Thursday, 31 January 2013

Energy from Waste

We must find alternatives to fossil fuels for our energy.

We must also tackle the huge amount of waste we send to landfill. Waste that is packed with energy.

An obvious solution would be to extract energy from the waste but it is never that simple.  Energy can be extracted using different technologies such as anaerobic digestion used in some material recovery facilities or direct combustion (incineration) of the waste.

EcoWarriorMe has previously commented on anaerobic digestion which produces methane gas that can be burned to produce heat, generate electricity or, in the case of CHP, both. The main criticism of this technology is that it generates demand for waste, particularly organic waste such as food.

Incineration is probably the most controversial of the technologies due to the toxins which can be emitted from the plant.  In the 1980s, controversy surrounded the waste incineration plant at Bonnybridge near Falkirk which was blamed for illness in livestock which grazed locally. This was blamed on dioxins and furans emitted by the plant however the long running court case concluded that emissions were too low to cause ill health in animals or humans. Our understanding of the harm these chemicals can cause has progressed in the twenty years since this case and the conclusions may differ if the studies were repeated.



Nevertheless, the risk to health of very small concentrations of highly toxic and carcinogenic compounds emitted from incineration of municipal waste is very real. According to SEPA, there are no safe exposure limits.

Regulations limit the emissions to fairly stringent levels, for example dioxins must form less than one tenth of a thousandth of a millionth of a gramme or 0.1 nano grammes per cubic metre (0.1 ng/m 3).  The waste management industry claims that technology has improved sufficiently to achieve these requirements but evidence of the plant in Dumfries does not support such a stance.

The Dargavel plant near Dumfries began commissioning in 2009 and after repeated problems, was closed in early 2011 for a year to allow design and installation of a new boiler system.  This did not solve all the problems and the plant had breached limits on dioxin and furan emissions on several occasions and had omitted to inform regulators on at least one occasion. An explosion at the plant is also being investigated by the Health & Safety Executive. The technology is not proven.

In addition to the dioxins, there have been 200 emission exceedances and dozens of complaints about noise and the plant has accepted waste out with permitted working hours. The amount of electricity generated is also way below expectations.

Yesterday, Glasgow City Council approved plans by Viridor for a new waste to energy incinerator at Polmadie within the city of boundary. Despite many objections to the plant located in a densely populated area the approval seemed a formality with, apparently, the local councilor being prevented from addressing the planning committee. This is not surprising considering it is a key part of the councils strategy to reduce the quantity of waste going to landfill. The council currently has the lowest recycling rate in Scotland and probably the worst of any comparable city in Europe so it plans to burn the waste instead.

The scheme locks Glasgow into generating waste for the next twenty five years to feed the plant with, we understand, financial penalties if sufficient waste is not provided thus thwarting efforts t use resources more sustainably.  It also threatens the city's already poor air quality and the health of people in one of the most sickly cities in Europe.

Glasgow - the Dear Green Place, Canditate city for European Green Capital. Just don't ask about the Zero Waste policy.

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