosity, and unique chemical nature, combustibility of hydrogen is somewhat different than the other fuels. The final combustion temperature is generally lower with hydrogen fuel than with gasoline reducing the amount of pollutants, such as nitrogen oxides, emitted in the exhaust.
Hydrogen fuel is hydrogen gas with small amounts of oxygen and other materials added. Benefits of using hydrogen fuel include clean air, cleaner water and better health (Sheffield and cigdem, 40). Hydrogen is also a renewable source of energy unlike fossil fuels. Hydrogen has many properties that make it ideal as a fuel for internal combustion engines in automobiles. The main product when hydrogen is burned is water. Global warming caused by greenhouse gases is a significant problem. Therefore, the advantage of hydrogen is that CO2 is not produced when hydrogen is burned. Carbon (iv) oxide is the man product when fossil fuels are burned (Williams, 11). Hydrogen combustion does not produce toxic product such as hydrocarbons, carbon (ii) oxide, oxides of sulfur, organic acids and carbon (iv) oxide. By using hydrogen fuels, acid rain and the carbon (iv) oxide greenhouse effect could effectively be eliminated.
Hydrogen has a high flame speed, wide flammability limits and a high detonation temperature with lean burning, which give improved engine efficiency. Hydrogen is a gas; therefore there is no problem in starting the engine at the coldest winter temperatures. As with any gasoline engine, efficiency depends on driving conditions. At freeway speed, the hydrogen engine has demonstrated at least 20% increase in efficiency (Dermibas, 75). Hydrogen engines demonstrate the efficient operations of a gasoline motor. Apart from reducing the depletion of the ozone layer, hydrogen fuels are also efficient in terms of ignition speed. Hydrogen can advantageously be used in internal combustion engines (ICE) as an additive to hydrocarbon fuels.
The combustion of fossil fuels account for a majority of greenhouse gas emissions. Currently, fossil fuel combustion produces 7 Gtn/year carbon emissions and in a no-change scenario, C02 emissions in 2050 can be expected to reach 14 Gtn/year of carbon (Dermibas, 147). There is a growing recognition that steps to reduce greenhouse gases are needed, and many countries are adopting policies to limit CO2 emissions. Hydrogen, when produced from reforming natural gas, petroleum or coal, generates CO2 as a by-product. In the current processes, CO2 has been released into the atmosphere. Many countries and multi-national corporations are looking into use of energy that releases the least amount of hydrogen in the atmosphere. Hydrogen is the solution to this problem as it provides fast and efficient energy while releasing little or no CO2 into the atmosphere.
Hydrogen energy is a promising alternative solution because it is clean and environmentally safe. It also produces negligible levels of greenhouse gases and other pollutants when compared with fossil fuel energy sources they replace. Hydrogen can be obtained by direct electrolysis, direct thermal conversion, thermochemically, photochemically, photoelectrochemically and biochemically from water. Hydrogen has the potential to be an attractive alternative energy carrier for future fuel needs. The use of hydrogen as a fuel requires development in several industry segments including production, delivery, storage and end use. Burning of fossil fuels continues to deplete the ozone layer. As a result, alternative sources of energy should be used. Hydrogen is one such source of energy that causes negligible environmental degradation. Hydrogen is also a renewable source of energy unlike fossil fuels. To prevent global warming, depletion of the ozone layer, hydrogen should be used to power things around the world from cars to domestic and industrial lighting.
Demirbas, Ayhan. Biohydrogen: For Future Engine Fuel Demands. London: Springer, 2009. Print.
Sheffield, John W, and Çiğdem Sheffield. Assessment of Hydrogen Energy for Sustainable Development. Dordrecht, Netherlands: Springer, 2007. Print.
Sørensen, Bent. Hydrogen and Fuel Cells: Emerging Technologies and Applications. Oxford: Academic Press, 2012. Print.
Williams, L O. An End to Global Warming. Oxford: Pergamon Press, 2002. Print.