You are here:  Home > Transport > Fuels > Alternative fuels
University of Bristol
Institute of Physics logo
Why not try our other site: BEEP Biology & Ethics

Alternative fuels

Mazda RX8 Hydrogen powered car

Mazda RX8 Hydrogen powered car. Click to enlarge

Alternatives to petroleum as a source of energy to power vehicles include

  • Electricity
  • Hydrogen
  • Biodiesel
  • Alcohol
  • Solar power

Hidden costs

Each of these need careful consideration as there are often hidden costs to the environment.



Whilst electric cars do not pollute when they are driven, they need to have their batteries recharged.  This uses electricity produced from a power station; most power stations are coal fired and thus emit greenhouse gases.



Whilst hydrogen cars produce only non-polluting water vapour as exhaust gases, the hydrogen they use has to be obtained somehow. This usually involves fossil fuels somewhere along the line, such as in producing the electricity to power the electrolysis of water to make hydrogen; or, more likely these days, in reformers where hydrogen is made from hydrocarbons such as methanol.



Biodiesel can be made from waste vegetable oils ( Make your own biodiesel) but the vast majority is made from palm oil. It is now becoming so popular across Europe that vast tracts of rainforest in Malaysia and Indonesia are being cleared for oil-palm plantations. This is also happening in Brazil to make space to grow the sugar cane needed for processing into ethanol for alcohol powered cars. Thus the world is losing even more rainforest, releasing carbon dioxide into the atmosphere as the land is cleared. The end result is fewer trees and green plants to take up the carbon dioxide that is already in the atmosphere.



Solar powered cars are the only completely green option but they are still at the concept stage. See the World Solar Challenge website for information on the cars in the annual 3,000 km race for vehicles powered by sunlight alone. The film Race the Sun starring Halle Berry and James Belushi tells the story of a group Hawaiian High School Advanced Level Physics students who designed, built and ran a car in this race.

Consequences of changing to an alternative fuel.

Consequence mapping helps you think through a variety of effects that may follow a change. Choose an alternative fuel from the above list and research the consequences of at least half the UK population swapping to that fuel. Draw up a concept map of all the social, ethical, environmental, economic and maybe even legal consequences that you can think of. You can find links to lots of articles in our News Archive.

Quick quiz: how much do you know about how travel choices affect the environment?

What's your opinion?

Average rating

Not yet rated

Read comments

NOT RATED ruffie 20-05-09 21:41
this is supposed to be a physics web site... what is the physics in this? where does the physics come in to play here?
NOT RATED David 21-05-09 08:47
The site is about the ethical choices that face us as we USE physics to make things in the world. The applications of science have consequences that we must look out for in advance. Cars run on the principles of physics and energy tranfer. How we obtain the energy to run them is an ethical choice.
NOT RATED Patel Archit 29-07-10 16:22
this is very useful physics site. it's a very very important of physics's lover
NOT RATED rubina 21-08-10 11:56
trvel choices effect the environment a lot.suppose we r travelling a long dist.alone by a car or bus then we alone create pollution on the earth but if we travel by plane then we can controll the pollution.

Bookmark this pagefacebook myspace bebo delicious diigo stumbleupon twitter reddit yahoo google


Hybrid cars

Read this BBC report on hybrid cars and carry out a thought experiment. Predict what will happen if hybrid cars became the most popular. Observe whether others agree with your prediction. Analyse the reasons why. Evaluate your and their conclusions, are they reliable? Realistic?

Prius screen

Toyota Prius hybrid car energy management screen
Click to enlarge.


Listen to these BBC World Service programmes on the low carbon future
Hydrogen power
25 mins each