Hydrogen as a source of energy
The demand for energy has been increasing fast since the time of industrial revolution. In the modern world, energy is mainly used for transportation, communication, industries, residential (refrigeration, heating etc) and commercial purposes and generation of electricity. With the ever growing development in industrial and transportation sector, the demand for energy is continuing to increase dramatically, impacting the global environment in unpredictable ways (Agarwal, et al, 4828).
According to the Energy Information Administration (EIA), at present, the fossil fuels (coal, petroleum and natural gas) form the most important source of energy in the U. S. Fossil fuels are a product of decayed organic material such as plants and animals, over a long period of time. After fossil fuels, the next largest source of energy on the surface of earth is biomass (Agarwal, et al, 4828). Biomass is a form of renewable energy, basically comprising of all organic matter (of plant origin) present on the surface of earth, which traps solar energy through the process of photosynthesis.
These include wood, wood waste, corn, agricultural residues, crops etc (Agarwal, et al, 4828). As shown in figure 1, presently, the US economy depends primarily on fossil fuels and thus can be described as ‘fossil fuel dependent economy’. According to the statistics given by EIA, the transportation sector relies almost exclusively on liquid hydrocarbons (petroleum and its products like diesel and natural gas) as the source of energy, whereas the bulk of electricity is generated through fossil fuels.
Only about 14% of the total energy needs at present are met through sources (like: renewable sources of energy and nuclear energy) not using fossil fuels. Figure 1. U. S. Primary Energy Consumption (by Source and Sector, 2005) Source: Energy Information Administration. ” Official energy statistics from the US government: Energy Basics 101”. 2005.
Annual Energy Review. Accessed 4 May 2007 http://www. eia. doe. gov/emeu/aer/pecss_diagram. html Disadvantages associated with the use of fossil fuels Recently there has been a lot of concern regarding the unpredictable impact caused by the use of fossil fuels, on the global environment. Some disadvantages associated with use of fossil fuels as described by Brian are enumerated below:
• The main disadvantage associated with use of fossil fuels is the emission of massive quantities of carbon dioxide (CO2). As shown in figure 2, CO2 forms the major bulk of green house gases. According to US Department of energy, during the year 2005, approximately 86 percent of total U. S. green house gas emissions consisted of CO2 released from the combustion of fossil fuels.
This increase in emission of green house gases has caused a great impact on our environment and is responsible for producing global warming and climate change. Green house gases like CO2,, nitrous oxide, methane, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6)etc are capable of absorbing and emitting the infrared radiations produced by the sun, thereby causing the warming of earth’s surface and atmosphere. • Burning of fossil fuels also results in emission of gases (like carbon monoxide, nitrogen oxide, unburnt hydrocarbons etc), which can pollute the environment.
• Fossil fuels are non-renewable sources of energy, once used they cannot be re-used. Also there are fixed amount of reserves of fossil fuels available on the surface of earth; once they are used up, there will be no more available. • High cost: Most of the petroleum requirements of US have to be imported from Middle East countries. The prices of petroleum having been reaching sky-high since past few years. This has led to an economic dependence on Middle–East countries.
All the above mentioned problems have led to serious concerns over the continuing use of fossil fuels as the major source of energy. According to Pacala & Socolow (968), the atmospheric concentration of CO2 should be restricted to about 500 parts per million, in order to prevent the most damaging effect on climate change. Thus there have been serious concerns all over the world to adapt a new source of energy and save the planet against harmful effect of green house gases and environmental pollution. Increasing advancements in the field of science and technology, have help scientist focus on development of renewable sources of energy like solar energy, wind energy etc.
Among the search for options which can replace the current, fossil fuel based economy , scientists all over the world have been focusing their attention on hydrogen as an energy storage medium and have been suggesting a shift from ‘fossil fuel based economy’ to a ‘hydrogen based economy’. Figure 2. US Green House Gas Emission Source: U. S Department of Energy. ”Emissions of Greenhouse Gases in the United States: 2005”. 2006. Accessed 4 May 2007 <ftp://ftp. eia. doe. gov/pub/oiaf/1605/cdrom/pdf/ggrpt/057305. pdf> Hydrogen Based Economy
In the hydrogen based economy hydrogen would act as primary energy storage medium. Use of hydrogen as an alternative source of energy appears to be a lucrative option for scientists all over the world. In 1874, Jules Verne, recognizing the potential of hydrogen as a source of energy for future, made the comment that “water will be the coal of the future” (qtd. in Turner, 972). According to Brian, in the hydrogen economy, hydrogen would serve as a replacement of fossil fuels in achieving all the energy requirements.
Generating all the electricity, without using fossil fuels, will be the biggest change that would be seen in the hydrogen economy. At present, about 68 percent of the electricity produced in the United States comes from fossil fuels (see figure 1). In hydrogen based economy, all electricity needed, would to be supplied by renewable sources of energy. This would include solar energy, hydro-electric energy, wind energy etc. In addition to this, in hydrogen based economy, fossil fuels (especially petroleum and its products) would not be used for different modes of transportation (cars, trucks, trains, boats, planes etc).
In hydrogen based economy, hydrogen would serve as a replacement for hydrocarbon-based fuels (petroleum and its products) for different modes of transportation. Efforts are being made to convert many vehicles, from using petroleum-derived energy into using hydrogen-derived energy. Besides cars, this would include vehicles like trucks, minivans, motorcycles, buses, trains, watercraft and aircraft etc. The hydrogen would be utilized either by direct combustion in internal combustion engines or as a fuel cell (Hydrogen 2000, Inc, 29).
In internal combustion engines, hydrogen would burn in engines instead of petroleum. In fuel-cell, hydrogen is made to react with oxygen resulting in the production of water and electricity. The electricity is then used for running the vehicle and for number of other purposes as would be described later (Hydrogen 2000, Inc, 37). Fuel cells would be able to replace internal combustion engines and turbines in converting chemical energy to kinetic or electrical energy. Some of the advantages of using hydrogen as a source of energy as described by Brian are mentioned below.