Green credentials of wood-burning stoves under attack

[Ratman]

?‍♂️ neiln might know tho

[openspaceman]

On 25/06/2018 at 23:10, neiln said:

the workings in this article are as poor as the one written above I'm afraid

 

http://www.dailymail.co.uk/news/article-5619215/Burning-green-pellets-filthier-using-coal.html

 and it doesn't matter if its 'scientific press' either

https://theecologist.org/2018/apr/16/hardwood-forests-cut-down-feed-drax-power-plant-channel-4-dispatches-claims

 

 

 

 I didn't notice any sensible workings

 

From a quick search it looks like large ocean shipping has an energy cost of about 0.11MJ(MegaJoules) per tonne per kilometre, What I don't know is whether this accounts for an empty return leg.

 

A tonne of wood pellets  has an energy content of around 18600MJ and I'll neglect the ~2.5% energy cost to make them.

 

Shipping from Florida to England is about 7000km so each tonne will have a fuel energy cost of 770MJ to ship it.

 

This is about 4.14% of the energy in the delivered pellets.

 

It does of course neglect the fact that the fuel oil  used in the ships' engines has more energy utility than the heat energy in the pellets.

 

Financially it's attractive because we have subsidies to burn wood, the americans  have no particular advantage to burn the wood  because there are no renewable incentives plus their gas price is much lower than ours  since fracking was brought online.

[neiln]

There are no sensible workings, its about as bad as the OPs article for badly presented 'facts'.

 

I think it is based on the shipping, the processing and i suspect mainly the fact that the wood is wet and its energy output is low, a lot of the wood burnt just turns that water to steam, hence a lot of carbon emission to atmosphere for no useful return.  I'm guessing though, as the facts aren't well presented.  Anyway, relate that to a wood buring stove and we can see, locally grown and processed wood, PROPERLY SEASONED, and air dried not kiln dried, is maximising the green credentials.  kiln drying, burning wet and shipping in from far afield all eat away at that green credential, and eat it quite quickly if some ar to be believed.  Fuel choice will definitely outway any green saving from a 'modern stove' pretty quickly.

 

We could go into how green the forestry source is too but its a hole that gets messy.  what I'm saying is, with all of this, its NOT a simple subject and its very difficult to determine X is greener than Y and by how much, and the OPs article is too simple to take the debate far at all, or to educate users, or potential users, on how to burn clean and green (green in a good for the world way, not wet wood, but you know that), but at least its chipping in to getting a debate going so its good overall (if a thinly veiled plug for 'buy a new stove' )

[openspaceman]

50 minutes ago, neiln said:

 

 

I think it is based on the shipping,

I had a stab at that

50 minutes ago, neiln said:

 

the processing

and that

50 minutes ago, neiln said:

 

and i suspect mainly the fact that the wood is wet and its energy output is low, a lot of the wood burnt just turns that water to steam, hence a lot of carbon emission to atmosphere for no useful return. 

we're discussing burning pellets, the fact that they are pellets pretty much guarantees they are around 10% mc wwb

 

I wasn't defending the trade just wondering where those articles got their idea that the carbon footprint was worse than coal. Of course the atmosphere doesn't distinguish whether the increased CO2 comes from gas, oil, coal or biomass. The hope is that if the biomass is harvested sustainably any CO2 produced in one year will be mopped up by the next, which is not the case for fossil fuels.

 

[Vespasian]

Heard on the news, (radio) that a minister was havin a go at Micheal Gove for wanting to ban the use of woodstoves..

 

No idea on the background of the story but it does suggest its been considered as an option..  My thoughts are its commin down the road sooner than people think..  

 

Its one thing burning wood in some out the way location like a farm, but having people stacking dirty woodpiles all over the property in towns and villages is another..  

 

I'll give it another year or two before a bans in place..

[Stubby]

9 hours ago, openspaceman said:

 I didn't notice any sensible workings

 

From a quick search it looks like large ocean shipping has an energy cost of about 0.11MJ(MegaJoules) per tonne per kilometre, What I don't know is whether this accounts for an empty return leg.

 

No way would a cargo ship " return" anywhere empty . Same with an HGV .

 

[BowlandStoves]

Any wood burning stove will only operate at maximum efficieny in terms out heat output and reduced emissions when burning dry wood.

[openspaceman]

16 minutes ago, BowlandStoves said:

Any wood burning stove will only operate at maximum efficieny in terms out heat output and reduced emissions when burning dry wood.

For various values for dry.

 

There is some evidence that bone dry/oven dry wood burned in a natural draught burner has increased particulate emissions. Not likely in UK or most other places where the equilibrium moisture content settles out above about 10% mc wwb (~17% in a dry shed in winter by me)

[BowlandStoves]

There is evidence to suggest that a moisture content of max 20% will maximise your fuel output and this should help reduce emissions as the wood would not be bone dry/oven dry.

 

What is you experience with your stove  @openspaceman

 

[openspaceman]

25 minutes ago, BowlandStoves said:

What is you experience with your stove  @openspaceman

I have two, one is a pellet stove which is one of the first batch we imported from US in around 2000, seldom used and an old 1980s jotul 602 which is getting past it's use by date, It is a basic metal box and doesn't compare with a modern offering for cleanliness, soon I'll have to bite the bullet and get a modern one that meets the new standards. I have recently constructed a glazed log store which I hope will increase seasoning rate and keep logs dry in the winter, having previously relied on an outdoor stack for 39 years.