_______________________________About Our Project
Welcome to FrostedPhysics' Webpage. We are doing a Physics Project on renewable energy, more specifically, fuel cells.
Energy deregulation is in full swing across the world and there is a rapid depletion of fossil fuels,
essential for generating energy. The excessive use of fossil fuels has caused the global warming problem to escalate.
One of the most obvious major contributors to the deteriorating situation is the 750 million
registered vehicles worldwide that emit roughly 4 billion tons of carbon dioxide each year.
There is also a need for us to explore and start looking out for alternative energy sources other than fossil fuels,
as they will run out some day. When renewable energy sources are used, the demand for fossil fuels is reduced,
hence ultimately reducing the amount of greenhouse gases emitted into the atmosphere.
On this webpage, we will be exploring hybrid cars and hydrogen cars and their effectiveness in recuding carbon dioxide emissions.
We hope this webpage raises your awareness of global warming. We also hope you will do your part to reduce global warming. :)
____________________________________Information
Tuesday, June 10, 2008
The Pros and Cons of Fuel Cells
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Welcome back! As promised, in this entry, we shall cover the pros and cons of the fuel cell technology. In case you haven’t come here for so long (we will be very, very sad if that’s the case!) and have forgotten already, we talked about fuel cells and hybrid cars in our previous entry.
Hybrid cars are a type of green vehicle which can use fuel cells for energy storage. These fuel cells, or specifically, hydrogen fuel cells, are not only pollution-free, they can also have two to three times the efficiency of traditional combustion technologies. Now, back to advantages and disadvantages!
Advantages of fuel cells
i. Environmentally Friendly
• Fuelled by pure “clean” hydrogen, fuel cells produce only pure water as exhaust.
• Even when powered by fossil fuels, they produce far less pollution than conventional technologies. No combustion, so fewer gases are released.
- Almost no sulfur oxides or nitrogen oxides are emitted
- Emissions do not include any particulate matter
• If, in the long run, fuel cells could use hydrogen produced by electrolysis powered by electricity generated from renewable sources, the environmental benefits would be even greater. In that case, the outputs of fuel cells would be electricity, heat, and water vapor (produced when the hydrogen and oxygen combine in the fuel cell)
ii. High Efficiency
• Fuel cells extract more energy from a fuel – they convert chemical energy directly into electricity without the process of combustion, which means an increase in efficiency.
• No moving parts in a fuel cell stack itself so there are no mechanical inefficiencies (compared with the Carnot Efficiency that limits normal engine efficiency).
• Heat produced in a fuel cell stack can often be used rather than wasted in cogeneration situations.
• Examples:
- Combined Heat & Power (CHP) generation
- Combined Heat, Cooling and Power (Tri-generation)
- Distributed Generation (generation of electrical power close to the electrical load)
• Provides much more electricity per unit carbon compared to conventional generators of the same size
• Many of these efficiency benefits are due to the modular nature of fuel cell design.
• Using fuel cells not only helps the environment by renewable energy resources, it also results in higher efficiency. This means that less renewable energy resources are required, compared to using more non-renewable resources.
iii. High power density
• The power density of a generating system defines how much power can be produced per unit volume
• Typical value of fuel cells is usually given in kWh / l, which are high values
• Allows fuel cells to be relatively compact source of electric power, beneficial in applications with space constraints. In a fuel cell system, the fuel cell itself is nearly dwarfed by other components of the system such as the fuel reformer and power inverter.
iv. Unlimited Runtime
• Can produce electricity and heat as long as fuel is available
v. Independence from Traditional infrastructure
• With fuel cell technologies, national grids are no longer the only way to enjoy power and heat on-demand.
• As long as there is enough fuel available, independence from traditional large-scale infrastructure can be achieved
• Environmentally-friendly nature of fuel cells + considerable scalability allows systems to be place in a very wide variety of locations.
Disadvantages of Fuel Cells
i. High cost compared to other energy systems technologies
• Cost per kilowatt of electricity generated by fuel cells would have to fall by 10% for fuel cells to become economically viable (as of April 2003)
• However simple construction, so mass production costs would be very low
ii. Durability
• Certain fuel cell components e.g. cell stack can require costly replacements every few years
A limitation in using hydrogen as a fuel in hydrogen-powered vehicles is the difficulty involved in storing it in a cost-effective and convenient manner. While it is possible to store hydrogen using metals, the resulting products often can be prohibitively expensive and cause environmental problems.
NEXT UP: Conclusion
AWW, our project is coming to an end soon! We hope that you have learnt much from our project and will do your part to help curb global warming! In our next entry, we will bring our project to a conclusion by addressing the main aims of our project
and what we have achieved. Thank you and do come back again for our final update!
This entry was compiled by all of The Frostings
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