Fuel cells and biofuels
This list provides resources which explore the use of biofuels and hydrogen fuel cells as an alternative to fossil fuels.
Hydrogen is considered a ‘clean’ fuel compared with carbon-based fuels such as petrol or diesel because only water is produced. Hydrogen fuel cells are especially appealing in urban areas, where electric buses and cars that run on fuel cell power are becoming gradually more common..
There are ethical issues surrounding the use of biofuels which can be used as topics of discussion with students. For example, the use of crops that could be used to feed people being used to provide the raw materials for biofuels - students could discuss how this could cause food shortages or an increase in the price of food.
Other economic issues surrounding the use of biofuels include:
Human resources - more people are needed to produce biofuels than are needed to produce petrol and diesel
Increased income - for farmers
Lower fuel prices - biofuels limit the demand for fossil fuels, helping to reduce increases in fuel prices.
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.
Links and Resources
This resource describes two methods for making a hydrogen-oxygen fuel cell.
One approach to teaching about fuel cells is to carry out various demonstrations of how hydrogen reacts with oxygen, how water is electrolysed and how cells (batteries) work.
It may be useful to start with the standard test for hydrogen, or Exploding balloons.
You could make a hydrogen rocket for another spectacular demonstration of the explosive power of these gases. Or take the flaming hands demonstration one step further with this demonstration from the Christmas Lectures.
This resource describes the electrolysis of water with a twist - the evolving gasses are used to create bubbles which will explode!
Then ask the students to use what they have learned from the demos to come up with ideas about how a gas battery (or fuel cell) might work and what reactions would need to take place. As an extension they can apply this to explain applications such as powering cars and the space shuttle.
There have been many news reports about the fact that fossils fuels are a non-renewable resource and that alternative fuels are needed for when fossil fuels run out. This article can be used to introduce students to research that is being carried out to find and make alternative fuels.
Students can use models and bond energy calculations to explore the energy changes of reacting hydrogen and oxygen together to form water. They can also carry out these calculations to compare the amount of energy released with other fuels.
Alternatively, students can carry out research into the development of renewable fuels and evaluate their benefits and limitations.
As a follow up activity, students can research different car companies’ developments in fuel cells - for example, General Motors, Toyota, Ford, BMW. They can compare petrol, hybrid and fuel cell cars and stage a role play debate, taking on the viewpoints of different interest groups. A full outline of this activity is given in the Unit 3 on fuel cells in the Royal Society of Chemistry's Contemporary chemistry for schools and colleges.
Students can find data on emissions and fuels for most makes and models of car on the VCA website.
The Greener Industry website includes a section on greener cars
This SEP resource provides a wide range of practical activities that can be used with students. It is also provides background information to share with students whilst they are carrying out their independent research activities.
Acivities that are particularly relevant to this topic are:
A2: Making biodiesel
A7: Energy released when fuels burn - to compare energy values of fossil and biofuels.
A9: Fueling a car - this may be useful as an additional resource for the previous activity on hydrogen-powered cars.
These practical activities could be used as an alternative to the SEP resources above. The resource includes information on a wide range of biofuel uses and their sustainability which could be used by students for research purposes.
It includes a variety of activities on current biofuels, which are similar to the ones described in the SEP booklet but, in addition, this resource looks at more advanced biofuels. Most of these activities are suitable for GCSE level but a few (like the bacterial and lignocelluloses) are only appropriate for post-16 students. The production of algal biofuels (pages 79 to 87) would provide an opportunity to experience some of the newest technologies being developed.
These podcasts are a useful starter activity for any lesson on biofuels. They can be used to introduce the topic as a whole or specific parts of it - for example, production and uses of biofuels. They can also be used directly by students who are doing independent research. Alternatively they could be used as a whole class activity to develop listening skills. This resource from the Science Enhancement Programme is useful for planning the listening so that meaningful learning takes place
A major area of research being carried out explores how to extract hydrogen from alkanes or methanol without using much energy, but this is still reliant on having available fossil fuels. This can be explored further by students.
With regard to fuel cells, an important point to get across is that oxygen and hydrogen may come from electrolysis of water but this may need energy from fossil fuels to start with. Solar power could be used as an alternative to electrolyse the water.
Here's another set of podcasts which explore alternative fuels.
One area of interest discussed is the storage and transportation of liquid hydrogen and oxygen used in the fuel cells. They can be stored as compressed or liquefied gases but there are issues here which need to be taken into account, particularly with the space shuttle.
Research into hydrogen storage using nanotechnology such as carbon nanotubes is under way, as is research into chemical storage using metal hydrides.
This resource can be used as a whole class discussion activity, rather than a formal debate. There are links to arguments for and against and students should be encouraged to look at all the information presented so that they can be prepared for counter-arguments.
It may be worthwhile talking to students about the background to the development of fuel cells as this could be used to develop their arguments. They were actually invented back in the 1830s, long before cars came onto the road. NASA scientists developed them in the 1950s to use on the Apollo missions and in the space shuttle. The water produced is used for astronauts on the shuttle (this is an interesting cross-curricular link to the water module).
An alternative activity could be the upd8 activity called Pump Wars in which students compare fuel choices.
This is an alternative debating activity to the one mentioned above. It can be used to form a conclusion to the research activities carried out by the students and provides is a way of assessing the knowledge they have gained without requiring a formal test.