Sunday, October 14, 2007

Do You Agree With Cardiff University's Assessment of the Potential AD Renewables Contribution?

Cardiff Univerity's Waste Research spin-off has a page which is vying with for its place in the first page of the Google SERPS results. Sometimes our site is just above them and on other days it is a listing or two below.

The page to which Google sends us to at Wasteresearch contains in my view really quite a negative and disencouraging analysis of the potential of Anaerobic Digestion to become a significant player in the renewable energy scene.

Here is the paragraph to which I refer:-

An analysis can be conducted for anaerobic digestion in a similar manner to the previously used technique to estimate the potential of generating electricity by using all the UK's available waste. There is about 90Mt of waste produced in the UK each year. 62% of this waste stream is said to be biodegradable (DETR, Limiting Landfill, 1999). This biodegradable waste will produce about 150m3/tonne of biogas at 60% methane concentration (Warmer Information Sheet, 1998). Using a 70% process efficiency, 70% load factor, and the known 37GJ/tonne energy content for methane, an estimate can be produced. After accounting for the 20-40% of energy needed to maintain the digestion is accounted for, anaerobic digestion could provide the UK with about 1.4GW. This represents about 1.9% of the UK's installed capacity.

It is really good to see people carrying out a reality check on Anaerobic Digestion, but I wonder if this data does not underestimate the amount of waste produced in the UK currently if all industrial and commercial waste is included? I also suspect that the compounding of percentages is excessively reducing power output.

There is no mention of combined heat and power (CHP) use, which when included in projects, ups the efficiency greatly.

There is also no comment here on the benefits of AD in providing local power close where it is consumed, meaning vastly reduced distribution losses in the power grid, or potentially from the products of AD when markets are found.

I believe that HAASE for example produce an RDF from the dried residual fibrous material (Luebeck Plant), and I am sure that factors like this are begining to alter the picture painted by Wasteresearch, as AD technology advances

So, if as I suspect we have some regular readers of this blog who are knowledgeable about such things, here is your challenge to email us at with your comments in a form in which we can publish them, or use the blog commenting system, and stand up for AD!

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