|Fig. 1: BMW's Hydrogen-Powered Car. (Source: Wikimedia Commons)|
Over the past decade or so, there has been a conscious effort towards preserving the environment and reducing the anthropogenic effects on the atmosphere. One of the main areas of focus has been the vehicle. Pollution caused by the burning of gasoline is one of the leading causes of global warming. As the fuel burns, carbon dioxide and other greenhouse gases are released which accumulate and effectually trap heat within the atmosphere. The research behind the hydrogen fuel cell essentially converts oxygen with hydrogen to create water vapor and eventually electricity. The reaction between the two elements is controlled and the electrical current is captured and sent throughout the rest of the vehicle. 
There are also many tests being run to determine the efficiency of these hydrogen vehicles compared to the traditional gasoline-powered vehicles or vehicle powered by electricity. Although more testing is needed, hydrogen cars proved to have a higher thermal efficiency at lower power outputs than traditional gasoline-burning engines. Hydrogen cars did prove to emit significantly less CO2, NOx, and CO which positively impacts the atmosphere.  Hydrogen cars will also improve the immediate air quality observed by humans and have the potential of having longer ranges than electric vehicles.  There are many companies fighting to become the first to break the technology to the world market. Although Toyota seems closest to achieving this, BMW is a likely candidate as well because their cars have a higher cost to own, so the extra costs related to hydrogen power may not be a turn off. Fig.1 shows how BMW has configured their hydrogen-powered car.
At surface level, the benefits of switching to Hydrogen seem to validate a push towards full implementation, but there are some hurdles that need to be addressed first. The first hurdle is the primary driving factor behind the fuel switch: environmental impact. Primarily due to the lack of complete understanding of the hydrogen cycle, scientists are unsure of the impacts the excess of hydrogen and the emissions could have on the environment. Specifically, scientists aren't sure how the world will handle this sudden influx of hydrogen. If the technology becomes the norm and replaces all forms of oil and combustion-based power, humans will account for between four and eight times the natural emission of H2 or 60-120 million tonnes per year.  Some scientists believe the leaked hydrogen (from transporting the fuel, from fill-ups, etc.) can be absorbed into the soil and have a relatively low environmental footprint. If this process is not the naturally occurring response, the excess of hydrogen will mix with other compounds and/or could accumulate in and wear away at the ozone and moisten and cool the atmosphere.  Next, there are the logistical questions. Firstly, the primary drawback to electric vehicles is the recharging process. On long trips, stopping to charge can be cumbersome. The same issue could rear its head in the beginning stages of hydrogen vehicles. Also, the price of hydrogen fuel will likely be relatively more costly than gasoline cars. Finally, a lot of progress must be made with relation to the process of storing the fuel within the vehicle while complying with safety regulations. 
Many questions still circulate the prospect of hydrogen powered cars. While there are some logistical issues such as cost, efficiency, and storage, the main questions that need to be answered relate to the environmental impact. If replacing emission of some greenhouse gases is merely replaced by the abundance of hydrogen that also has negative impact, the eco-friendly goal is not achieved. Cal Tech professor John Eiler made a great point about the prospect of hydrogen research in that it is positive that we have the opportunity to fully understand the consequences before implementation. In the past, a technology had been introduced and then a band-aid had to be applied to make up for the drawbacks. 
© Keith Weisenberg. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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