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Source: (consider it)
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Thread: Ethics of heating fuel choices
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mr cheesy
Shipmate
# 3330
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Posted
I was reading this interesting comment from the British Medical Journal, which suggests that wood-burning stoves - by some measures of air pollution - are worse than road transport.
In the UK it is fairly common for middle-class people to want to have all or part of their heating from burning wood, and there have been suggestions that smog in some Scandinavian cities is being caused by the number of wood-burning stoves.
The problem is that there are many competing ethical issues with regard to heating fuel choices. On the one hand, wood may look better in terms of local fuel security, sustainability and CO2 emissions (depending exactly on what you're considering). And is it a good idea to have the populations of so many European countries so dependent on a single source of natural gas?
But then on the other hand, obviously having many small, inefficient burners in homes is going to increase smoke and increase emissions. Burning anything in a power station is bad, but clearly it must be better than everyone burning their own stuff.
Anyone see a way through these dilemmas? Are there not ethical problems with whichever fuels are chosen?
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arse
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Honest Ron Bacardi
Shipmate
# 38
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Posted
An interesting question Mr. Cheesy.
I suspect part of the answer is that wood-burning stoves are easy to make, have been around since the dawn of time, and were never made with efficiency in mind. The comments on air quality - especially in Scandinavia where these things are probably the most used - are probably skewed by that fact.
I'm pretty sure that if you set a physicist and an engineer loose on the design, you'll get something that is quite different. This sort of thing, for example. I've no idea what that does in terms of reducing microparticulates, but they must surely be lower, maybe a lot lower. Another technique which I've seen used on American designs is to use a catalytic after-burner.
There are also a whole lot of other interlocking issues concerning urban air quality, NOx, fuel eficiencies and sustainability, etc. etc.
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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mr cheesy
Shipmate
# 3330
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Posted
quote:
Originally posted by Honest Ron Bacardi:
I suspect part of the answer is that wood-burning stoves are easy to make, have been around since the dawn of time, and were never made with efficiency in mind. The comments on air quality - especially in Scandinavia where these things are probably the most used - are probably skewed by that fact.
That's an interesting point, but I'm not very convinced by manufacturer's glossy brochures: a wood burner can both be the most efficient of its type whilst still being far less efficient and far more emitting than standard gas convection boilers.
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arse
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betjemaniac
Shipmate
# 17618
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Posted
quote:
Originally posted by mr cheesy:
I was reading this interesting comment from the British Medical Journal, which suggests that wood-burning stoves - by some measures of air pollution - are worse than road transport.
In the UK it is fairly common for middle-class people to want to have all or part of their heating from burning wood, and there have been suggestions that smog in some Scandinavian cities is being caused by the number of wood-burning stoves.
The problem is that there are many competing ethical issues with regard to heating fuel choices. On the one hand, wood may look better in terms of local fuel security, sustainability and CO2 emissions (depending exactly on what you're considering). And is it a good idea to have the populations of so many European countries so dependent on a single source of natural gas?
But then on the other hand, obviously having many small, inefficient burners in homes is going to increase smoke and increase emissions. Burning anything in a power station is bad, but clearly it must be better than everyone burning their own stuff.
Anyone see a way through these dilemmas? Are there not ethical problems with whichever fuels are chosen?
Swings and roundabouts really - I live in a tiny cottage in the sticks. I've got a wood burner in the sitting room and it heats the whole house effectively (because the building's so small). I actually had the gas board query my meter reading the other day because all I've used gas for really over the winter has been the shower in the mornings.
Wood is either bought in or just gathered from windfall in the local woods/fields. So far it has cost me about £30 for 5 months' heating.
I think possibly the answer is going to be different depending on where you live - lots of people living on top of each other in a city, and buying in their wood (which has had to be brought into the city in the first place) is probably worse than isolated villages with an abundance all around them and a population of a couple of hundred.
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And is it true? For if it is....
Posts: 1481 | From: behind the dreaming spires | Registered: Mar 2013
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mr cheesy
Shipmate
# 3330
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Posted
quote:
Originally posted by betjemaniac:
Swings and roundabouts really - I live in a tiny cottage in the sticks. I've got a wood burner in the sitting room and it heats the whole house effectively (because the building's so small). I actually had the gas board query my meter reading the other day because all I've used gas for really over the winter has been the shower in the mornings.
Wood is either bought in or just gathered from windfall in the local woods/fields. So far it has cost me about £30 for 5 months' heating.
I think possibly the answer is going to be different depending on where you live - lots of people living on top of each other in a city, and buying in their wood (which has had to be brought into the city in the first place) is probably worse than isolated villages with an abundance all around them and a population of a couple of hundred.
OK, that's fair: I don't think anyone is arguing that wood fuel is not the best solution for isolated rural households. But clearly the demand for wood burning stoves and boilers is not just for people in rural areas - and by some measures the emissions from a wood burner are 1000 times worse than from a gas boiler.
So in an isolated rural area where the emissions are quickly dissipated, this isn't an issue. In a slightly more built-up, or even in a urban area, this can be a major problem.
It would be interesting to see what the air quality is like in a village where people are burning wood fuel.
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arse
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betjemaniac
Shipmate
# 17618
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Posted
quote:
Originally posted by mr cheesy:
quote:
Originally posted by betjemaniac:
Swings and roundabouts really - I live in a tiny cottage in the sticks. I've got a wood burner in the sitting room and it heats the whole house effectively (because the building's so small). I actually had the gas board query my meter reading the other day because all I've used gas for really over the winter has been the shower in the mornings.
Wood is either bought in or just gathered from windfall in the local woods/fields. So far it has cost me about £30 for 5 months' heating.
I think possibly the answer is going to be different depending on where you live - lots of people living on top of each other in a city, and buying in their wood (which has had to be brought into the city in the first place) is probably worse than isolated villages with an abundance all around them and a population of a couple of hundred.
OK, that's fair: I don't think anyone is arguing that wood fuel is not the best solution for isolated rural households. But clearly the demand for wood burning stoves and boilers is not just for people in rural areas - and by some measures the emissions from a wood burner are 1000 times worse than from a gas boiler.
So in an isolated rural area where the emissions are quickly dissipated, this isn't an issue. In a slightly more built-up, or even in a urban area, this can be a major problem.
It would be interesting to see what the air quality is like in a village where people are burning wood fuel.
My village has a population of 290 who live in two roads running east-west parallel to each other. The roads are separated not by houses, but by 100 yards of field. The southerly road is about 90 feet higher than the northerly one; the prevailing winds are southerlies. I think we're (probably rightly) more concerned about emissions from passing traffic. I think you covered it well with "quickly dissipated."
Other locations may of course vary.
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And is it true? For if it is....
Posts: 1481 | From: behind the dreaming spires | Registered: Mar 2013
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Honest Ron Bacardi
Shipmate
# 38
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Posted
quote:
Originally posted by mr cheesy:
quote:
Originally posted by Honest Ron Bacardi:
I suspect part of the answer is that wood-burning stoves are easy to make, have been around since the dawn of time, and were never made with efficiency in mind. The comments on air quality - especially in Scandinavia where these things are probably the most used - are probably skewed by that fact.
That's an interesting point, but I'm not very convinced by manufacturer's glossy brochures: a wood burner can both be the most efficient of its type whilst still being far less efficient and far more emitting than standard gas convection boilers.
You mean a condensing boiler? There's very little in it. Gas condensing boilers usually claim "over 90% thermal efficiency". I get mine checked every year and it typically turns in a figure of 92%. But it has a fearsome array of electronic controls to achieve that.
The log stove I illustrated (no experience or interest in it BTW) claims 89% thermal efficiency as measured by independent labs. I'm pretty sure if you added the level of controls my gas boiler has, you could probably shave another couple of percentage points off it. But they are already very close in efficiency.
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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mr cheesy
Shipmate
# 3330
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Posted
quote:
Originally posted by Honest Ron Bacardi:
The log stove I illustrated (no experience or interest in it BTW) claims 89% thermal efficiency as measured by independent labs. I'm pretty sure if you added the level of controls my gas boiler has, you could probably shave another couple of percentage points off it. But they are already very close in efficiency.
Ah now there is something odd about efficiency ratings for boilers which I can't quite recall - which I think means it is possible to have >100% efficiency and that apparently small differences are actually quite large.
I'll have to look it up, I can't remember where I read about it.
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arse
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Honest Ron Bacardi
Shipmate
# 38
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Posted
Forgot to add - though it should be obvious - that if you are to compare relative capabilities of the two fuels, you need to compare like with like. Gas boilers have been regulated for years in terms of minimum allowable efficiencies, emissions etc. Log stoves haven't. If we are talking about new stoves, then if the particulate emissions can be regulated, regulations on not selling and using the crap older models seem like the more obvious choice.
But there a number of ifs and buts in there still I agree. I doubt if log burners are the way to go for city houses. But unnecessarily stringent regulation that affects country dwellers who have ready access to timber would be perverse.
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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Honest Ron Bacardi
Shipmate
# 38
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Posted
quote:
Originally posted by mr cheesy:
quote:
Originally posted by Honest Ron Bacardi:
The log stove I illustrated (no experience or interest in it BTW) claims 89% thermal efficiency as measured by independent labs. I'm pretty sure if you added the level of controls my gas boiler has, you could probably shave another couple of percentage points off it. But they are already very close in efficiency.
Ah now there is something odd about efficiency ratings for boilers which I can't quite recall - which I think means it is possible to have >100% efficiency and that apparently small differences are actually quite large.
I'll have to look it up, I can't remember where I read about it.
That must refer to something else. A thermal efficiency of greater than 100% would represent a violation of the laws of thermodynamics, and you may well have invented the world's first perpetual motion machine!
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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betjemaniac
Shipmate
# 17618
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Posted
forgot to say - at least I've got gas as an option - over half the village is on fuel oil...
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And is it true? For if it is....
Posts: 1481 | From: behind the dreaming spires | Registered: Mar 2013
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Honest Ron Bacardi
Shipmate
# 38
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Posted
quote:
Originally posted by mr cheesy:
This document explains why some condensing boilers report efficiencies of over 100%.
Ah, right. It relates to condensing boilers being able to capture extra energy from the latent heat of condensation which a non-condensing boiler clearly cannot.
But I don't think it affects the main line of the argument. Any boiler can theoretically be run in condensing mode (our church has a condensing oil-fired boiler) but it needs to be designed for it ab initio.
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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mr cheesy
Shipmate
# 3330
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Posted
quote:
Originally posted by Honest Ron Bacardi:
But I don't think it affects the main line of the argument. Any boiler can theoretically be run in condensing mode (our church has a condensing oil-fired boiler) but it needs to be designed for it ab initio.
I'm sure that's true, but then it must also be true that the standard wood burner is not doing this.
I'm not being difficult: it seems to me that there is a very clear difference here between common (maybe all?) household wood burners and common household condensing gas boilers.
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arse
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Honest Ron Bacardi
Shipmate
# 38
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Posted
I'd guess that it's a qualified "yes" to that. 89% (87% for larger models) sounds close to the quoted 87% efficiency cited for the Baxi gas boiler running in non-condensing mode.
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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orfeo
Ship's Musical Counterpoint
# 13878
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Posted
Local environment definitely makes a significant difference to the air pollution issue. The valley I live in is the part of the city with a notable history of pollution from wood burning, because of the depth of the valley and the overnight temperatures in winter. An inversion layer traps the smoke.
There's been a rebate program to encourage people to switch to other forms of heating, and somewhat controversially there's been a ban in some new suburbs. But it's also an issue about incorrect use of the heater/poor choice of wood, greatly increasing the amount of smoke created.
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Technology has brought us all closer together. Turns out a lot of the people you meet as a result are complete idiots.
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lilBuddha
Shipmate
# 14333
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Posted
Wood is not a viable heating source for populations of any significant size.
Even if the stove linked is as efficient as claimed,* most people burning wood are not using effecient units.
*independant labs do not rate products on a whim. Typically, a manufacturer brings in a product with specific parameters to use. I could design a procedure with the outcome being that I am the tallest person in the world.
hint: the lil in my board name ain't for nothing.
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I put on my rockin' shoes in the morning
Hallellou, hallellou
Posts: 17627 | From: the round earth's imagined corners | Registered: Dec 2008
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Honest Ron Bacardi
Shipmate
# 38
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Posted
I'm pretty sure that in the EU, any producer will need to specify that the appliance needs to be tested to the appropriate EN standard, without which it won't receive its CE certification. But I'm not 100% on that. Maybe if I get a moment tomorrow I'll phone and ask.
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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Carex
Shipmate
# 9643
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Posted
In this part of Oregon wood stoves are tightly regulated: older existing ones are permitted, but if you sell a house with such a stove it must be destroyed and a new heat source installed. Most modern "wood burning" stoves burn wood pellets and are optimized for maximum efficiency / reduced particulate emission.
And when the smog levels get high, stove use may be prohibited.
This affects a lot of rural parts of the Willamette valley as well, where natural gas service is not available, so fuel oil, bottled propane, or electric heat are common.
I think conditions are less strict in some parts of the State that have fewer problems with trapped smog.
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quetzalcoatl
Shipmate
# 16740
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Posted
My neighbour's chimney fell down, and the insurers blamed wood burning, because of excess moisture. Don't know if that's true.
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I can't talk to you today; I talked to two people yesterday.
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Gramps49
Shipmate
# 16378
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Posted
I remember when my neighbor behind me had a chimney fire.
Posts: 2193 | From: Pullman WA | Registered: Apr 2011
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Ricardus
Shipmate
# 8757
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Posted
Am I right in thinking that wood gives off emissions as it decomposes? If so, this presumably ought to be offset against the emissions caused by burning.
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Then the dog ran before, and coming as if he had brought the news, shewed his joy by his fawning and wagging his tail. -- Tobit 11:9 (Douai-Rheims)
Posts: 7247 | From: Liverpool, UK | Registered: Nov 2004
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lilBuddha
Shipmate
# 14333
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Posted
Decaying wood emits mostly methane whilst burning emits CO2. Both are greenhouse gasses, but decay releases at a much slower rate.
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I put on my rockin' shoes in the morning
Hallellou, hallellou
Posts: 17627 | From: the round earth's imagined corners | Registered: Dec 2008
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Baptist Trainfan
Shipmate
# 15128
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Posted
quote:
Originally posted by quetzalcoatl:
My neighbour's chimney fell down, and the insurers blamed wood burning, because of excess moisture. Don't know if that's true.
I believe I'm right in saying that woodburners have caused a number fires in thatched cottages in our part of the world. It's not to do with sparks, but with incorrect installation which means that the flue temperature has got higher than it would have done with simple open fires.
Posts: 9750 | From: The other side of the Severn | Registered: Sep 2009
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mark_in_manchester
not waving, but...
# 15978
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Posted
quote:
quote:
Any boiler can theoretically be run in condensing mode (our church has a condensing oil-fired boiler)
quote:
I'm sure that's true, but then it must also be true that the standard wood burner is not doing this.
As I understand it, if you condense combustion gasses (containing a lot of water in a gas situation) then you can recover the latent heat of vaporisation, which goes towards heating your water in the heat exchanger. There is water vapour in wood smoke too, but things are a little different when you burn with a restricted air supply (as in a wood stove) which is efficient, the fuel is long-lasting, and nothing like as much heat goes up the chimney as with an open fire. Here, you're effectively running a kind of self-fuelling charcoal burning situation, a bit like a coal-gas / coal tar / coke conversion, but without a retort. As well as producing charcoal which is then consumed you make wood-gas (which burns straight away) and wood-tar, some of which burns and some of which goes up the chimney. If the exit temp is too low then it condenses at the top of your flue and clags things up rightly.
I burn skip-wood in a city, so the fuel is free and going to waste anyway. The main thing is that in a big leaky old house I only heat one room where I go to sit to warm up, read or relax, whereas the gas central heating which the rest of the family lob on as they come in heats the whole place, regardless of where anyone actually is. I've made a lot more secondary glazing this year but still, heating one room and keeping the door closed is always going to consume less Joules than heating the whole place. My family can't always be persuaded to turn lights off, let alone get pro-active with radiator valves...
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"We are punished by our sins, not for them" - Elbert Hubbard
(so good, I wanted to see it after my posts and not only after those of shipmate JBohn from whom I stole it)
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mark_in_manchester
not waving, but...
# 15978
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Posted
...actually, looking at the thermometer, I do the family an injustice. Kids tolerate dressing in the morning in an unheated house (a balmy +11 deg C this morning - spring must be coming) and they put jumpers and dressing gowns on before venturing that maybe it's time to burn some of Vladimir's finest. And the missus works long hours, so that's for someone else's gas bill / conscience!
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"We are punished by our sins, not for them" - Elbert Hubbard
(so good, I wanted to see it after my posts and not only after those of shipmate JBohn from whom I stole it)
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Pulsator Organorum Ineptus
Shipmate
# 2515
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Posted
quote:
Originally posted by Honest Ron Bacardi:
quote:
Originally posted by mr cheesy:
This document explains why some condensing boilers report efficiencies of over 100%.
Ah, right. It relates to condensing boilers being able to capture extra energy from the latent heat of condensation which a non-condensing boiler clearly cannot.
But I don't think it affects the main line of the argument. Any boiler can theoretically be run in condensing mode (our church has a condensing oil-fired boiler) but it needs to be designed for it ab initio.
Erm ... surely the latent heat that is recovered from condensing steam originated in the fuel that was put into the system in the first place?
Posts: 695 | From: Bronteland | Registered: Mar 2002
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Arethosemyfeet
Shipmate
# 17047
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Posted
quote:
Originally posted by lilBuddha:
Decaying wood emits mostly methane whilst burning emits CO2. Both are greenhouse gasses, but decay releases at a much slower rate.
On the flip side CH4 is a much more potent greenhouse gas than CO2.
Posts: 2933 | From: Hebrides | Registered: Apr 2012
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Honest Ron Bacardi
Shipmate
# 38
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Posted
quote:
Originally posted by Pulsator Organorum Ineptus:
quote:
Originally posted by Honest Ron Bacardi:
quote:
Originally posted by mr cheesy:
This document explains why some condensing boilers report efficiencies of over 100%.
Ah, right. It relates to condensing boilers being able to capture extra energy from the latent heat of condensation which a non-condensing boiler clearly cannot.
But I don't think it affects the main line of the argument. Any boiler can theoretically be run in condensing mode (our church has a condensing oil-fired boiler) but it needs to be designed for it ab initio.
Erm ... surely the latent heat that is recovered from condensing steam originated in the fuel that was put into the system in the first place?
It's more question of accounting for where the heat energy comes from and goes to. The chemical equations relate to the gaseous state. That's fine for a non-condensing boiler where the water vapour disappears up the flue. But if the water vapour is then condensed, you get a small extra input of heat. Latent heat is only available to you if you change state.
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Anglo-Cthulhic
Posts: 4857 | From: the corridors of Pah! | Registered: May 2001
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Soror Magna
Shipmate
# 9881
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Posted
quote:
Originally posted by mr cheesy:
... In the UK it is fairly common for middle-class people to want to have all or part of their heating from burning wood, and there have been suggestions that smog in some Scandinavian cities is being caused by the number of wood-burning stoves. ...
I found this quite surprising. Practically all older homes in Caprica City have fireplaces, but they were never intended to heat the entire house; that's what the hot water boiler and radiators were for. The fireplaces were decorative; in newer homes they're gas. Around here, wood stoves are, AFAIK, mostly used in rural areas.
quote:
Originally posted by Carex:
... Most modern "wood burning" stoves burn wood pellets and are optimized for maximum efficiency / reduced particulate emission. ...
This affects a lot of rural parts of the Willamette valley as well, where natural gas service is not available, so fuel oil, bottled propane, or electric heat are common. ....
All of which cost waaaaay more than a delivery of firewood. (OMG, don't get me started on the cost of electric heat.) And people who can't afford to buy a full tank of heating oil or propane all at once won't be running out to buy a high-efficiency pellet stove either. Plus a pellet stove won't work during a power outage. I think in most parts of the world, people burn wood because they can't afford or obtain anything else. Ditto for dung. So if we want to reduce the amount of wood being burned, we have to create an affordable and convenient alternative for the poorest people in the world. Let's see ... what's a source of energy that is available practically everywhere on the planet? Look up, look waaaaay up ...
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"You come with me to room 1013 over at the hospital, I'll show you America. Terminal, crazy and mean." -- Tony Kushner, "Angels in America"
Posts: 5430 | From: Caprica City | Registered: Jul 2005
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Alan Cresswell
Mad Scientist 先生
# 31
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Posted
quote:
Originally posted by Arethosemyfeet:
quote:
Originally posted by lilBuddha:
Decaying wood emits mostly methane whilst burning emits CO2. Both are greenhouse gasses, but decay releases at a much slower rate.
On the flip side CH4 is a much more potent greenhouse gas than CO2.
As always, things are not always simple. About 20-25% of solid wood eventually decomposes (rate dependent upon a whole host of variables such as temperature, soil microbes and acidity). In anaerobic conditions (eg landfill) over half the carbon released will be methane. In aerobic conditions (eg: in the litter layer of a forest floor) the proportion of methane released is much lower - with a lot of the carbon ending up in the body tissues of fungi, insects and other forest plants. So, burning waste wood probably has a lower greenhouse impact than burying it in landfill. It's probably a close balance whether it produces a lower greenhouse impact than letting it decompose on a forest floor.
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Don't cling to a mistake just because you spent a lot of time making it.
Posts: 32413 | From: East Kilbride (Scotland) or 福島 | Registered: May 2001
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irish_lord99
Shipmate
# 16250
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Posted
The problem with the solar panel-electric heat combo is that there is less sunlight in the winter and the upfront cost is very prohibitive.
Personally, I like what my family is working towards: an ultra efficient house, wood burning stove, and about ten forested acres to selectively harvest from.
Preserving that ten acres, in my mind, should more than compensate for the greenhouse gasses from the two chords I'll burn through my ultra efficient, epa certified wood stove.
Of course, that's expensive too, but I don't have to pay it all up front.
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"There are three kinds of lies: lies, damned lies, and statistics." - Mark Twain
Posts: 1169 | From: Maine, US | Registered: Feb 2011
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RuthW
liberal "peace first" hankie squeezer
# 13
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Posted
quote:
Originally posted by irish_lord99:
The problem with the solar panel-electric heat combo is that there is less sunlight in the winter and the upfront cost is very prohibitive.
Depends where you live. There is less sunlight in the winter here in southern California, but there's still plenty, and solar power is getting cheaper all the time. One city out in the desert, Lancaster, even mandates solar power for all new home construction. (And yes, before you ask, they do need heat in the desert -- it gets pretty chilly in the winter.)
Posts: 24453 | From: La La Land | Registered: Apr 2001
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mr cheesy
Shipmate
# 3330
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Posted
quote:
Originally posted by Alan Cresswell:
It's probably a close balance whether it produces a lower greenhouse impact than letting it decompose on a forest floor.
Sorry, this is utter rubbish for two reasons:
1. Wood is composed of carbon held in different forms. A large amount of it is held as lignin, which are extremely resistant to decomposition. So even over long (decades/centuries) it is possible to chemically find the remains of wood on the forest floor and in the soil as organic matter. In contrast, when wood is burned - hopefully in the most efficient way possible - all of the carbon is released as carbon dioxide. So burning wood is always going to be worse than allowing it to decompose on the forest floor. If wood is burned inefficiently producing smoke, it is going to be a lot worse.
2. And more importantly, the issue with greenhouse gases in the atmosphere is one of absolute concentration not just balancing equations. It is true that as the trees grow they take in carbon which is then released as they decompose or burn. But burning releases in a moment the carbon that has been taken up during a lifetime, so the absolute amount of carbon in the atmosphere increases unless there are sufficient trees growing to take up the C as it is being burned. It is therefore fairly obvious that you'd need a lot more trees growing than are being burned given the relative speed of carbon release via burning and the relative uptake of carbon via growth. An oversimplistic one tree growing for each tree harvested isn't going to help. Compared to the carbon release from burning, decomposition is always going to be slower and is always going to be less of a source of greenhouse gases.
This is why wood decomposition does not feature in any of the calculations of greenhouse budgets.
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arse
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Boogie
Boogie on down!
# 13538
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Posted
quote:
Originally posted by irish_lord99:
The problem with the solar panel-electric heat combo is that there is less sunlight in the winter and the upfront cost is very prohibitive.
My brother heats two large houses (plus all other electricity needs) with solar panels and a modern wood burning boiler.
(Granted, he has his own wood to clear and coppice)
But his solar panels work all year round - even in this rainy winter. Producing plenty for two families and, in the summer, selling back to the grid.
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Garden. Room. Walk
Posts: 13030 | From: Boogie Wonderland | Registered: Mar 2008
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mr cheesy
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# 3330
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Posted
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Originally posted by Boogie:
But his solar panels work all year round - even in this rainy winter. Producing plenty for two families and, in the summer, selling back to the grid.
And, if he is part of the crazy British solar feed-in tariff, he'll be paid for all the solar electricity he produces, even if he has appliances going which use it.
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arse
Posts: 10697 | Registered: Sep 2002
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Soror Magna
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# 9881
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Posted
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Originally posted by irish_lord99:
... Personally, I like what my family is working towards: an ultra efficient house, wood burning stove, and about ten forested acres to selectively harvest from. ...
I'm sure your 10 acres are absolutely lovely, and they're a tremendous carbon sink, but that's not a scalable solution. Seriously: 10 ACRES to heat a single family's house? With respect, I don't think energy efficiency is the main reason you want 10 acres of land. Just for starters, you could power 999 additional homes if you put a solar power plant on your ten acres instead.
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"You come with me to room 1013 over at the hospital, I'll show you America. Terminal, crazy and mean." -- Tony Kushner, "Angels in America"
Posts: 5430 | From: Caprica City | Registered: Jul 2005
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Alan Cresswell
Mad Scientist 先生
# 31
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Posted
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Originally posted by mr cheesy:
quote:
Originally posted by Alan Cresswell:
It's probably a close balance whether it produces a lower greenhouse impact than letting it decompose on a forest floor.
Sorry, this is utter rubbish for two reasons:
That's what I get for posting too early in the morning with insufficient coffee. You are, of course, right on both counts.
I was trying to get somewhere with the end of that paragraph, but even I can't quite work out what it was! I think at the back of my mind I was comparing burning wood to fossil fuels. Over which there is no real comparison - if you have to burn something, burn wood. Coppices will recover the lost carbon in a few years, if you're felling trees then they will regrow in a few decades, coal and oil will regenerate in millions of years.
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Don't cling to a mistake just because you spent a lot of time making it.
Posts: 32413 | From: East Kilbride (Scotland) or 福島 | Registered: May 2001
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mr cheesy
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# 3330
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Posted
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Originally posted by Alan Cresswell:
I was trying to get somewhere with the end of that paragraph, but even I can't quite work out what it was! I think at the back of my mind I was comparing burning wood to fossil fuels. Over which there is no real comparison - if you have to burn something, burn wood. Coppices will recover the lost carbon in a few years, if you're felling trees then they will regrow in a few decades, coal and oil will regenerate in millions of years.
Mmm. I'm not even sure about this statement.
Imagine a situation where it was possible to replace all fossil fuel use with wood (it clearly isn't, but go with this).
Petroleum is very dense in terms of calories compared to wood, so one would need a lot of wood to produce the same amount of calories as the oil and gas currently.
For simplicity, let's assume that producing the calories from burning wood produces the same amount of greenhouse gases as burning fossil fuels.
So we're imagining cutting down a very large percentage of big trees on the earth's surface. These trees are therefore no longer growing and no longer taking in carbon in growth or locking carbon into the soil sinks.
Burning wood is producing the same amount of carbon in the atmosphere as burning oil, but there are fewer trees (even if we replace the deforestation with new saplings, clearly the young growth is not going to take in as much carbon as the old growth), so the end result is more carbon in the atmosphere.
Of course, things are a lot more complicated than this simple picture: petroleum requires a lot of greenhouse emissions just to get it out of the ground for one thing.
In reality we're in a mixed energy economy, and we need to try to avoid burning anything. Wood burning on a large scale can be justified in particular circumstances - such as burning fallen wood, burning short-rotation-coppice, burning crop residues etc - and the life cycle analysis often (but curiously not always) suggests that they're less emitting than using fossil fuels.
On a very small scale, burning a bit of wood in a very isolated place probably isn't going to make much difference to the global atmosphere. But by the same logic allowing some to burn peat or coal isn't either.
Scaling these things up is really hard - and hence we so often seem to make choices which prioritise convenience over real benefits.
In practice, the best thing we could probably do to help the climate would be to rely more on renewables and stick to using wood to make heritage items which are not thrown away in a hurry. Failing that, we could start burying fallen wood in peat bogs where it doesn't decompose or burn, but we'd have to bury a lot I suspect before it made an appreciable difference.
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arse
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Dafyd
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# 5549
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Posted
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Originally posted by mr cheesy:
Burning wood is producing the same amount of carbon in the atmosphere as burning oil, but there are fewer trees (even if we replace the deforestation with new saplings, clearly the young growth is not going to take in as much carbon as the old growth), so the end result is more carbon in the atmosphere.
The new trees are going to take in more carbon than the old ones take in, since the new trees are using proportionately more carbon to make trunks and branches etc.
Over the life cycle of the trees that you're using, burning wood will be carbon neutral. So the only thing you're looking at is start-up costs - the period when you're burning already existing growth without locking it up in new growth. But as I say, if you're replanting trees immediately upon cutting them down, I don't think that start-up cost is significant.
(The other potential advantage of industrial biomass as fuel is that if carbon capture and storage can be made to work it will sink net carbon.)
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we remain, thanks to original sin, much in love with talking about, rather than with, one another. Rowan Williams
Posts: 10567 | From: Edinburgh | Registered: Feb 2004
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irish_lord99
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# 16250
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Posted
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Originally posted by Soror Magna:
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Originally posted by irish_lord99:
... Personally, I like what my family is working towards: an ultra efficient house, wood burning stove, and about ten forested acres to selectively harvest from. ...
I'm sure your 10 acres are absolutely lovely, and they're a tremendous carbon sink, but that's not a scalable solution. Seriously: 10 ACRES to heat a single family's house? With respect, I don't think energy efficiency is the main reason you want 10 acres of land. Just for starters, you could power 999 additional homes if you put a solar power plant on your ten acres instead.
Well, it's true that the 10 acres is too much. Actually, with a super efficient home, 3.5 acres of woods ought to be enough. And that might be scalable with about 2.3 acres of inhabitable land per person in this world (according to a quick google search) if there's three or more to a household. Not everyone needs as much heat as we do in New England, and the colder areas are less inhabited. So I think it could be scalable.
We could do the solar farm, but:
I'd have to clear cut ten acres, destroying natural habitat and greenhouse gas fighting trees and vegetation.
It produces a lot of greenhouse gasses to build said solar farm: cement has to be brought in, cement has to be mined and produced, aluminum mounting rails have to be mined or recycled, then forged, extruded, milled and shipped. The panels have to be manufactured, raw materials sourced, etc. Lots of copper has to be mined or recycled...
The interesting thing about "going green" is just how much we have to spend and pollute to get there. Returning to simpler living and communion with the natural world is much better, IMO. In fact, having installed over a dozen such solar systems when I was in construction, I'm beginning to suspect that the "greenest" motivation behind their manufacture is Franklin, Grant, and Jackson.
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"There are three kinds of lies: lies, damned lies, and statistics." - Mark Twain
Posts: 1169 | From: Maine, US | Registered: Feb 2011
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Alan Cresswell
Mad Scientist 先生
# 31
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Posted
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Originally posted by Dafyd:
Over the life cycle of the trees that you're using, burning wood will be carbon neutral.
Some carbon cost if fuel for transport, chainsaws etc. But, also since combustion does not convert all the carbon in the wood to CO2 and CH4 some carbon will remain in smoke and ash particles (which can be returned to the woodland as a fertilizer).
Something like coppicing may not even have much of a lag time. The harvested wood needs to be stored for a while to dry out, during that time there will be some regrowth of the tree taking in carbon before the wood is burnt to return carbon to the atmosphere.
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Don't cling to a mistake just because you spent a lot of time making it.
Posts: 32413 | From: East Kilbride (Scotland) or 福島 | Registered: May 2001
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mr cheesy
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# 3330
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Posted
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Originally posted by Dafyd:
The new trees are going to take in more carbon than the old ones take in, since the new trees are using proportionately more carbon to make trunks and branches etc.
Sorry, that's just wrong. The rate of carbon accumulation increases with tree size.
And if you think about surface area, it isn't hard to see why. A small sapling might, maybe, double in size - and the amount of carbon it contains - in a year. But a large tree has a much bigger surface area to start with, and given that the thing grows outwards with a new ring of growth each year, it doesn't need a very large layer across the whole surface to be capturing a lot of carbon.
And anyway, young trees don't actually contain too much carbon, because it takes time for them to start growing the hard, woody material where most of the carbon is stored.
quote:
Over the life cycle of the trees that you're using, burning wood will be carbon neutral. So the only thing you're looking at is start-up costs - the period when you're burning already existing growth without locking it up in new growth. But as I say, if you're replanting trees immediately upon cutting them down, I don't think that start-up cost is significant.
As I mentioned above, this might be true (actually the extent to which it is true depends on the species) but it is irrelevant.
Imagine I've cut down a large tree and burned it and captured all of the carbon dioxide in a large balloon which I'm holding.
Let's say the tree has produced 1 tonne of carbon dioxide.
Now you've come along with a sapling that we can agree will likely store - net - 1 tonne of carbon over its life.
So I let go of my balloon. And you plant your tree. Let's say it contains 1kg of carbon when you plant it and by year 2 it has doubled in size.
If we look across 40 years, it is true that there is no net increase in the atmosphere. BUT right now, when climate change is happening, there is a net increase this year of 1t - 1kg (999 kg) of carbon.
Unless you plant 1000 trees for every 1 you burn (in this example), there is a current (ie here and now when the problem is being caused) increase in carbon in the atmosphere.
That is basically the flaw with any carbon capture schemes based on tree growth: you'd need many multiple times the number of trees growing than the amount you are burning.
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arse
Posts: 10697 | Registered: Sep 2002
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Alan Cresswell
Mad Scientist 先生
# 31
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Posted
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Originally posted by mr cheesy:
quote:
Originally posted by Dafyd:
The new trees are going to take in more carbon than the old ones take in, since the new trees are using proportionately more carbon to make trunks and branches etc.
Sorry, that's just wrong. The rate of carbon accumulation increases with tree size.
And if you think about surface area, it isn't hard to see why. A small sapling might, maybe, double in size - and the amount of carbon it contains - in a year. But a large tree has a much bigger surface area to start with, and given that the thing grows outwards with a new ring of growth each year, it doesn't need a very large layer across the whole surface to be capturing a lot of carbon.
Though that's largely correct, there are a couple of counter trends. One is that eventually a tree stops growing, and although it still takes up carbon to replace fallen leaves the carbon uptake significantly slows (still faster than a very young tree - but that young tree has a lot more potential future carbon capture). The second is that mature trees tend to block sunlight below the canopy, whereas young trees also allow a much more significant under-story (with the corresponding carbon capture in that part of the forest) - we need to look at entire forests rather than just individual trees.
I should add that neither of those counter trends completely cancels the gains from larger trees having more bark and leaves.
The confusion comes from the habit of some scientists to normalise data (sometimes it's appropriate, other times less so). If you plot annual carbon uptake per kg of tree then larger trees look worse - as said, carbon sequestration is a function (to first order) of surface area and mass of volume.
The best approach is to plant new trees on land that has been deforested already, at a relatively high density. Then selectively thin the forest at intervals to allow the older trees to grow to their maximum size. Then use as much of that wood harvested for long-term applications (construction materials, furniture etc) as possible. And, use very fast growing plants for fuel.
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Don't cling to a mistake just because you spent a lot of time making it.
Posts: 32413 | From: East Kilbride (Scotland) or 福島 | Registered: May 2001
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mr cheesy
Shipmate
# 3330
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Posted
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Originally posted by Alan Cresswell:
Though that's largely correct, there are a couple of counter trends. One is that eventually a tree stops growing, and although it still takes up carbon to replace fallen leaves the carbon uptake significantly slows (still faster than a very young tree - but that young tree has a lot more potential future carbon capture).
Yes, of course these dynamics are complicated: but it was once thought that young trees were taking in carbon at a rate that is greater than trees growing at maturity. But that's not the case.
... but as you say it is complicated because tree species are different and their behaviour is different and their carbon storage is different.
As I said in the OP, the ethics are not obvious because it depends exactly on what is being considered and what is being compared to what.
quote:
The second is that mature trees tend to block sunlight below the canopy, whereas young trees also allow a much more significant under-story (with the corresponding carbon capture in that part of the forest) - we need to look at entire forests rather than just individual trees.
That depends on the species. See this.
But yes, of course, it isn't just about the tree it is about the whole forest. But it is also about the way misleading information is being fed to people to make them believe that wood is carbon neutral.
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I should add that neither of those counter trends completely cancels the gains from larger trees having more bark and leaves.
Nope.
quote:
The confusion comes from the habit of some scientists to normalise data (sometimes it's appropriate, other times less so). If you plot annual carbon uptake per kg of tree then larger trees look worse - as said, carbon sequestration is a function (to first order) of surface area and mass of volume.
I don't think it is really the problem with scientist but more to do with the way data is being used to persuade people to invest in carbon neutral projects.
quote:
The best approach is to plant new trees on land that has been deforested already, at a relatively high density. Then selectively thin the forest at intervals to allow the older trees to grow to their maximum size. Then use as much of that wood harvested for long-term applications (construction materials, furniture etc) as possible. And, use very fast growing plants for fuel.
I don't really disagree with any of that.
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arse
Posts: 10697 | Registered: Sep 2002
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mr cheesy
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# 3330
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Posted
Also I should say that lifecycle analysis often seems to be able to prove that potential gains from certain activities are a lot less than it first appears. I've read several suggesting that things like short-rotation coppice and anaerobic digesters give far lower gains compared to using fossil fuels than might be expected.
This is often due to the costs of machinery and (in the case of anaerobic digesters) the need to throw in barley to get the fermentation working properly.
That said, I totally agree we should be focusing on technologies that have lower emissions that the fossil fuel alternatives. I guess I'm just saying we shouldn't get too carried away - usually these things have drawbacks and may still be contributing to the problems.
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arse
Posts: 10697 | Registered: Sep 2002
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Soror Magna
Shipmate
# 9881
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Posted
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Originally posted by irish_lord99:
...
We could do the solar farm, but:
I'd have to clear cut ten acres, destroying natural habitat and greenhouse gas fighting trees and vegetation. ...
The solar farm eliminates the need for the other 999 households to have their own 10 acres, thus leaving 9,990 acres of natural habitat. ...
quote:
... Returning to simpler living and communion with the natural world is much better, IMO. ...
What we really need is judicious and efficient use of our natural resources. Live on the interest, not the capital.
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"You come with me to room 1013 over at the hospital, I'll show you America. Terminal, crazy and mean." -- Tony Kushner, "Angels in America"
Posts: 5430 | From: Caprica City | Registered: Jul 2005
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Alan Cresswell
Mad Scientist 先生
# 31
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Posted
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Originally posted by mr cheesy:
Also I should say that lifecycle analysis often seems to be able to prove that potential gains from certain activities are a lot less than it first appears.
...
That said, I totally agree we should be focusing on technologies that have lower emissions that the fossil fuel alternatives. I guess I'm just saying we shouldn't get too carried away - usually these things have drawbacks and may still be contributing to the problems.
That's certainly true. Anything that replaces one fuel with another can sometimes be little more than window dressing. There's nothing particularly magical about burning wood rather than coal that automatically, in every circumstance, the better option.
If we're serious about reducing the amount of pollution we produce, then at the top of our list must be to cut down on burning stuff (either directly, or indirectly through electricity use). When we've reduced the amount we burn then looking at what we burn becomes the next step.
There is no "zero emission" option that allows us to use power without producing some pollutants (greenhouse gases and otherwise). Everything will be an above zero net carbon producer. The question is how low can we manage to get, and can we do enough other things (eg: plant forests just to let them grow) to mitigate the effects of our consumption?
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Don't cling to a mistake just because you spent a lot of time making it.
Posts: 32413 | From: East Kilbride (Scotland) or 福島 | Registered: May 2001
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