[PVPost] Energy from wood

[PVPoster1]

[This is an edited re-post of a topic that existed before the forums were hit by a virus in June 2005. Please feel free to add comments at the end, however if you are reading this soon after it was posted, it's likely that more old' replies will be added in the next hour or so and therefore please wait before replying a) to see if your point will be covered and b) to let the original sequence of posts make sense. Thank you]

Here's some links:

http://www.econergy.ltd.uk/

http://www.britishbiogen.co.uk/bioenerg ... safuel.htm

http://www.peninsulapower.net/


I think that this form of generation will undergo a huge rebirth in the next ten years or so. There's so much 'waste' wood about that up to 1MW of capacity will need to be installed in a given area (typically 20mile radius) before energy crops can compete on price. From January 2005, wood can no longer be sent to landfill.

Regards,
DJ

[PVPoster1]

This is all good stuff - as long as it's waste wood that's being burned.

If we start growing plants specifically to burn, then there's a risk of the energy profit dropping below 1, as farming can be very energy intensive.

[PVPoster1]

But not necessarily, presumably? Would locally grown biomass have an EROEI less than 1?

On a related note, does anyone know how much land it would require (roughly) to provide for the UK's heating needs using, say, efficient wood-fired boilers?


Peter.

[PVPoster1]

Yes, not necessarily. But I thnk there would be a risk of it. There would need to be a careful planning and energy measurement exercise.

There's also the scale thing. We're used to economies of scale"" where bigger is cheaper but bigger is often also more energy intensive - it's only cheaper because energy costs less than the people (or whatever) it replaces. So if we're talking about people walking down to the woods to collect stuff to burn to heat their homes that's one thing. But if we're talking about a big mechanised farming scheme to produce wood to burn in a power station then that's another...

[PVPoster1]

Presumably, the calculations have been done somewhere?


I think that generally there?s a big question about which way we want to go:

Big centralized, presumably nuclear, power stations (though some big wind farms might fit this, especially the off-shore ones);

Or small, decentralized renewables.


I can imagine that governments would prefer the former, because it?s difficult to control the latter. But there is the question about the latter, which I think you?ve posed elsewhere, of whether small, decentralized renewables are able to reproduce themselves. I?d guess that PVs won?t, but at least some form of wind power would, along with biomass, etc.


Peter.

[PVPoster1]

I read an article recently where coal-fired power stations are being combined with wood-pellets to reduce the fossil-based proportion of CO2 emitted.

[PVPoster1]

TIMBER HAS A PRETTY GOOD ENERGY PROFIT RATION _ see
http://www.csiro.au/index.asp?type=medi ... diaRelease

Tropical trees are better than temperate, and it is better to use the nuts and not cut the tree down - better EPR and better sequestration of the carbon.

Sololeum

[PVPoster1]

I have a concern that widespread adoption of wood as a domestic fuel would encourage further significant deforestation - and I don't believe thats something the UK can afford.

Wood has lots of benifits but (and correct me if I am wrong) wood for burning only comes from either
1) UK trees cut down especially for fuel
2) Waste wood recycled from other activities
3) Imported timber (either waste or fresh)

In a post-PO UK, I would guess there will be less waste wood (less waste everything!) and what little there is will probably go to centralised power plants, although my guess is they will have a large appitie for such - I understand that wood provides less energy per ton than (say) coal.

We won't be importing much timber (much anything...), and what we do will have priority uses above fuel.

So that leaves chopping down native UK trees for fuel.

I'm sure the UK could tolerate the loss of some trees and I'm sure a residual level of waste wood from various processes (and trees that blow down etc) will be available for fuel but I have a big concern about widespread adoption of wood fuel in the UK - I fear it is not sustainable and the presence of any wood burning facility in the average home would just encourage joe bloggs to chop down the tree in his garden or the one in the park, when the winter is cold and the state (or market) supplied wood fuel is used up for the season.

It is for these reasons that I do not have, nor plan to, any wood burning facilities in my home.

Wood fuel seems popular with many posters on this forum - you guys have any comments??

[PVPoster1]

Obviously there is a danger of deforestation, but with biomass, unlike oil, you can also put back (i.e. replant) as well as take out. A wise policy would manage resources so that a constant stock (initially a growing one) was maintained.

Of course, if you have too many people trying to live off a finite resource, then there is a great chance of over-using it, but that applies to everything.

At what population level you could have sustainable biomass (with other options), I don't know. That would seem to be a very important question,


Peter.

P.S. There are a couple of techniques known as pollarding (roughly cutting back to the trunk) and coppicing (cutting back to the ground) . You take the bits which you cut off, and then the remainder resprouts. These techniques work well with species such as willow. There are also non-tree biomass groups which can be used such as Miscanthus species (called elephant grass, sometimes) and hemp which can provide good biomass. And their is aleurite's nuts, and possibly others.

P.P.S. I may have got confused between pollarding and coppicing.

[PVPoster1]

I totally agree with you on biomass vs fossil fuels - you can regrow one and not the other.

And your comments about pollarding and coppicing were most interesting (new to me!).

Even with quick growing varities, trees take quite a long time to grow, right?

During the winter, one wood stove providing heating and cooking might get by on only a couple of logs (I've little woodstove experience so someone can correct me one this...) per evening (and assuming no use during the day).

So how many days worth of wood can you get from a reasonable sized tree?

Maybe one of those huge trees in the best forest would supply a whole community for a whole winter ?

But how long did that tree take to grow, 50, 70 years?

If you plant TEN new trees for each whopper you cut down, will you not find yourself out of big trees and surrounded by sapplings in just a few years?

That sounds like Peak Wood"" to me !

Wood is a very valuable and versatile product and it's renewable nature is its greatest strength but I have real concerns about the widespread adoption of wood as a domestic fuel.

Since wood is so readily available I fear any well managed programme aimed at controlling wood use would not be able to prevent joe public chopping down the nearest tree he finds when he is cold.

This is a lot less likely currently since most houses have gas fires/heating and no easy means of burning wood - if you had a wood stove you would just fill it.

And I would suspect that MANY wood stoves used at once could produce localised air polution in the same way as early coal use did.

Figuring out the number that Peter mentions - the Uk population number that could live sustainably by wood - would be most intersting but I would guess it would be a very small figure but I also think it would be somewhat misleading.

A post PO Uk needs to use all means at its disposal to make the best standard of living for everyone this will likely use wood for some processes but I would contend that it should not include widespread domestic burning of wood.

[PVPoster1]

Some interesting points:-

- Most wood stoves these days are 'clean burning', and suitable for use in smokeless zones, as they have emissions very low in the particulate matter that causes pollution.

- There is currently a large overcapacity in UK wood resources. Many forests were planted years ago when wood fuel was in greater demand, and the shift to gas has meant that many of these forests have fallen into dis-management. Here's a very interesting and informative read on the subject:-

http://www.woodfuelresource.org.uk/

I've just done my first winter fuelled 100% by wood, and I'm very happy with the situation! Will be doing my first 100% solar summer in a few weeks too . . .

[PVPoster1]

- Most wood stoves these days are 'clean burning', and suitable for use in smokeless zones, as they have emissions very low in the particulate matter that causes pollution.

I didn't know that, thanks for the info.

- There is currently a large overcapacity in UK wood resources. Many forests were planted years ago when wood fuel was in greater demand, and the shift to gas has meant that many of these forests have fallen into dis-management.

Thats interesting, and cheery news - when do we ever find out a prime resource really is in oversupply!!

But I would hazard a guess that any such oversupply will be highly prized and very short lived, even in a post-PO UK that does NOT have widespread domestic use of food as a fuel.

My guess is contruction and essential power generation would (should?) get first call.

I further suggest that any huge oversupply of wood would be very short lived if we made domestic consumption viable - thats approx 22m homes in the uk!

Great that Andy and others can and do live 100% on wood - thats good work fellas, if I have no gas then I freeze!

How long would the North Sea oil fields have lasted (could still last) when used only for truely vital tasks (not private cars) ?

Forgetting import/export for a minute, widespread consumption of North Sea oil in private cars (and such) has made it last far less time that it might have, and we'll have to face the consequences of that.

Similarly I fear widespread use of wood will rapidly find us in the same situation, only no wood and no oil is worse than just no oil!

We might have to outlaw woodstoves and also the chopping down of trees.

Shocking and outrageous as that sounds - if we want to discourge potentially desperate and cold people from consuming the UK wood surpless in just one winter (anyone have a view on that?) then we need some disinsentives.

Perhaps the simple lack of available stoves to buy (or any money...) will prevent widespread adoption of the woodstove and prolong the apparent wood surpless ??

[PVPoster1]

You have a fair point, fischertrop - if everyone did it, there most certainly would be a problem.

The theme which seems to come up time and time again with this problem is that there is no single solution to the coming energy crisis. If and when it is resolved, it will be through a mixture of whatever technologies happen to be available.

Wood fuel suits me, and could suit a lot of other town- and city- dwellers, as local tree surgeons and the Council cut down so many trees every year that they are running out of places to dump the waste wood. So turning the whole lot into domestic fuel and giving/selling it to householders would kill two birds with one stone.

Many country-dwellers already use wood stoves, as backup heating at least. During a wood shortage, people like myself in towns may well end up burning the furniture - or whatever else will burn. I'm sure that in a crisis people would end up shoving all sorts of rubbish in their stoves to keep warm - but that's still something you can't do with a gas boiler.

If the use of wood fuel in the UK was maximised, it would free up other resources such as clean-burning fossil fuel plants and nuclear plants to generate electricity, which of course can be used to run small heaters.

I think that wood fuel will inevitably end up being part of the solution, but of course must be controlled so that we don't denude these islands of their forests.

There will be plenty of space for new forests to be planted soon - all those motorways and airports, for a start - not to mention huge supermarket sites and shopping parks. Get out the pickaxes and start a forest!"
1024 67 7 "Biofuels" 50040000000 17 "B" "I am surprised by the amount of waste there actually is. When I first got my stove I was worried about where to get the stuff. Now Im having trouble storing it. Im starting to think about using wood for cooking in the winter (there is just the price of an Arga standing in the way!!).

Examples : Today I picked up the beams from a house down the road that is being re-roofed. They were heading for a tip somewhere.

Along the road I noticed a loft conversion going on again with a skip full of beams. This is my next target.

Driving through the new Forset a couple of weeks ago I came across large scale burning in a Forestry Commision site. They had harvested the limbs that could be easily machine processed but were burning piles of timber each the size of a small house!! The logs were so big I couldnt shift them.

We really need a community effort to prepare wood for burning. It needs a team to hand cut timber into stove sized logs, and to have enough space to store it and dry it. It needs local organisation to find and manage waste wood for burning. I just dont see it happening.

I also plan to build a coal bunker which is not good news for the environment. The strange thing here is that I remember my dad demolishing our coal bunker when I was a kid (about 37 years ago) and now Im about to build one. Strange times.

Andy, your system sounds great - its where we want to be next year.

Pete M
- ears finely tuned to the sound of hammers and chain saws.

[PVPoster1]

Andy Hunt wrote:

The theme which seems to come up time and time again with this problem is that there is no single solution to the coming energy crisis. If and when it is resolved, it will be through a mixture of whatever technologies happen to be available.

I totally agree

Andy Hunt wrote:

I'm sure that in a crisis people would end up shoving all sorts of rubbish in their stoves to keep warm - but that's still something you can't do with a gas boiler.

Very true

Andy Hunt wrote:

I think that wood fuel will inevitably end up being part of the solution, but of course must be controlled so that we don't denude these islands of their forests.

Controlled wood fuel use gets my full support

Andy Hunt wrote:

There will be plenty of space for new forests to be planted soon - all those motorways and airports, for a start - not to mention huge supermarket sites and shopping parks. Get out the pickaxes and start a forest!

No room for forest where the M1 used to be, its the worlds longest continuous potato plantaion!

Guest wrote:

We really need a community effort to prepare wood for burning. It needs a team to hand cut timber into stove sized logs, and to have enough space to store it and dry it. It needs local organisation to find and manage waste wood for burning. I just dont see it happening.

In the unlikely event the the Gov introduced controlled wood use, the local council might ask for volunteers to man the collection teams - I would guess they'd want licensed"" teams to avoid the widespread deforestation I so fear.

[PVPoster1]

Pete - I will actually be keeping a couple of bags of coal in storage every winter in case of emergency. It's just so energy dense that every lump gives a huge amount of heat. In the event of wood shortages etc, it would be my last resort.

Fischertrop - I actually work as an Energy Officer for my local Council in Bury. It's a temporary post, but I'm hoping to be made permanent next March.

I've already had meetings with a company from Wales called Egni, who specialise in 'vertically integrated biomass solutions' - which basically means setting up a timber station locally to process waste wood from the Council and local tree surgeons, and turning it into fuel for biomass CHP boilers which would run municipal buildings.

I currently provide a grant for householders who want to install renewable energy measures at home, which pays for the installation if the householder pays for the equipment. I'm currently looking at a scheme whereby the Council could provide wood fuel for people installing wood stoves/boilers at discounted rates. It might be possible for me to get the manpower/processing equipment paid for via Council Tax, as every Local Authority has legal obligations to reduce carbon emissions from both Council properties and also private properties (have you heard of the Home Energy Conservation Act 1995?).

So I'm hoping to really get things moving in a controlled fashion here in Bury next year. Bury MBC is a member of the Red Rose Forest too, so there is potential for expanding the scheme into neighbouring counties.