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"Carbon Neutral" - Can it be true?

Discussion in 'The Lounge' started by Malcolm_Stewart, Feb 15, 2012.

  1. Malcolm_Stewart

    Malcolm_Stewart Well-Known Member

    From a steam railway tours brochure :-

    "...All our trips are carbon neutral...".

    And a small %age is added to the price of the tickets.

    I assume that this additional charge covers the planting of sufficient trees to soak up the carbon dioxide emitted by the steam loco when burning several tons of its prime fossil fuel, coal. Somehow I simply don't trust the calculations, and it wouldn't surprise me if the charge gets syphoned off en-route to the nursery forest. Am I being too sceptical? Or are these schemes open to truly independent assessment?

    Anyone else given it a thought?
  2. P_Stoddart

    P_Stoddart Well-Known Member

    Maybe the use the extra charge to buy shares in wind farms. :D
  3. Malcolm_Stewart

    Malcolm_Stewart Well-Known Member

    Don't get me going on about windfarms!

    I fail to see how they can possible pay for the energy used in extracting the minerals used in the construction, the refining, metal-bashing and assembly etc. And then there's the new roads to the site of the farm, the energy used in making the cement for the concrete foundations, the cabling etc. I just don't believe it. And they're switched off much of the time.

    Prof Fells views

    What's wrong with ever present tidal power?
  4. Wheelu

    Wheelu Well-Known Member

    Just stand on a motorway overbridge for a few minutes and watch the traffic zoom past. The emissions from a one off steam special won't even register on the scale in comparison. I wouldn't get upset about it, carbon neutral or otherwise ;)

    Re wind tide and all other renewables, take a look at this book to get the facts.
  5. beejaybee

    beejaybee Marvin

    The calculations are at best crude, the ones I've seen completely fail to take into account that a tree is not really a carbon sink but carbon storage - the CO2 it absorbs whilst it is growing is likely to be released shortly after it is cut down, whether it is turned into paper or furniture or burned directly. Only trees growing in natural forest are likely to sink any appreciable amount of carbon when they die, and even then the conversion rate is very low - typically about 1%.

    It would be better for the steam engine to be fuelled by wood cut from forestry plantations replanted after felling. This actually works pretty well without significant modifications to the locomotive. OTOH if you modified the thing to burn methane harvested from landfill, you could with some justification say that the operation was environmentally beneficial, since methane released to the atmosphere is scores of times worse from the point of view of greenhouse warming than burning it and releasing the resultant CO2 and water.
  6. Wheelu

    Wheelu Well-Known Member

    Ah but the ultimate solution is to use a wind farm to generate electricity which is in turn used in the electrolysis of water to produce hydrogen that is burnt in the steam loco. No carbon involved at all :)
  7. beejaybee

    beejaybee Marvin

    Gonna need a robot driver then. And getting the fireman to shovel H2 into the firebox is a bit tricky.

    Making steel necessarily uses a lot of coal - about 100 tons of coal for every ton of steel produced using the common Bessemer process IIRC. It's not just energy, the iron oxide needs to be reduced to metal, and then steel also contains a small quantity of carbon. So there's a good few thousand tons of CO2 in the atmosphere resulting from the manufacture of the steam engine .... it's not a carbon free operation even if there were zero CO2 emissions from running it.
  8. AGW

    AGW Well-Known Member

    Locking up the carbon (any carbon) in wood aint going to do much good for the atmospheric gas balance. This form of sequestration is temporary. You would need to commit to burrying the wood in a secure airtight hole to ensure that the carbon cant skip back into the air. We need to think on a geological time scale if we are going to make any real dent in the issue.

  9. TimF

    TimF With as stony a stare as ever Lord Reith could hav

    Call me a cynic but it sounds like an excuse to add a surcharge
  10. Wheelu

    Wheelu Well-Known Member


    Nice clean job and it sure doesn't weigh as much as coal.
  11. MickLL

    MickLL In the Stop Bath

    Something for consideration.

    I don't believe that proponents of tidal power are thinking it through properly.

    The example I'll give is, I know, simplistic and in some respects out of date. It makes a valid point though.

    Imagine, as has often been proposed, that a great barrage was built across the Severn Estuary. The tide fills the lagoon and the water is released slowly as power is needed.

    It's self evident that such an arrangement would utterly change the tidal pattern both upstream and downstream of the barrage.

    I have never seen any discussion at all about the impact of the tidal change on the ecology of the area. It's equally self evident that the tide pattern couldn't be so dramatically altered without having some impact.

    End of 'sensible' point.

    Now a completely outrageous one.

    If the rotation of the earth is resisted by a wind turbine or gravity interfered with by tidal power aren't we going to eventually slow the earth down and get us nearer to the sun and therefore make everything worse.

  12. AGW

    AGW Well-Known Member

    No such thing as a free lunch!

  13. RogerMac

    RogerMac Well-Known Member

    1. There are other sources of tidal power apart from barrages. For example an underwater turbine off Portland Bill would tap into a tidal race that carries enormous energy - some of these streams regularily reach 13 knots. In fact the UK is rather well suplied with suitable sites, and the speeds being predictable the turbines do not have to designed to cope with the occassional freak conditions that wind turbines are subject to.

    2. Tapping tidal energy will eventually slow the rotation of the earth and make the day slightly longer but will not affect its orbit.

  14. beejaybee

    beejaybee Marvin


    The experimental installation at Strangford Lough is small scale but indicative of what could be achieved without significant visual intrusion or environmental impact.
  15. Malcolm_Stewart

    Malcolm_Stewart Well-Known Member

    If my memory is correct, the WWT (to whom I pay a subscription) certainly argued very strongly that any disturbance to the water flows along the Severn would adversely affect the bird life around their internationally important reserve at Slimbridge. Similarly the RSPB are very quick to oppose any changes which might affect roosting / breeding sites for the birds they care about.

    In Milton Keynes which wasn't built 60 years ago, there are now several "balancing lakes", both wet and dry, which are essentially short term reservoirs designed to delay and reduce the potential flooding downstream around the route of the River Great Ouse as a result of the quicker* rain-water run-off caused by concreting over what had been farm land. When I first arrived here 30 years ago, my photos show them working well with large quantities of water held back, but that's not so at the moment. Water levels at my local reserve are lower than ever, and as far as I know, the Ouse Washes haven't flooded this winter. Back to my point, these newly built balancing lakes have made Milton Keynes one of the best areas for birdwatching, with several rarities recorded, as well as now hosting a significant breeding area for Little Egrets. (The furthest from the sea, I believe.)

    *I've now seen car-parks being relaid so as to be porous to rainwater, and to thus help delay the rainwater run-off into the rivers.
  16. MickLL

    MickLL In the Stop Bath

    You need to take my point, think about the important bit (interfering with tides has an ecological impact) and apply it to your own example.

    Let me do it for you.

    If there's a 13 knot tide race then it's inevitable that there will be an associated environment that depends on that tide race.

    If you install a turbine that removes energy from the flow then the less energetic output will be slower. In the impossible situation that all the energy is removed then the output flow would be zero.

    My point is that altering natural phenomena that have persisted for millennia must inevitably have some impact on the associated ecology. It doesn't matter whether it's barrages, underwater turbines or wave generators. My point still stands.

    There's never enough hours in the day so maybe slowing the earth down is a good thing - bet the Unions will want a pay increase. :D

  17. beejaybee

    beejaybee Marvin

    Indeed but there is scope for extracting some of the energy without having a significant effect on the associated ecology - yet still extract enough energy to meet at the very least a major part of the energy we require. Tides are predictable and, with a decent geographical spread, can be relied on to provide energy 24/7 - unlike wind. An issue arises when you get greedy and try to extract the energy too efficiently.

    The Severn Barrage is a care in point here. If you used underwater turbines and extracted 1 or 2 % of the energy, there would be almost no effect on tidal range & the unique ecology would be almost completely unaffected. Stuff a barrier across the estuary, your energy extraction may well be 40 - 50 % but everything upstream is definitely screwed.
  18. LargeFormat

    LargeFormat Well-Known Member

    Good article in New Scientist a couple of weeks ago on "green" energy. It supports Malcolm's views on wind farms. The other problem is that the churning effect of wind mills actually causes warming over enormous areas. Wind mills seem just another of these money making weezes everyone latches on to.
  19. MickLL

    MickLL In the Stop Bath

    Settle down now I wanna tell you a story. Apologies in advance for historical licence.

    Once upon a time Stone Age Sam was chewing on his raw Pterodactyl when SWMBO said, "Sam I'm a bit fed up with raw food. Why don't we burn some of that wood over there and cook our food." Sam didn't know of course that the wood was home to a whole ecosystem and that, eventually, when McTrceratops became a global brand and was spreading obesity over the world then all the wood would get burned down to the last twig.

    Then a while later Iron Age Ian was sitting by his wood fire when SWMBO said, "Ian I'm fed up with all this wood gathering. If we use some of that coal over there the fire would be much hotter and last longer". Bert didn't know of course that when everyone played the same game all the coal would be used up, the earth would warm up and we would all drown in our own sweat.

    Later still Green George comes along and says, "Well we've used all the coal and other hydrocarbons so we will need to do something different. I know. We will dam all the estuaries, build windmills all over the place dig great holes in the ground to cool the earth's core and all of our energy will be free, inexhaustible and very, very green. All we have to do is make lots of steel and concrete to make the dams and windmills and find loads and loads of money to persuade people to so our bidding.

    What George didn't know of course was ...........................

    Well you finish it.


    PS Lest anyone think otherwise I am NOT arguing against renewables - just for some honesty and balance in the discussion.
    Last edited: Feb 16, 2012
  20. RogerMac

    RogerMac Well-Known Member

    I think that BeeJayBee has done it for me rather well

    Incidentely there is another type of barrage - the pumped barrage - that has the potential to achieve effeciences over 100% but I did not mention it as it would have environmental impact. In this type of barrage additional water is pumped in at high tide, at say 2metres head. The same water is let out through a turbine at low tide at about 10metres head, generating 5 times the electricity that was used to punp it in.


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