There’s something in the wind…

Amidst all the excitement of “Particulart: Up in the Air”, let’s not forget our origins, critiquing the Incinerator. In the 16th July edition of Express & Echo, there was a short update on Recycling in Exeter.

2015-07-16 E&E p44

Diana and I couldn’t let this pass. I was particularly struck by the nonsensical “contributing 3MWh per hour of operation to the National Grid”… which just means the Incinerator’s generation capacity is 3MWe, and tells us nothing about the number of hours of operation and how much electricity it has actually generated. Diana is currently trying to get hold of some data for generation and operating costs. In the meantime, I have compared it with the capacity and cost of wind generation.

OK, so according to its communications, the Incinerator was expected to cost £45m, and has a capacity of 3MWe. That’s £15m per MWe. The cost of generating each kWh is to be determined.

Let’s take offshore wind, which the UK is quite good at. Each turbine in the London Array, commissioned in 2012, has a capacity of 3.6MWe. At the moment, the average cost of capacity is 2.5-3.0 million Euro/MW, or up to £2m per MWe; and the average cost of generation is 161 euros ($208) per MegaWattHour, or 11p/kWh.

So the Incinerator has a smaller capacity than one wind turbine, and costed 7.5 times as much per MW!!

Here’s the Incinerator equation for garbage in, garbage out:

(carbon content of waste + rest of waste) + oxygen + other reactive gases
   → carbon dioxide + other flue gases + flyash

Some estimate the carbon content to be 27% of the total waste, which means that incineration of 1 tonne of waste would produce approximately 1 tonne of carbon dioxide. Others put the carbon content at nearly 50%, which means 1 tonne of waste in, nearly 2 tonnes of carbon dioxide out.

The Incinerator is designed to accept up to 60,000 tonnes per year of waste. That means 60,000 to 120,000 tonnes of carbon dioxide emissions every year. Exeter has a population of about 120,000. Ignoring the carbon footprint of building the Incinerator and offshore wind, and of other operations such as waste delivery, flyash removal and maintenance…

The Incinerator adds 0.5 to 1 tonnes of carbon dioxide to every person’s annual carbon budget. Offshore wind is zero carbon.

Furthermore, that is 60,000 tonnes of waste that has not been reduced, reused or recycled. It is not very surprising that recycling rates in Exeter have gone down, since the Incinerator needs feeding.

Now let’s turn to Diana’s main concern…

Food waste makes up about 36% of the waste input to the Incinerator, and it could instead be be composted or processed more efficiently in a anaerobic digester to produce biogas. The point about the garden waste scheme is not relevant regarding food waste, as the scheme really does only collect garden waste.

Diana thinks the point about the cost of food waste collection is a cover up for the fact that Exeter City Council’s negotiations with Teignbridge and East Devon District Councils on food waste collection have recently collapsed.

Here’s another article from Monday’s Express & Echo, which makes the arguments over the cost of collection academic.

2015-07-20 E&E p7

So if food waste is rightly diverted away from the Incinerator, where will all the waste to feed it be sourced?


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