Anaerobic Digestion-Govt is for it, but what is it?

Discussion in 'Current Affairs, News and Analysis' started by HectortheInspector, May 13, 2010.

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  1. AD is a posh way of describing a biological way to get rid of S**T.

    Simple as that.
    The Govt has committed to big investment in this, which might see fewer rotten old rubbish incinerators being built, but more combined sewage treatment and power plants.

    Basically, you use bacteria to digest the sewage, and any other organic rubbish, then burn off the methane for heat and power. Some goes to keeping the process going, the rest goes to the National Grid. What's left over should be a sterile but valuable fertiliser.

    It's quite big in Europe, and does have some significant advantages over other power generation, and reduces air and water pollution (No smoke, you see).

    Now, wiser men than me will already be looking to the angles here, but I would see big investment in refitting existing Water treatment works, and I can see that a lot of farmers might do quite well out of this. Cows do produce a LOT of crap. At present its a nuisance. Now it could be an asset.

    for a rough overview.
  2. OldSnowy

    OldSnowy LE Moderator Book Reviewer

    I presume therefore that Westminster and Whitehall will be able to power most of London?
  3. Depends. We run on hot air, but we just chucked a lot of organic debris back to Scotland without stuffing it in the vat.

    Do you want me to summon them back?
  4. "L casei immunitas" or "bifidus digestivum", that is the question.
  5. There are also bio-degradable golf tees made (afaik) wheat starches. Usable for a few tee-offs, and when they break, just leave them there. In a couple of weeks, all gone.
  6. It´s really taking off over here even small farms are getting on to it,instead of spreading the muck over their fields and just mostly over dunging them and poisoning the streams and rivers they´re using the methane to heat their houses etc.Wood pellet burning stoves are on the increase as well as farmers tell the oil and gas companies to shove their price increases.
    About 40 years ago on British telly there was a guy trying to use methane from chicken sh*t to power his car,the reporter just basically took the p*ss out of him,a great shame as this could have been developed and perfected long before now,instead we´ve been lining the pockets of BP etc.I would think there´s more methane in chicken dung than cow´s ?
  7. Whilst the Gov't of the day may be pushing for a greater adoption of AD, commercially the numbers do not yet stack up - it is very difficult to get a timely return on investment. There is a UK based company that has developed a digester that is suitable for individual farms producing both electricity and fertilizer; the initial cost is £70K thus making any ROI difficult in the short term!
  8. Defra has been lurking around this issue for the past few years.

    Renewables Obligation
    39. Our key mechanism for delivering renewable electricity is the Renewables Obligation, which provides financial support to generators of renewable electricity. Electricity from anaerobic digestion is eligible for support under the Renewables Obligation, and on 1 April 2009 we introduced differentiated support levels for different renewables technologies (known as “banding”). Anaerobic digestion is in the top banding at 2 ROCs/MWh (Renewables Obligation Certificates per Megawatt hour).

    40. With most technologies our policy is not, as a rule, to change the level of support once a generating station has been accredited by Ofgem. (This is known as “grandfathering”.)
    We set out our policy on grandfathering in December 2008, in the Government Response to the Statutory Consultation on the Renewables Obligation Order 200914. We decided not to grandfather biomass, including anaerobic digestion, because biomass electricity generation
    faces ongoing fuel costs which are subject to market fluctuation in an immature market. We recognised the need for flexibility to consider the impact on biomass prices when setting banding levels. As a result, we increased support for all biomass generators, not just new entrants, on the introduction of banding.

    41. Industry and investors have recently highlighted that lack of revenue certainty is proving a major constraint on the development of biomass generators, including anaerobic digestion.
    The 2010 Budget announced that we will consult on changes to the Renewables Obligation Order which offer certainty of support, consumer value and adaptability to biomass price fluctuation. This consultation will include a proposal that existing anaerobic digestion plants are grandfathered at 2 ROCs.

    What is interesting here is that the AD incentives are purely on the alternative energy market. The value of the digested material as a means of reducing the huge amounts of livestock slurry (and expensive storage), the resale value of the residue as fertiliser, and so on are not listed.

    I'd guess that Government is looking to incentivise construction (Read-Subsidise) , and so long as the applicant is willing to tick a few 'green' boxes, there might be cash on the table.
  9. I have been doing it for years..its called a Cess Pit/ Tank!!
  10. Very good question!

    This seems to suggest that cattle manure is best for methane, then pigs, then poultry. Less crap per animal, but you can pack a LOT of chickens in the space for one cow...

    Mind you, the chickens do kick out a hell of a lot of ammonia as well, but that's another issue.

    Really, AD is a bit of a red herring in regard of energy generation, but pretty brilliant at waste disposal, greenhouse gas reduction and fertiliser recycling, and given the costs of building the big tanks needed to hold slurry, they can be seen as a long term investment against that.
  11. I am involved with a new firm who are involved in this. Their current view is that these are viable projects for communities and individual farms, but that as yet we cannot sell a very large amount back to the grid. This will probably change as technology improves.

    In rural communities the infrastructure will be the biggest stumbling block, followed by increased traffic bringing organics for the digester. Farming alone does not provide enough waste for it to be viable without top ups of food waste, vegetable waste and possible human sewage. There could also be strong objection to farmers growing crops purely to feed a digester as this would remove food producing land from the cycle.

    Personally I think these will work for large wealthy farms where infrastructure can be provided by the landowner with access to grants etc and private wealth. Power is then sold back to the local community at a reduced rate which provides the incentive not to object on planning grounds and the remainder is sold back to the grid at the going rate.

    Its a long term investment but farmers tend to be more in favour of long term projects over short term ones.

    The other market is solar energy, utilising the long wide rooves of farm buildings for solar panels etc. Again this will probably only power the farm on which it is placed. Chicken farms will love this as they have a lot of roof space, and need a lot of electricity to run a proper battery/broiler system.

    The best source of green energy we have is tidal power, not wave, but tidal - it is a very strong force, it can be guaranteed twice a day for the rest of eternity and the UK is well placed with a very long coastline for a relatively small landmass and also the North Sea is basically a massive tide pool that empties down the east coast and through the Channel with immense force twice daily - if green energy is what you want this is probably the best option long term.

    Wind power is something of a red herring but is used as visible evidence that the government is committed to green energy.

    Although all of that is academic - nuclear power can do all of this and is actually relatively clean if the waste disposal is well managed.
  12. All true. But most people have no idea of the sheer volume of waste produced.
    There is over 200 million tonnes of raw manure produced each year. Most gets chucked back on the land, but you can't just spread it when you like. There are rules as to how much, where and when you can spread.
    So, farmers have to store it. That's either any expensive (And dangerous- usually a farmer or two gets gassed every year cleaning out slurry tanks) tank farm, or vast open air lagoons of raw crap. Not very appealing at all.

    Anything that reduces that lot, and makes the place a bit cleaner is probaly worth investing in.

    Since AD plants can eat most organic matter, they can get rid of a lt of other old junk as well.

  13. That is all correct, however in many cases it is just not economically viable to move the animal waste the distances to a digester - I am prepping a report into it at the moment and my current findings are that several farms can provide into one digester and still have the capacity to take other waste. Obviously depending on the size of the operation. But to get it past T&C planning (my area) and other community objections you will need to have large digesters to provide power locally. Without that many will be blocked. This situation will change as they become more common but at the moment there is a lot of suspicion.

    A big programme of re-educating peoiple that this is not a particularly filthy operation will be needed. The general public tend to recoiul from anything involving sh!t
  14. Again, all true. I think that the ideal solution is a mix of small, subsidised plants each with an AD serving a group of farms, and a few big, industrial ones probably based at existing landfill or Sewage treatment work sites where the feedstock is already brought to it.

    And yes, the public do get upset about it. It never seems to occur to most people that this stuff either goes into the sea or into the land. Most people are too remote from farming these days.