Turning waste into energy is nothing new. The problem is the process leaves behind a heavy carbon footprint.
But a UK company claims to have developed a new technique that turns household rubbish into clean, renewable energy by using so-called “plasma gasification”.
Waste left over after food, glass and paper have been removed is fed into a gasifier where it undergoes a high temperature chemical conversion. Oxygen is removed and the rubbish is broken down into simple molecules, which are transformed into a synthetic gas known as “syngas”.
Rolf Stein, CEO of Advanced Plasma Power, explains:
“Plasma is essentially a high-temperature electric arc. It’s an arc that’s struck a bit like lightening as a form of plasma. It’s often referred to as the fourth state of matter. It’s a highly ionised, high temperature gas and what we use that plasma for is to crack the long chain of tarry, organic molecules within a gas.”
According to its inventors, the method is more efficient than coal processing or incineration. What’s more, it can be used directly in gas engines, just like natural gas. With the advent of fuel-cell cars, syngas could become a cleaner transport alternative. And, they claim, there is another advantage:
“These components, normally, when you incinerate something, produce an ash. This ash has to be disposed of, this has problems. It contains heavy metals, it contains leachable components. The gas plasma process actually takes these ash components and converts them into a vitrified material. This material actually can be used as a product,” says Richard Taylor, technical director at Advanced Plasma Power.
It’s a product which they argue could be used as an aggregated inert material in the construction industry.
While its inventors believe “rubbish mining” could lead to a new form of gold rush, the technology has drawn criticism from environmental organisations such as Greenpeace. The group points out that instead of encouraging people to produce less waste, the technology does just the opposite. The heavy investments required to build the new processing plants are simply not justified, says Greenpeace.