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Most wood energy schemes are a 'disaster' for climate change
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Treacodactyl
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Joined: 28 Oct 2004
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PostPosted: Thu Feb 23, 17 10:20 am    Post subject: Most wood energy schemes are a 'disaster' for climate change  Reply with quote    

http://www.bbc.co.uk/news/science-environment-39053678

Not at all surprising and worth reading if you're in favour of subsidies and regulation.

tahir



Joined: 28 Oct 2004
Posts: 43879
Location: Essex
PostPosted: Thu Feb 23, 17 10:38 am    Post subject: Reply with quote    

I'm in favour of subsidies and regulation, but I've yet to come across any that are well thought out. My nephew is a commercial lawyer who worked on a thankfully failed biogeneration scheme that would have relied on woodchip from Brazil!

Mistress Rose



Joined: 21 Jul 2011
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PostPosted: Fri Feb 24, 17 7:52 am    Post subject: Reply with quote    

The carbon cycle is one that is very difficult to get your head round and the think tank has failed in this too. If you thin a plantation the remaining trees grow faster as they have more room and light, so take in more energy. If you clear fell and replant, then the new trees won't take in as much energy as you burn, but will do over their life time. If you coppice, which is the traditional way of obtaining fuel wood for both charcoal (main fuel for industry) and logs, the new growth from the coppice will take in a lot of carbon quickly and definitely over the lifetime of the coppice.

I agree that shipping from clear cut areas half way around the world is not going to do anything for the carbon sink, nor is the energy needed to chip huge trees. On the other hand, the smaller wood that might be discarded can be used. Another problem with this is the risk of importing pests and diseases, which is something the Forestry Commission are worried about. If you are alternatively bringing coal, oil or gas from a similar distance, there is a marginal increase in energy as the woodchip has slightly less calorific value.

It is a good idea to use waste first rather than woodchip from newly felled trees, but there isn't enough to go round, which is why we import timber/gas/oil into the UK anyway as we can't grow enough for our energy needs. We have a small island and a large population, so we can't be self sufficient in anything including food and energy.

jema
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PostPosted: Fri Feb 24, 17 8:15 am    Post subject: Reply with quote    

The problem is as just about always, is whether subsidies and regulation are there for the environment or for some lobbyists self interest?

Slim



Joined: 05 Mar 2006
Posts: 4486
Location: New England (In the US of A)
PostPosted: Fri Feb 24, 17 11:55 am    Post subject: Reply with quote    

Clearly it's not a great solution for everyone and everywhere, and clearly accounting needs to be done appropriately.

But some of these ideas are being put forward with a disturbing lack of context.

Though I believe that wood can be used sustainably, and in a manner that is actually carbon neutral, minus cutting and transport emissions, let's go with the idea that new growth isn't taking up 100% of the carbon that harvested wood is emitting when burnt.

What are we comparing that with?
Versus solar power, yup, that's a problem, we're emitting atmospheric carbon where we otherwise only need to do enough to make the panels and components.
Versus literally any fossil fuel? Give me the wood biomass please. That's comparing ancient carbon that would otherwise be stuck under the earth with geologically "recent" carbon that would otherwise be cycling in the forest.

Biomass is fiddling with above ground carbon pools, and needs to be done in a way that doesn't start depleting soil carbon stocks, etc, but anything fossil fueled is dumping ancient carbon into the system where it hasn't been for millions of years with no easy way to get it back out again.

Seriously, which would you prefer?

Also, I'm not saying that Europe should be importing wood chips. What the hell is wrong with you? (not *you* you, but *Europe as a whole* you) Can those economics even work?

Slim



Joined: 05 Mar 2006
Posts: 4486
Location: New England (In the US of A)
PostPosted: Fri Feb 24, 17 12:03 pm    Post subject: Reply with quote    

Here's an example of biomass being done well, with a much lower greenhouse gas equivalent than coal or natural gas

https://www.fpl.fs.fed.us/documnts/pdf2015/fpl_2015_gu001.pdf

Some more interesting considerations

http://www.sciencedirect.com/science/article/pii/S0961953415001798


And apologies for what the hell is wrong with you comment previously. Upon further consideration, shipping wood chips around may still be better than shipping coal, oil, etc around!

Seriously, what is the benchmark that is being compared against?

Is this an example of "it's not perfect, so why do it at all" when the alternative is...... what?

Treacodactyl
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PostPosted: Fri Feb 24, 17 12:27 pm    Post subject: Reply with quote    

Mistress Rose wrote:
The carbon cycle is one that is very difficult to get your head round and the think tank has failed in this too.


I don't think they have. They've pointed out the fact that many simply ignore in that it takes many years for the carbon to be reabsorbed and that's assuming replanted trees will be allowed to regrow and ignoring the carbon used to process and ship the stuff.

We do indeed generate woodchip from more sustainable sources in the UK, arb waste, thinnings, brash from clear fell etc but I gather from those that try and sell the stuff the prices have fallen due to the imported chip.

Mistress Rose



Joined: 21 Jul 2011
Posts: 8482

PostPosted: Sat Feb 25, 17 9:04 am    Post subject: Reply with quote    

Interesting articles Slim. I read the abstracts for both, but think I will look at the whole thing later. Some parts of Europe do not have the room to grow the trees they need for biomass; Britain, the Netherlands and Belgium being examples. Others, such as France and Germany might, and have a tradition of log burning that we don't. Britain has plenty of coal, and the only way we can be self sufficient in energy is actually to use that.

Treacodactyl, yes they were right to highlight those points, but if woodland is regrown, either by new planting or coppicing, over time, all or most of the gas emitted will be reused. I don't recall any work being done on the rain of twigs, leaves and other odd stuff that comes off trees all the time to see how much a tree sheds and is converted to humus over a year, but I am sure someone somewhere has done the work.

A lot does come down to economics and security of supply. The only way to achieve security of supply and the amount needed is to import, but of course that does cut out the extra processing and the transport by road, which is more expensive, of locally produced material. I would love to be able to sell the brash for energy production, but the small amount we produce wouldn't even be an hours burning for a power station.

Treacodactyl
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PostPosted: Sat Feb 25, 17 5:55 pm    Post subject: Reply with quote    

Mistress Rose wrote:
but if woodland is regrown, either by new planting or coppicing, over time, all or most of the gas emitted will be reused.


It's a big if, and reading the link I posted it seems unlikely it will all be replanted. But that is still missing a big point and that is we need to reduce carbon emissions now not 50+ years when the trees that may have been replanted are at the age when they're absorbing a decent amount of CO2 that's been pumped out by burning their parents.

Slim



Joined: 05 Mar 2006
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Location: New England (In the US of A)
PostPosted: Sat Feb 25, 17 7:08 pm    Post subject: Reply with quote    

Treacodactyl wrote:
Mistress Rose wrote:
but if woodland is regrown, either by new planting or coppicing, over time, all or most of the gas emitted will be reused.


It's a big if, and reading the link I posted it seems unlikely it will all be replanted. But that is still missing a big point and that is we need to reduce carbon emissions now not 50+ years when the trees that may have been replanted are at the age when they're absorbing a decent amount of CO2 that's been pumped out by burning their parents.


Agreed, however, what is the alternative to burning that recent carbon?

There is the most ideal solution, and the least ideal solution, and reality is probably somewhere in the middle.

What should the next power plant be? Which power plant should be the first to be shuttered?

I say, the next power plants should be solar/wind if possible, clean modern nuclear next priority, and that the first ones to be shuttered next are coal, then oil and gas in that order.

biomass may not be perfect, but again, what is the comparison being drawn against?

Mistress Rose



Joined: 21 Jul 2011
Posts: 8482

PostPosted: Sun Feb 26, 17 9:30 am    Post subject: Reply with quote    

In the past trees were coppiced for fuel in the UK. This can be anything from a 5-7 year cycle for hazel to about 20 year for other trees. This is hardly waiting 50 years for them to regrow. It worked well for centuries and their offspring are still with us, particularly in Dorset, Hampshire, Sussex and Kent. Willow is even shorter cycle, but to keep going indefinitely needs fertiliser, which the others don't.

I realise that not every country has trees that coppice, but certainly in the UK chipping coppice wood is the best option for power. Coppice wood was used to provide charcoal for iron furnaces before the use of coke, was used into my lifetime to power bread ovens local to me (and we are in suburbia) and is making a comeback in that direction.

Treacodactyl
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PostPosted: Sun Feb 26, 17 9:50 am    Post subject: Reply with quote    

We're not talking about what could possibly be done, we're talking about what is actually being done such as the importation of wood biomass from the US and Canada, much is non-coppicable pine and the broadleaves they are felling don't appear to be managed sensibly but are clear felled forest.

Slim



Joined: 05 Mar 2006
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Location: New England (In the US of A)
PostPosted: Sun Feb 26, 17 2:12 pm    Post subject: Reply with quote    

Treacodactyl wrote:
We're not talking about what could possibly be done, we're talking about what is actually being done such as the importation of wood biomass from the US and Canada, much is non-coppicable pine and the broadleaves they are felling don't appear to be managed sensibly but are clear felled forest.


Canadian forestry includes some of the best practices in the world! They have strict rules regarding re-planting.

And yes the discussion of what is being done necessitates discussion of what can possibly be done.

If you stop the current biomass system currently set up, what do you replace it with? If you alter the current system because of these concerns, what do you change?

Right now all that I'm seeing is "I don't like this". Where does that get anybody?

Treacodactyl
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PostPosted: Sun Feb 26, 17 2:42 pm    Post subject: Reply with quote    

Slim wrote:
Right now all that I'm seeing is "I don't like this". Where does that get anybody?


I could say all I see is people trying to deliberately mislead themselves and others.

I understand you can get biomass from short rotation coppice but that doesn't mean most of the biomass we burn in the UK comes from that. I understand some places manage forestry well but that doesn't mean everywhere does, etc.

I've said many times before I would prefer some of the money that's poured into renewables to go into reducing our demand for energy.

Slim



Joined: 05 Mar 2006
Posts: 4486
Location: New England (In the US of A)
PostPosted: Sun Feb 26, 17 2:48 pm    Post subject: Reply with quote    

Quote:
I've said many times before I would prefer some of the money that's poured into renewables to go into reducing our demand for energy.


In this thread?
Regardless, I can get behind that.

Do you agree that the reduced demand would be best used to reduce coal usage?

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