英語學習點: Renewable Energy 再生能源

With revenue from pig products getting smaller every year, some farmers from rural England have decided to make some extra money by turning poo into profit.

James Hart, who runs a pig farm, came up with a simple solution of using the huge amount of pig faeces, cow dung and chicken droppings on his farm to generate electricity.

It may look unremarkable from the outside, but inside Glebe Farm there is a state-of-the-art biogas station. It's one of only a few in the UK, which has been slower than many of its European neighbours in developing renewable energies such as wind turbines and solar panels.

So how does it work? Large quantities of animal waste are mixed with lots of grass in a tower. Bacteria then break it all down, producing methane, which is siphoned off, cleaned and filtered.

The gas is then used to power an engine which in turn powers a generator. The electricity from this is then fed into the National Grid. Mr Hart thinks he'll be able to sell 2.2 million kilowatt hours of electricity every year.

The heat generated by the process is also captured and used for central heating at the farmhouse.

But it's not only Glebe Farm which benefits. Methane is one of the most powerful greenhouse gases - 20 times worse than carbon dioxide in trapping heat in the atmosphere. By capturing so much of it, Mr Hart expects to reduce his carbon footprint by about 10,000 tonnes a year.

James Hart says he's pleased because he's managed to find another source of income and improve his environmental impact.