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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorTimSmall
    • CommentTimeAug 4th 2012
     
    Today's episode of "Farming Today" was on Biomass crops - interesting I thought:

    http://downloads.bbc.co.uk/podcasts/radio4/farming/farming_20120804-0700a.mp3

    http://www.bbc.co.uk/podcasts/series/farming

    Tim.
  1.  
    Tim- Thanks for the posting, it is very interesting when you compare it with the previous reasons given for subsidising the production of dedicated biomass in the UK.
    Previous statements claimed that this biomass production would stabilise UK energy costs but the BBC programme detailed a doubling of miscanthus price plus it confirmed the intention to import 79 million tonnes of biomass/yr thousands of miles. This ignores GHG impact, energy required to dry and pelletise timber plus health and environmental costs resulting from degradation of air quality caused by biomass combustion.
    I note UK miscanthus/ straw burning plant operators claim fuel will be sourced within 50 km radius of the plant but the programme reported from a Shropshire farm supplying Ely power station, the Ely power plant representative confirmed they source from Staffordshire. Miscanthus is low energy density which creates substantial transport impact.
    The farmer claimed use of marginal land for miscanthus production but confirmed using all the farm. Farmers are being heavily subsidised to transfer from food crops including wheat to dedicated biomass production but this ignores the increasing need for food and other demands such as the new ethanol plant at Hull requiring 1,100,000 tonnes of wheat each year.
    Where is the due diligence in UK combustion energy policy ?
    • CommentAuthortony
    • CommentTimeAug 6th 2012
     
    Is this stuff dreamed up by politicians.......
  2.  
    Posted By: BrianwilsonThe farmer claimed use of marginal land for miscanthus production but confirmed using all the farm.

    I think I recall a phrase something like "good deep loam" being mentioned for for the initial seed plantings at least.
  3.  
    The farmer also claimed no input after the initial planting, just harvest the crop for years ahead. However you can not take tonnes of biomass/ha out of land without depleting the soil especially with monoculture - so how will the soil nutrition on this 1000ha be maintained or replenished? - Enter high energy demand artificial fertilizer?
    • CommentAuthorJoiner
    • CommentTimeAug 7th 2012
     
    It was more or less tacitly accepted in another (think it was the 'fuel for the 21st century') thread that the definition of "marginal" would gradually be expanded to mean "more or less marginally profitable" as biomass feedstocks assumed a greater importance as an alternative to FF, the truly marginal (in terms of productivity for food) acreages having proved inadequate to feed a growing market. And as fuel has always attracted a premium, the scarcer the product the better price it attracts and the more attractive it becomes. For a business in the business to make profit and faced with the choice: Food or fuel? It's a no-brainer.
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 7th 2012 edited
     
    Posted By: Peter_in_Hungaryso how will the soil nutrition on this 1000ha be maintained or replenished?

    Could be brought in by a stream/river. Though that is, in effect, only increasing the land area needed to grow a crop.
    Does baffle me about biomass as a source of energy. We know that PV can do a better job, so why are we bothering to go down this route. True it can be stored, but so can electricity, would we not be better working on storage systems, they don't have to be complicated, chemical or high tech, just lift a weight up high and then let it fall when needed. As long as the overall efficiency stays higher than the best biomass crop we are winning.
    • CommentAuthortony
    • CommentTimeAug 7th 2012
     
    Here here
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 7th 2012
     
    One of the best current-technology solar energy systems we have on the scale required *is* biomass, for the UK.

    Rgds

    Damon
    •  
      CommentAuthorJSHarris
    • CommentTimeAug 7th 2012 edited
     
    <blockquote><cite>Posted By: DamonHD</cite>One of the best current-technology solar energy systems we have on the scale required *is* biomass, for the UK.

    Rgds

    Damon</blockquote>

    How do you reach that conclusion?

    The very best, most efficient biomass crops struggle to get better than around 6 to 8 % energy conversion ratio, yet existing PV manages double that with ease. This means that biomass crops require more than double the land area for a given energy output than PV would require, a point already made somewhere in the depth of the bimass thread.

    The only advantage that biomass has is easy storage, but that's offset to some degree by the energy that needs to be expended in preparing the stuff for use as fuel, that used in transporting it to where it's needed and in the treatment and removal of the waste products once energy has been extracted from it.
  4.  
    Peter- The BBC programme detailed miscanthus is a 20-30 yr 12ft high monoculture and as you confirm requires minimum input. This causes concern at various levels, replacing food production, changing the face of the countryside with impact on biodiversity and the transfer will seriously reduce agricultural employment.
    I thought the justification for transferring land out of food production was interesting, making the excuse that years ago we had to devote a third of our land to providing feed for horses, we also had far less people to feed.
    The claim that burning biomass reduces reliance on fuel imports falls down when the reality is the massive subsidies are encouraging the large users to import millions of tonnes. 90% import far higher than gas and most important we know the combustion of biomass degrades air quality adding £billions to health and environmental costs plus it is generally used in low efficiency power plants adding to waste of energy.
    It appears Tony is right, it is politics but to what end and at what cost to the public?
    p.s. You are right Steamy ,storage does appear to be the answer but our money is being diverted elsewhere.
  5.  
    Reference storage of biomass, with regard to straw we know 25% can be rendered unsuitable for purpose during storage and 12% lost due to arson. Woodchip comes with storage problems, spores ,self ignition etc. Pellets , ingress of moisture?
    I note a small biomass power proposal on a Scottish Island will burn green timber straight from a good store, the forest , water content estimate over 50% , sadly PM creation will be 200g plus per Gj of energy in equating to exhaust emissions from 39 million diesel vehicle km /day, process efficiency obviously poor but fuel is cheap. Where is the due diligence and duty of care when aware of clean alternatives?
    Dave is correct money appears to motivate actions in all aspects of energy provision but who pays the price, people like Mikee sadly
    • CommentAuthorEd Davies
    • CommentTimeAug 7th 2012
     
    Posted By: SteamyTeaTrue it can be stored, but so can electricity, ..., just lift a weight up high and then let it fall when needed.

    Really? In a gravitational field of 10 N/kg (i.e., a field causing an acceleration of 10 m/s², slightly more than Earth's) lifting a mass of 1 kg through 1 metre stores 10 J. 1 kWh is 3600 kJ so to store 1 kWh you'd need to lift 1 kg though 360 km or 1 tonne through 360 metres. I applaud your imaginative use of the word 'just'.
    •  
      CommentAuthorJSHarris
    • CommentTimeAug 7th 2012 edited
     
    <blockquote><cite>Posted By: Ed Davies</cite><blockquote><cite>Posted By: SteamyTea</cite>True it can be stored, but so can electricity, ..., just lift a weight up high and then let it fall when needed.</blockquote>
    Really? In a gravitational field of 10 N/kg (i.e., a field causing an acceleration of 10 m/s², slightly more than Earth's) lifting a mass of 1 kg through 1 metre stores 10 J. 1 kWh is 3600 kJ so to store 1 kWh you'd need to lift 1 kg though 360 km or 1 tonne through 360 metres. I applaud your imaginative use of the word 'just'.</blockquote>

    Works OK for pumped storage stations, like Dinorwig. Not high efficiency, but certainly workable and a way of making use of periods when generation exceeds demand.

    Just checked the figures, it's actually not as bad as I thought. Input power is 275 MW for 7 hours (so 1925 MWh), output power is 288 MW for 5 hours (so 1440 MWh). Looks like it runs at just under 75% efficiency as an electrical energy store, which isn't bad at all when compared with other technologies around.
    • CommentAuthorEd Davies
    • CommentTimeAug 7th 2012 edited
     
    Those numbers look about right for each of Dinorwig's 6 turbines.

    Still: http://en.wikipedia.org/wiki/Dinorwig_Power_Station

    1650 MW for JSH's quoted 5 hours is 8250 MWh. Construction cost was £425 million so that's 5.15 p/Wh - about the same order of magnitude cost as forklift batteries.

    Also, construction started in 1974 so that cost needs to be inflated by some amount. The cost of Dinorwig was probably higher than it might be in other locations if there isn't the requirement to bury stuff for aesthetic reasons - but presumably they took on that cost because there aren't a lot of places in the UK where such schemes make sense.

    Dinorwig plays a valuable role in managing the rapid changes in demand on the grid but it ain't a sensible way to store energy in general.
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 7th 2012 edited
     
    JSH: "The only advantage that biomass has is easy storage" is *the* prime advantage to store the scale of energy required for GB to ride out one of DECC's 5-cold-windless-days scenarios. I know that the conversion ratio of biomass cf PV is horrible (which is why I am a fan of PV), but there is simply no electricity storage on a similar scale available to us yet, other than flooding much of Scotland and Wales and the Lake District, which I think would be even more unpopular than (properly) burnt biomass.

    rgds

    Damon
    •  
      CommentAuthorfostertom
    • CommentTimeAug 7th 2012
     
    Posted By: Ed Daviesto store 1 kWh you'd need to lift 1 kg though 360 km or 1 tonne through 360 metres
    Thanks for that - puts a scale on things, which I will now stop touting.
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 7th 2012 edited
     
    Posted By: DamonHDflooding much of Scotland and Wales and the Lake District, which I think would be even more unpopular than (properly) burnt biomass.

    How about France :wink:

    Using that 75% efficiency figure for pumped storage and my daily winter usage of up to 30 kWh and Eds figures of 1 tonnes lifted 360 m per kWh and if I swapped the water for iron at about 7 tonnes/m^3 and limited the lift to 6 m, then:

    Mass would be 5250 tonne, which would be 750 cubic meters lifted 6 m. Could 'just' about fit that in my back garden.
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 7th 2012 edited
     
    Are you asking me if I have any objection to flooding France for our convenience, or burning it in lieu of storage? %-P

    Rgds

    Damon

    PS. Ignoring the veracity of the numbers for now, you really want a 5kt mass in your back garden? I'd like to see you get that through planning. And we won't talk about dense urban areas! B^>
    • CommentAuthorJoiner
    • CommentTimeAug 7th 2012
     
    You wouldn't see it for all the other stuff he's got piled there. :wink:
    • CommentAuthorEd Davies
    • CommentTimeAug 7th 2012
     
    If you used a (small) black hole you could keep it within 200 mm of the wall in England and Wales and within 1 metre in Scotland so it would be permitted development.
    •  
      CommentAuthorJSHarris
    • CommentTimeAug 7th 2012
     
    Rather than steel, maybe the answer is to use some of that waste depleted uranium we have stockpiled. It'd only take up about 40% of the volume of steel for the same stored energy..................
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 7th 2012
     
    But given a typical modern UK house is ~50t incl foundations at a guess then black hole or not would there be a significant risk of your now 100x heavier beast digging itself a hole and vanishing?

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 7th 2012
     
    Posted By: DamonHDdigging itself a hole and vanishing?

    Where I thought of putting it, then covering it over with the earth :wink:

    Can't really be 5 kt can it to store 30 kWh
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 7th 2012
     
    Could be, I haven't checked the numbers, but it takes a lot of water lifting to store a small amount of energy, thus the difficulty with doing enough unless you have LOTS of big lakes with drops and FEW people, like, say, Norway...

    It's no wonder that fossil fuels are so attractive.

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 7th 2012
     
    Posted By: DamonHDIt's no wonder that fossil fuels are so attractive.


    Petroleum is just a fantastic product, and you can get if from drilling a small hole in the ground as well.
    •  
      CommentAuthorfostertom
    • CommentTimeAug 7th 2012
     
    Posted By: Ed Davies5.15 p/Wh - about the same order of magnitude cost as forklift batteries
    How's it compare with expected cost of a huge battery bank aka the future national fleet of electric vehicles as currently plugged-in on a smart (discharge as well as charge) tariff?

    Won't that transform the prospects of notoriously interruptible wind/solar/wave generation, which (for want of such storage) are presently lumbered with the need for gas turbine generators on standby? Won't that trump the 'storable energy' benefit of biomass as fuel?
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 7th 2012 edited
     
    I suspect that storage will be a mix of technologies, just like generation, so no one technology will be a 'one size fits all'.
    Will come down to:

    Pumped Storage (other gravity methods)
    Flywheel
    Battery
    Hydrogen
    Compressed Air/gas
    Temperature (hot and cold)
    Super Capacitors
    •  
      CommentAuthorfostertom
    • CommentTimeAug 7th 2012
     
    What is the prognosis for breakthro (to large scale) on these various storages? Do policymakers acknowledge that this will bring interruptible ('renewable') generation in from the cold, against miserable interventions like http://repealtheact.org.uk/blog/4304 (article I saw in today's Mail)
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