Integrated Physical Sciences, Essay Example

Introduction

This paper examines energy sources and the interchangeability of energy. In particular that of hydrogen as a possible alternative to fossil fuels, thereby reducing the US dependency upon fossil based fuels. The paper answers the question: Is hydrogen a serious contender to improve the US Energy situation and a viable replacement for fossil fuels?

The question of hydrogen

Hydrogen has been considered as one of the main alternative fuels to that of oil.  There are two main advantages in supporting this claim. (1) It is a renewable source of energy and (2) It is one of the most abundant elements on our planet.  Free hydrogen (F2) comprises more than 75% of our environment and particularly in water where it exists as (H2O). In water Hydrogen is 11.2% by weight or part and must be separated to free hydrogen (F2).  Hydrogen may also be collected by biomass from plants.  “However, while hydrogen offers many benefits, there are two drawbacks to using it as a fuel with current technology. Liquid hydrogen, the preferred form of hydrogen, requires four times the storage space of conventional petroleum-based fuels. The other problem is that hydrogen production depends on the availability of a non-renewable resource, petroleum. Currently, hydrogen is produced from raw petroleum for industrial use, but petroleum supplies may become limited in the near future.” (Kushnir).

Laws of thermodynamics

The first law:  Energy cannot be created or destroyed; hence that which is lost in the steady state process cannot be greater than the amount of energy gained.  This relates to the process of heat and transfer mechanism.  This might be expressed in the equation illustrated to the right.

The second law:  The basic concept relates to the spontaneous natural process of the element and the creation of an increase in entropy overall. As such heat can flow from a higher temperature region to that of a lower region but not vice versa.  Hence the way hydrogen is consumed or burned might violate the first or second laws of thermodynamics.

The problems of hydrogen

The use of Hydrogen as a serious option for fossil fuel replacement comes with a considerable number of drawbacks, for example: (i) “Perhaps the largest problem for hydrogen fuel cell transportation is the size of the fuel tanks. In gaseous form, a volume of 238,000 litres of hydrogen gas is necessary to replace the energy capacity of 20 gallons of gasoline.” (Roman).  (ii) In addition Hydrogen is highly combustible and even if you could find a means of compressing the gas, say to the size of a car tank, it would be the equivalent of travelling around on a bomb.  A crash could result in a huge explosion and tremendous loss of life “compressed hydrogen will not give a car as useful a range as gasoline. Moreover, a compressed hydrogen fuel tank would be at risk of developing pressure leaks either through accidents or through normal wear, and such leaks could result in explosions.” (Roman). (iii) It might be possible to convert the hydrogen to metal hydrides which might solve the storage problem but create a very heavy storage tank.  (iv) There is a chemical problem yet to be resolved and that relates to the extraction of hydrogen from water. At the moment this would require vast heat energy supplies and would not be a profitable situation.  Future innovation may come from energy transmission stations on the moon and transmitting solar energy to the earth in the term of microwaves. At the moment this still remains stuff of science fantasy “this reaction, 2H2O + e = 2H2(g) + O2(g), requires a substantial energy investment per unit of water (286kJ per mole).  This energy investment is required by elementary principles of chemistry and can never be reduced.” (Roman).

(iv) Because the extraction currently requires the use of fossil fuels as a source of energy it becomes a relatively self-defeating and non-viable proposition. “Because of the second law of thermodynamics, hydrogen fuel cells will always have a bad EROEI. If fossil fuels are used to generate the hydrogen, either through the Methane-Steam method or through Electrolysis of Water, there will be no advantage over using the fossil fuels directly” (Roman).

Conclusions

There is no doubt that the commercial world is extremely attractive to the use of Hydrogen as an alternate fuel.  The Space Shuttle has been using this form of fuel for years.  Not only is it in abundant supply but it is a clean energy with virtually no pollution.  At the moment the science is not quiet there in terms of commercial viability and mass production. Hydrogen is high in energy, yet an engine that burns pure hydrogen produces almost no pollution. NASA has used liquid hydrogen since the 1970s to propel the space shuttle into orbit. Hydrogen fuel cells produce a clean by-product: pure water. Hydrogen fuel alternative: nothing can compare.” (Alternative Energy Sources).

It is most likely that the science will ultimately make Hydrogen a viable source of clean energy production and as such this is just a question of time.  The need to make it a relatively safe fuel for automobiles will become very high on the agenda.  We have all witnessed what a hydrogen explosion looks like when the space shuttle blew up on take-off. The concept of a motorway pile up with cars full of compressed hydrogen gas tanks does not even bear thinking of.  However, the attractions of its abundant supply, its clean energy draw and lack of pollutants will continue science to research this as a viable commercial source of energy.

Works Cited

Alternative Energy Sources. Alternative Energy Sources. 2010. 13 10 2010 <http://www.alternative-energy-resources.net/hydrogenfuelalternative.html>.

Kushnir, Peter. Hydrogen As an Alternative Fuel . 2010. 13 10 2010 <http://www.almc.army.mil/alog/issues/MayJun00/MS492.htm>.

Roman, Joseph J. The Hype About Hydrogen . 2010. 13 11 2010 <http://culturechange.org/hydrogen.htm>.