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Thursday, January 9, 2014

How to get energy from waste

Energy biporducts can be recylced for added utility
Composting trash saves money on fertilizer and encourages plant growth

It is no secret that the human population have, and continue to be, extremely wasteful. Whilst countries in the developed world run out of landfill space for the daily waste they produce, some have begun to ship overseas; with the world population approaching 7 billion, it is now more important than ever, to harness energy from waste.

Getting energy from waste at home

Start composting

You can do your bit for the planet without even leaving your own home. Organic waste from your food matter can be transformed into fertiliser with the help of a compost bin; and given that the UK throws away on average 40% of the total food purchased (including up to a third of fresh food items) the need to dispose of food waste responsible is vital. Additionally many scientists have recognised that the amount of methane that rotting food produces can be utilised as food; indeed, this is harnessed from some landfill sites. Staggeringly, this form of energy could one day account for 1.9% of the UK’s energy needs.

 Waste heat to electricity

Since the industrialisation, the amazing amount of heat produced during many factory processes has always appeared to be a necessary waste. However this may be changing. In a relatively new project, the ways in which heat is wasted are being explored, with a view to harnessing it as an energy thanks to new technologies which will make energy waste management more productive over the coming years.

Waste energy and water into hydrogen fuel

Over the past decade, scientists have focussed upon finding alternative ways to harness energy from places that previously remained untapped. The UK has seen the introduction of solar panels and wind farms, as well as the lesser known methods of transferring energy from the waterways and seas. Currently scientists are exploring the wasted energy that is created from noise and random vibrations. This is based upon a scientific concept known as the piezoelectric effect; and it will entail the harnessing of electricity that is produced when materials are under mechanical stress.


The unharnessed power of waste is demonstrated by the fact that Norway, as an extremely efficient country, is actually importing waste from other European countries, simply to incinerate it. This will make for surprising reading to those that know about the large stocks of oil on which Norway sits. The figures make for interesting reading, as the UK actually paid for the export of 45,000 tonnes of waste to Norway; so the country benefitted not only from a monetary payment, but from the copious amounts of harnessed waste energy.

Pyrolysis and gasification

Pyrolysis and Gasification (P&G) are two slightly different processes of producing energy from waste via either an oxygen free (pyrolysis) or a limited oxygen (gasification) environment; the former of which produces an oil (known as ‘char’) and the latter of which produces gas. Pyrolysis and Gasification are employed as they are known to be far more effective than the alternative: incineration (anywhere up to 35% more effective); and can account for up to 9% of the UK’s energy needs.

About the author: Mohammed is an electrical engineer who takes his home with him. He loves tinkering with machines and finding new ways to use old items. Gardening is his second passion and he loves to combine the two to help maintain his beautiful chrysanthemums.

Image license: Infrogmation, GFDL