Hydrogen And Fuel Cells Workbook

Name: Date: Class: This booklet accompanies the Fuel Cells & Hydrogen Engineering Masterclass delivered by Gavin D. J. Harper of the PURE Energy Centre on behalf of The Royal Institution of Great Britain and the Royal Academy of Engineering. Some material in this booklet has been excerpted from Gavin’s book “Fuel Cell Projects for the Evil Genius”.

© Gavin D. J. Harper 2008 – Free Photocopiable Resource

We use energy every day in our homes, vehicles and places of work. Increasingly, we are aware of the impact that our energy usage has on the environment. With increasing rates of vehicle ownership and usage, and continual growth of the use of electricity globally our demand for energy is insatiable. When we talk about ‘using’ energy, we do not really mean that we are ‘using it up’ : this is impossible. The law of ‘Conservation of Energy’ states that energy cannot be either ‘created or destroyed’; instead it is ‘converted from one form to another’. When we are travelling in a car, the chemical energy stored in the hydrocarbon bonds of our petrol or diesel vehicles, is converted to heat energy as the fuel burns. The expansion that results from this release of heat energy, pushes a piston along a cylinder – so the heat energy is converted to kinetic energy (motion). The linear motion of the pistons is converted to rotary motion, and through the gearbox and transmission, the car moves forward. The car uses hydrocarbon fuel, and produces carbon dioxide and other emissions from burning this fuel. In the home, when we use electricity, we are often unaware of the complex series of energy‐conversion processes that take place in order to deliver this electricity to our door. In a fossil fuel power station, fuel is burned to produce heat, which is in turn used to produce steam. This steam is used to turn a turbine, which in turn is coupled to a generator to produce electricity – which is then transmitted through a network of cables to our homes, offices, factories, schools and anywhere else where we use electrical power. Thermal generation of power, comes with drawbacks – when we burn fossil fuels, we produce vast amounts of carbon dioxide, and other emissions that come as a result of burning fuel. Also a lot of heat is wasted up cooling towers. In a nuclear power plant, the process of nuclear fission is used to produce heat instead of burning fuel.With nuclear power, whilst no carbon dioxide emissions are produced at the point of generation, we need fossil fuels to power the complex process of nuclear fuel extraction and processing. In addition to this, nuclear power stations leave a legacy of radioactive waste which we still have no permanent solution to. Renewable energy, by contrast, produces no emissions or toxic wastes – it is clean and always available for free. We can take renewable energy and produce hydrogen by a process called ‘electrolysis’ allowing us to “store” energy. This is particularly helpful as it means energy can be transported. Also renewable energy isn’t always “there” when you want it as the wind doesn’t always blow and the sun doesn’t always shine. Storing the energy can help us compensate for this intermittency.

The Fuel Cell is not a new concept. The  first fuel cell was developed in 1845 by  the Welsh scientist Sir William Robert  Grove. A fuel cell converts chemical energy to  electrical energy using the process of  catalysis. Remember! Catalysts are not used or consumed  in a reaction – a catalyst increases  the rate of a chemical reaction. 

Diagram of Grove’s Original Fuel Cell

In a fuel cell, ‘platinum’ (which is very expensive) is used as a catalyst  ‐ however, this makes fuel cells expensive to manufacture. Scientists are trying to reduce the amount of platinum in fuel cells and look for alternative materials that are less expensive.

In this ‘Engineering Masterclass’ we will be using a type of Fuel Cell called a  ‘Proton Exchange Membrane’ fuel cell, sometimes also known as a ‘Polymer  Electrolyte Membrane’ fuel cell. This is one of a ‘family’ of different fuel cells. PEM fuel cells operate at low temperatures and pressures.

A f…… c…… takes h………… and using a p……….. c………. the  hydrogen atoms are split into p……….. and e……….. The p………… pass through the m……….. which is made of a  special plastic called N………. . Meanwhile, the e……….. Flow  around the circuit doing useful work. At the other side of the membrane, the p…………, e…………  and o………… combine to produce the only waste product of  a fuel cell – pure w……. .

We can produce hydrogen from  fossil fuels, using a process called  steam reformation – however,  this produces the greenhouse gas  c………… d……….. as a by‐product. A cleaner way to produce  hydrogen is using a process called  e………………… where electricity  produced from r……………….  energy sources, is used to split  water into its elemental  components h…………….. and  o……………. .

In our fuel cell vehicle, energy conversion processes are  taking place, transforming the hydrogen into movement of  the vehicle. (Ignoring the flashing lights at the moment) – the fuel cell converts “C” energy into “E” energy. The “E”  energy travels through the wires to the motor, which  converts “E” energy into “K” energy.

C……………

E …………

K…………..

ACROSS 1 Chemical symbol for Water 6 Catalyst. 8 Energy that is clean and sustainable. 9 Chemical symbol for Carbon Dioxide 11 A fuel cell combines this element  with hydrogen to make water. 12 ___ of Hydrogen is one of the  challenges that must be solved before  hydrogen vehicles become a practical  reality.

DOWN 1 Lightest gas 2  Chemical symbol for pure oxygen  molecule. 3  Electrochemical energy conversion  device 4  A fuel cell's useful product (1) 5 Fuel cell's emissions. 7  Plastic used in PEM membranes 10 A fuel cell's useful product (2) 

http://www.howstuffworks.com/fuel‐cell.htm http://auto.howstuffworks.com/fuel‐cell‐quiz.htm http://www.fuelcells.org/ced/education.html http://www.fuelcells.org/ced/education.html#stud http://www.hydrogensociety.net/Hydrogen%20for%20Kids.htm http://www.kids4hydrogen.com/ http://www.lshc.co.uk/ http://www.lshc.co.uk/secondary/lessons_infosheets.asp http://www1.eere.energy.gov/hydrogenandfuelcells/ http://www.shell.com/home/content/hydrogen‐en/faq/fuel_cell_1204.html http://www.h2fcfuture.gc.ca/en/index‐e.html http://videos.howstuffworks.com/ballard/651‐ballard‐shows‐how‐a‐fuel‐cell‐works‐video.htm

•Paperback: 196 pages  •Publisher: McGraw‐Hill/TAB Electronics  •Language: English  •ISBN‐10: 0071496599  •ISBN‐13: 978‐0071496599  You can find more experiments with Fuel Cells, information about clean energy  and information about how to take the learning in today’s  masterclass forward in ‘Fuel Cells Projects for the Evil Genius’.