A look at the new green fuels and how the technology can best be utilised.
Sybil Ruscoe is at a farm growing maize to produce electricity by anaerobic digestion.
Tom Heap investigates the key arguments for and against the use of biofuels.
Alice Roberts discovers the potential savings available by harnessing the power of sewage.
Dan Saladino heads to Tennessee to meet the fermentation teacher and writer Sandor Katz.
Brett Westwood reflects on wildlife changes in his local patch over 40 years.
Sheila Dillon on an ancient, mysterious yet essential food-making process - fermentation.
Sheila Dillon explores the science of maturation and transformation in food and drink.
Gaia Vince asks if we can ever run our vehicles on biofuels from algae or bacteria.