Renewable Energy: Biomass - a burning issue

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- CommentAuthorrenewablejohn
- CommentTimeOct 13th 2011
Posted By: JSHarris
Posted By: renewablejohnAs JSH was making out with the energy content of rape oil ignoring the rest of the biomass content of the crop.

If you're going to criticise, get your bloody facts right first and stop quoting me out of context in a futile attempt to discredit.

Whatever way you want to twist things, or try and discredit facts presented from multiple sources, there is no way that we have enough land area to grow enough biofuel to meet even a fraction of our energy requirements, simply because plants are pretty rubbish at converting sunlight into usable energy, full stop. Nothing we can do will change that basic fact.

JSH

Dont shoot the messenger just because he does not agree with your fag packet calculations.

You stated that to supply the UK energy needs from biomass would require 40,000,000,000 hectares of land. This is very much at odds with the article published above in respect of potential biofuel in Germany and Europe. The german figures being until 2050 75% of fuel consumption covered by biofuels and electro mobility require 2,800,000 of land to produce 15 million tonnes of straw and crop residues.
The european figures until 2050 more than 70% of fuel consumption in europe could be covered by biofuels and electro mobility require 40,000,000 hectares of land and 100 million tonnes of straw and crop residues.
Given the UK currently uses 8,000,000 in agriculture production there is no reason why we could not achieve a similar % of fuel consumption from biomass.
- CommentAuthorSteamyTea
- CommentTimeOct 13th 2011
John
Having had a second look at that Lackmann presentation, I note that there is a caveat on slide 4:
"*With strong efficiency strategy the huge increase of the total fuel demand predicted in the study of the European Commission "EU25- Energy and transport outlook to 20302 can be avoided"
On the same slide is the associated sub chart showing a 15% reduction between 2005 and 2050, not sure if he really meant to put TW instead of TWh, but it makes a difference, a huge difference.

Can you clarify that point please.
- CommentAuthorrenewablejohn
- CommentTimeOct 13th 2011
Posted By: SteamyTeaJohn
Having had a second look at that Lackmann presentation, I note that there is a caveat on slide 4:
"*With strong efficiency strategy the huge increase of the total fuel demand predicted in the study of the European Commission "EU25- Energy and transport outlook to 20302 can be avoided"
On the same slide is the associated sub chart showing a 15% reduction between 2005 and 2050, not sure if he really meant to put TW instead of TWh, but it makes a difference, a huge difference.

Can you clarify that point please.

Steamy

He has justified the strong efficiency strategy by using equipment like the Otag Lion which is already in the marketplace in both a gas and wood pellet version. Obviously one of the major planks in the German model is direct injection of biogas into the existing gas distribution grid. Beyond the grid is the option to use wood pellets.
As regards TW instead of TWh obviously its an error in drafting if you look at the previous slide for Germany it is TWh on both.
- CommentAuthorJSHarris
- CommentTimeOct 13th 2011
renewable john,

You seem intent on continuing to believe the physically impossible, perhaps because you make a living by convincing people to burn biomass for fuel, fair enough. The fact is that you are very selective in what you choose to present; you deliberately twisted the oil seed rape quote, knowing full well that I'd already presented figures for total biomass yield per hectare, rather just biomass derived diesel fuel per hectare, to support your minority view. You also presented my later, carefully calculated, figures as a "back-of-fag-packet" one, knowing full well that I'd only applied that epithet to the oil seed rape biodiesel comment,

The facts speak for themselves, no matter how you choose to try and display them. If you can produce evidence to show that the UK could meet all its energy needs, together with its food needs, from growing biofuels on the area of agricultural land we have available then please do so.

I'm also not sure whether or not you truly understand where biomass energy comes from, as you seem to be arguing that it is possible for plants to get energy from somewhere other than the sun (your point about high yield in shade made earlier).

The bottom line is that plants can extract around 5% or so of the available energy from sunlight and convert it into usable biomass fuel. That is, frankly, a crap conversion ratio and one that is easily bettered by pretty much every other direct or indirect solar energy collection method we have so far devised. Even if we could genetically engineer a biomass crop so that it gave the maximum photosynthetic yield possible of 11% then the yield would still be crap.

As I stated earlier, the UK energy needs are around 9.9 x 10^18 J per year and a hectare of a perfect crop with a high yield could give as much as 250MJ per year. There are 19,000,000 hectares of agricultural land in the UK, with about 8,000,000 hectares being used for arable crops. You don't need to be a rocket scientist to see that we simply have nowhere near enough land to grow all our fuel, no matter how someone wants to manipulate figures to make it seems otherwise.

As you're in the biomass fuel business, renewable john, tell us what your yield is, please? How many MJ per hectare do you get from your wood pellets? You must know these figures, being in the business.
- CommentAuthorrenewablejohn
- CommentTimeOct 14th 2011
<blockquote><cite>Posted By: renewablejohn</cite>

JSH

Dont shoot the messenger just because he does not agree with your fag packet calculations.

You stated that to supply the UK energy needs from biomass would require 40,000,000,000 hectares of land. This is very much at odds with the article published above in respect of potential biofuel in Germany and Europe. The german figures being until 2050 75% of fuel consumption covered by biofuels and electro mobility require 2,800,000 of land to produce 15 million tonnes of straw and crop residues.
The european figures until 2050 more than 70% of fuel consumption in europe could be covered by biofuels and electro mobility require 40,000,000 hectares of land and 100 million tonnes of straw and crop residues.
Given the UK currently uses 8,000,000 in agriculture production there is no reason why we could not achieve a similar % of fuel consumption from biomass.</blockquote>

JSH

Still not answered the question 40,000,000,000 hectares UK to 40,000,000 for 70% of Europe. Just restating the figures which led to this spurious figure does not justify that Mr Lackmann president of German Renewable Energy Federation figures which have been in the public domain for the last 5 years are incorrect.

Just for the record I do not make a living by convincing people to buy biomass but I am mentor to a lot of companies including a woodfuel supply company, a power generation company, a domestic micro chp company and a steam engineering company. All of which detracts from being a farmer.
Despite the articles referenced from around the world backing up my argument that plants can grow in shaded conditions and in particular circumstances as in the Australian field trials can produce better crops despite scientists predicting in lab conditions this would not be the case. The field trials even identified the fixation of nitrogen being the reason for this improvement.

At the end of the day the significance of Mr Lackmann article is three fold. First the realisation that any food produced can have an additional biomass energy residue which we should economically use. for example the production of virgin oil for food produces 15kWh of fuel but the residue produces 20kWh of fuel. Second The easiest way to distribute that biomass energy is by use of the existing national gas grid and beyond the grid to use biomass pellets. Third. The use of micro CHP plants in individual homes to get efficiencies of over 90% instead of the wasteful 25% or less from our current generating plant. To achieve this products like the Otag Lion are already on the market place giving variable 2kWe and upto 16kWh which are designed to link in with existing PV.
- CommentAuthorrenewablejohn
- CommentTimeOct 14th 2011
Posted By: JSHarrisrenewable john,

The fact is that you are very selective in what you choose to present; you deliberately twisted the oil seed rape quote, knowing full well that I'd already presented figures for total biomass yield per hectare, rather just biomass derived diesel fuel per hectare, to support your minority view. You also presented my later, carefully calculated, figures as a "back-of-fag-packet" one, knowing full well that I'd only applied that epithet to the oil seed rape biodiesel comment,

.

Must of missed the total biomass yield per hectare as I cannot find this on page 24 where the discussion started only my initial response stating that the "whole" crop needed to be taken into consideration for a meaningful discussion.
I was hoping it was a "back of the fag packet" calculation as it could then easily be discarded but if it was carefully calculated then reason needs to be found why it is so far adrift from that published by Mr Lackmann
- CommentAuthorJSHarris
- CommentTimeOct 14th 2011
I did answer it, actually, but it seems you didn't understand, or couldn't do the arithmetic......

How about my question about real energy yield, though?

You can make a very convincing argument for biomass simply by providing evidence. All we need is the energy per hectare per year figure for your wood pellets, nothing more. It is a figure you must have at your fingertips as its essential to understanding the basis of the business, every bit as much as an arable farmer has to know the yield from his crops or a beef, pork or poultry producer will know his feed conversion ratio. From that anyone here can quickly see whether or not its a sustainable method for meeting our energy requirements and you need make no further plea for the cause.

I'm going to put my neck out and suggest that your wood pellets give a net yield of significantly less than 200 MJ per hectare per year. Please feel free to counter this with your actual figures.

FWIW, the German paper isn't giving anything like the whole story, as I suspect you already know. Here are some easily verifiable facts for the UK, please feel free to give verifiable alternatives if you can find them:

1) The UK needs around 9.9 x 10^18 J of energy per year in total. This includes coal, gas, nuclear, oil and current renewables. The vast majority of it comes from non-renewable sources (including nuclear).

2) The UK has around 18,000,000 hectares of agricultural land, of which around 8,000,000 hectares are arable.

Anyone can easily work out how much energy we need to produce per hectare to meet our current needs purely from biomass, just divide the arable land area into the energy requirement. 9.9 x 10^18 J divided by 8,000,000 gives a figure of 1.24 x 10^12 J per hectare as the biomass yield requirement.

Similarly, anyone can also work out the arable land area needed to meet our current energy requirement from biomass, just divide the expected energy yield per hectare per year into the energy requirement. 9.9 x 10^18 J divided by 250 MJ gives a figure of 3.96 x 10^10 hectares (which I rounded to 40,000,000,000 hectares).

So, once we know your yield figure we will very easily be able to determine the arable land area required to make this a sustainable way of meeting our energy demand.
- CommentAuthorJSHarris
- CommentTimeOct 14th 2011 edited
Further to the above, I've just checked for secondary sources to refine the figures quoted.

The Department for Energy and Climate Change (DECC) 2010 figures (http://www.decc.gov.uk/assets/decc/11/stats/publications/energy-consumption/2324-overall-energy-consumption-in-the-uk-since-1970.pdf) show that UK total energy consumption was 218.5 x 10^6 tonnes of oil equivalent.

Wikipedia (http://en.wikipedia.org/wiki/Energy_density) gives the energy density of crude oil (as used in the DECC presentation method) as 46.3 x 10^6 J per kg, which is 46.3 x 10^9 J per tonne.

Using these figures the 2010 total energy consumption in the UK was actually 1.011655 x 10^19, somewhat higher than the historical figure of 9.9 x 10^18 that I used above, so more than 40,000,000,000 hectares would be required now.

It looks as if I was slightly out with the figure I quoted for arable land use. This has changed in recent years and the current figures from DEFRA (http://archive.defra.gov.uk/evidence/statistics/environment/land/download/xls/ldtb08.xls) shows that there was 18,509,000 hectares of agricultural land in total in 2005 (I quoted 18,000,000 earlier) and the proportion of that which is arable was 8,876,000 hectares, rather than the 8,000,000 hectare figure I originally quoted.

This doesn't change the outcome to any noticeable degree though. To meet the 2010 energy need with a biomass annual yield figure of 250 MJ/ha would require 40,466,200 hectares, slightly more than my estimate that used rounded figures from an old farming publication I had to hand.
- CommentAuthordjh
- CommentTimeOct 14th 2011
On a slightly different aspect of biomass, there's an interesting article about the history of fossil fuels and sustainability, with lots of detail about the Netherlands, in particular:

http://www.lowtechmagazine.com/2011/09/peat-and-coal-fossil-fuels-in-pre-industrial-times.html
- CommentAuthorrenewablejohn
- CommentTimeOct 14th 2011
Posted By: JSHarrisI did answer it, actually, but it seems you didn't understand, or couldn't do the arithmetic......

I can do the arithmetic thank you and can see your error in calculation.
- CommentAuthorSteamyTea
- CommentTimeOct 14th 2011 edited
Posted By: renewablejohnand can see your error in calculation

And the error is?
- CommentAuthorrenewablejohn
- CommentTimeOct 14th 2011
Posted By: SteamyTea
Posted By: renewablejohnand can see your error in calculation

And the error is?

Thats to easy

I think we need a suitable prize

How about some humble pie
- CommentAuthorJSHarris
- CommentTimeOct 14th 2011 edited
<blockquote><cite>Posted By: renewablejohn</cite>Thats to easy

I think we need a suitable prize

How about some humble pie</blockquote>

Absolutely. You have to prove that I'm in error though.

Best of all, why not just give us the energy yield for your wood pellets, in terms of J per hectare per year, then we can all see the reality of biomass as a viable sustainable fuel.
- CommentAuthorSteamyTea
- CommentTimeOct 14th 2011
?
- CommentAuthorJSHarris
- CommentTimeOct 14th 2011 edited
I've just been looking at what the biomass community have to say about energy yield per hectare and it seems that there are some sources quoting higher yields than I used. This source http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,163231&_dad=portal&_schema=PORTAL
quotes 167 GJ per hectare per year for willow, for example, although willow will only grow well in areas where there are fairly high levels of soil moisture available. Wheat would grow pretty much anywhere and wheat straw is quoted as being 62 GJ per hectare, higher than I would have thought to be honest. The same goes for woodland managed for sustainable wood production, a higher figure than I would have thought of 37 GJ per hectare per year. I'm guessing these may be optimistic figures, because they are being quoted by the biomass business itself (albeit via DEFRA).

Anyway, let's look and see how this changes the area of arable land needed to meet our current energy requirements.

Each of these biomass fuels would need the following areas of arable land in order to meet the 2010 figure of 1.011655 x 10^19 J per annum as our energy requirement:

Wheat straw at 62 x 10^9 J per hectare per annum needs 163,170,161 hectares (we currently only have 8,876,000 ha of arable land).

Sustainably managed woodland at 37 x 10^9 J per hectare per annum needs 273,420,270 hectares (we currently only have 2,840,000 hectares of woodland and only about half of it is sustainably managed - data from the Forestry Commission).

Willow (which won't grow in many areas because of its high water demand) at 167 x 10^9 J per hectare per annum needs 60,578,144 hectares (again, we only have 8,000,000 hectares of arable land currently available for growing food crops).

The UK total land area, for reference, is about 24,500,000 hectares, so currently arable farming takes up about 36% of it and agriculture as a whole takes up about 76% of it, leaving about 24% for habitation, wilderness areas etc.

Even using figures from the biomass business biomass doesn't come close to stacking up as a viable, sustainable, way of meeting our energy needs. Even if we planted every square metre of our available arable land with willow, found a way to persuade it to grow in dry and upland areas and decided not to grow any food crops at all, then we could still only meet about 14.6% of our energy needs, plus we would have no UK grown food or animal feedstock.
- CommentAuthorSteamyTea
- CommentTimeOct 14th 2011
Posted By: JSHarrisplus we would have no UK grown food or animal feedstock

Or anywhere to live, but that would solve the problem
- CommentAuthorrenewablejohn
- CommentTimeOct 14th 2011
Posted By: JSHarrisI've just been looking at what the biomass community have to say about energy yield per hectare and it seems that there are some sources quoting higher yields than I used. This source http://www.biomassenergycentre.org.uk/portal/page?_pageid=75,163231&_dad=portal&_schema=PORTAL
quotes 167 GJ per hectare per year for willow, for example, although willow will only grow well in areas where there are fairly high levels of soil moisture available. Wheat would grow pretty much anywhere and wheat straw is quoted as being 62 GJ per hectare, higher than I would have thought to be honest. The same goes for woodland managed for sustainable wood production, a higher figure than I would have thought of 37 GJ per hectare per year. I'm guessing these may be optimistic figures, because they are being quoted by the biomass business itself (albeit via DEFRA).

I suppose this will have to do as an admission of your error in your calculation quoting 250 MJ per hectare rather than 250 GJ per hectare bearing in mind miscanthus on the same table above is quoted at 225 GJ per hectare.

A mere factor of 1000 out in the calculation so land required on existing usage not 40,000,000,000 hectares but 40,000,000 which is of the same order of magnitude as the UK. If we can agree on that we can then start to have a meaningful discussion on the figures put forward by Lackmann for the German economy and the savings made in his assumptions to justify a biomass future for the German economy.
- CommentAuthorJSHarris
- CommentTimeOct 14th 2011
<blockquote><cite>Posted By: SteamyTea</cite>Or anywhere to live, but that would solve the problem<</blockquote>

It would indeed!

I'd like to think that something like biomass could be a "magic bullet" that will solve our energy problems, but it can't make more than an extremely small contribution in reality, so small as to hardly be worth the effort of doing, especially when we can use the solar energy that falls on our land so much more effectively in other ways.

Would we trade food crops for fuel? Not very likely I would have thought.

Could we use all the wood from our woodland areas and make them all sustainable? Probably, but this would only meet 1% of our energy needs and would mean not using UK wood for construction, using it all for fuel. I doubt that we'd even get close to using all our woodland as a source of biomass, either, because much of it is difficult to manage and in harsh terrain with high extraction and transport costs.
- CommentAuthorJSHarris
- CommentTimeOct 14th 2011 edited
<blockquote><cite>Posted By: renewablejohn</cite>I suppose this will have to do as an admission of your error in your calculation quoting 250 MJ per hectare rather than 250 GJ per hectare bearing in mind miscanthus on the same table above is quoted at 225 GJ per hectare.

A mere factor of 1000 out in the calculation so land required on existing usage not 40,000,000,000 hectares but 40,000,000 which is of the same order of magnitude as the UK. If we can agree on that we can then start to have a meaningful discussion on the figures put forward by Lackmann for the German economy and the savings made in his assumptions to justify a biomass future for the German economy.</blockquote>

Its simply an alternative set of figures, one postulated by the biomass business and extremely optimistic in terms of yield (as the source readily admits). All farmers will know that yield varies greatly, not just from year to year but with location, nature of the soil, availability of water, average temperature etc, so there is no way that large scale biomass growing in the UK could hope to come close to those figures.

If you can get miscanthus to grow over much of the UK at that rate you're doing well! Its a crop that grows at that high rate in tropical and sub-tropical climates. UK growth estimates are around half that yield, plus it will only grow in limited areas in the UK.

Anyway, even using those optimistic figures we still need far, far more land than the whole of the UK land mass in order to meet our energy needs, so it still doesn't make any sense as a solution.

Also, I note that you still haven't given the yield for your wood pellets. Please don't be coy, some enquiring minds want to know just how much net energy per hectare per year your product can give. Once we have that figure we can see how your premise of biomass being a sustainable solution to our energy needs stacks up in reality.
- CommentAuthorrenewablejohn
- CommentTimeOct 15th 2011
Posted By: JSHarris
Posted By: renewablejohnI suppose this will have to do as an admission of your error in your calculation quoting 250 MJ per hectare rather than 250 GJ per hectare bearing in mind miscanthus on the same table above is quoted at 225 GJ per hectare.

A mere factor of 1000 out in the calculation so land required on existing usage not 40,000,000,000 hectares but 40,000,000 which is of the same order of magnitude as the UK. If we can agree on that we can then start to have a meaningful discussion on the figures put forward by Lackmann for the German economy and the savings made in his assumptions to justify a biomass future for the German economy.

Its simply an alternative set of figures, one postulated by the biomass business and extremely optimistic in terms of yield (as the source readily admits). All farmers will know that yield varies greatly, not just from year to year but with location, nature of the soil, availability of water, average temperature etc, so there is no way that large scale biomass growing in the UK could hope to come close to those figures.

If you can get miscanthus to grow over much of the UK at that rate you're doing well! Its a crop that grows at that high rate in tropical and sub-tropical climates. UK growth estimates are around half that yield, plus it will only grow in limited areas in the UK.

Anyway, even using those optimistic figures we still need far, far more land than the whole of the UK land mass in order to meet our energy needs, so it still doesn't make any sense as a solution.

Also, I note that you still haven't given the yield for your wood pellets. Please don't be coy, some enquiring minds want to know just how much net energy per hectare per year your product can give. Once we have that figure we can see how your premise of biomass being a sustainable solution to our energy needs stacks up in reality.

JSH

Obviously you dont agree with the figure of 40,000,000 hectares so theres no point in having the debate.

Just for the record if you actually look at the biomass report they do not admit that the figures are extremely optimistic in reality there all very pessimistic as they do not include energy from the residual crop unlike the lackmann study.

I dont understand why your obsessed with current UK energy consumption when everybody else realises that we are the most inefficient generators in Europe using dinosaur power plants venting there waste heat to atmosphere. Dont you think it rather ironic that for the current UK usage you calculated above requiring 40,000,000 hectares Lackmann is proposing with the same area of land we have the capability of providing the whole of Europe with 70% of its energy requirements.
- CommentAuthorBrianwilson
- CommentTimeOct 15th 2011
Press report today details study on wood -burner use carried out by Broseley fires . â€œOwners of wood-burning stoves are using old wellington boots, soiled nappies and even dead livestock as alternative fuels due to rising cost of logsâ€. â€œWe asked our distributors and installers to tell us what customers were burning in their stoves, answers dirty nappies, plastic bottles, old wood pallets, broken furniture, unwanted shoes and clothes. Dead lambs and chickens, telegraph poles and railway sleepers, whisky barrels and newspaper briquettesâ€.
Having calculated DECC decision to raise biomass emissions limit for particle and NOX pollution will create additional basic air pollution equal to 18,772,000 diesel vehicles each travelling 20,000 km per year will now go away and bang my head against wall!!!!. :cry
- CommentAuthorSteamyTea
- CommentTimeOct 15th 2011 edited
Posted By: renewablejohnObviously you dont agree with the figure of 40,000,000 hectares so theres no point in having the debate

There is every reason to have the debate to show the nature of the problem and work towards a solution. The solution will be energy reduction and not a reliance on burning biomass, no matter how effective the technology.
I agree that we could improve our generation efficiency by using some CHP, but it will only be in specialised niches and not a major player for the foreseeable future.
What could be achieved with political will and financing is replacing all of our old coal fired with gas/nuclear, the technology exists and is well understood and the infrastructure is already there (unlike for large scale solar and wind). Security of supply becomes an issue, but we have been down that route before in the early 80's and seemed to survive. There would also be a measurable improvement in emissions.

Have you actually got any yield figures for your biomass? Any figures will do, MJ, kWh, Mass, % of sunlight. Without hard data decisions cannot be made. Claire Granier and Catherine Liousse, two French researchers, have recently looked at the data behind emissions for the IPCC. This incorporates biomass as well as fossil fuels, which are just very old biomass (some natural gas may be geological) and really highlights the main problem with biomass, it takes a long time to replace after combustion, worth looking at that data and seeing the scale of the problem facing us all.

I have mentioned somewhere that it may not be socially acceptable for a small fraction of the population to be 'energy secure' by growing their own biomass and claim that they are the do-gooders, a contentious point I know in the free market that I support, but free market economics also hold true in all other areas of our lives, they are just harder to spot and model.
Some things do not scale well, small energy production is one of them when you take the whole lifecycle into account.
- CommentAuthorrenewablejohn
- CommentTimeOct 15th 2011
Brian

Maybe a bit of biomass gas will put us in the right direction.

http://www.marcogaz.org/events/downloads/Session2/0%20-%20ASUE_mCHP-Technology_State%20of%20the%20Art%20-%20Formanski.pdf
- CommentAuthorrenewablejohn
- CommentTimeOct 15th 2011
Steamy

I dont see CHP as a specialized niche certainly not at the micro scale outlined in the report I just quoted to Brian.

I see these micro CHP systems as a direct replacement for old gas boilers instead of a combi boiler. If we ever get RHI then they will be the boiler of choice as there already eligible for Fits (No I dont know how that works) The Otag Lion even links in with PV and has a 24 hour memory programme which predicts usage and regulates accordingly.
- CommentAuthorSteamyTea
- CommentTimeOct 15th 2011
John
I should have been clearer, I was thinking more large scale CHP. We have had Micro CHP for a few years now, if it was so good every replacement boiler would be that sort and there would be loads on the market.

So you got your yield figures for us to see yet? Without them we can't possible estimate how feasible co-generation is at the domestic level.
- CommentAuthorJSHarris
- CommentTimeOct 15th 2011
<blockquote><cite>Posted By: SteamyTea</cite>So you got your yield figures for us to see yet? Without them we can't possible estimate how feasible co-generation is at the domestic level.</blockquote>

For such an advocate of biomass as the answer to our energy needs, I'm frankly amazed that John is being so coy about revealing the net energy yield per hectare per year for his wood pellets.

The optimistic figures from the biomass business I quoted earlier (they assume ideal growing conditions across the whole growing area, which is simply impossible to achieve in the UK) show that we would need:

273,420,270 hectares of sustainably managed woodland or,

60,578,144 hectares of land growing willow or,

163,170,161 hectares of arable land growing wheat straw

to meet our current energy needs. The UK only has a total land area of 24,500,000 hectares, of which only 18,509,000 hectares is agricultural land and only 8,876,000 hectares of arable land. Its not hard to see that biomass is simply not feasible as a primary renewable energy source; at best it might make up a very tiny percentage of our total energy requirement, even if we dramatically reduced energy consumption from present levels.
- CommentAuthorrenewablejohn
- CommentTimeOct 17th 2011 edited
Posted By: SteamyTeaJohn
I should have been clearer, I was thinking more large scale CHP. We have had Micro CHP for a few years now, if it was so good every replacement boiler would be that sort and there would be loads on the market.

So you got your yield figures for us to see yet? Without them we can't possible estimate how feasible co-generation is at the domestic level.

Steamy

I think the problem with Micro CHP in the past has been the 1kWe output (whispergen distributed by BG and Eon) which is insufficient to meet any household needs. This new Otag Lion has a 2kWe output which they say accounts for over 90% of household needs and is a modulated output driven by demand. I am still getting to grips with the German but the brochures suggests that it has a smart meter facility of turning non essentials such as fridges and freezers on and off to maintain the load within the 2kWe output band using the grid as a last resort. It will also accept PV input and export any excess direct into the grid. Sounds to good to be true so the price will be extortionate.
As for yield figures there is no point having the debate based on unsustainable energy demand based on our current inefficient technology. Now if you wanted a serious debate around the Lackmann article that would be a different matter.
- CommentAuthorJSHarris
- CommentTimeOct 17th 2011
<blockquote><cite>Posted By: renewablejohn</cite>As for yield figures there is no point having the debate based on unsustainable energy demand based on our current inefficient technology.</blockquote>

Really? Even today's yield figures would be a useful baseline with which to compare the relative performance of different renewable energy schemes.

For example, we know the yield of PV systems at present, and these are likely to improve in future too, so it would be useful to see how wood pellets compare now, too.
- CommentAuthorrenewablejohn
- CommentTimeOct 17th 2011
JSH

What on earth is your problem with discussing the Lackmann article. His proposition is that 75% of German energy can be generated with the appropriate technology using 2.8 million hectares of biomass. Given that Germany is a higher user of energy than UK, on a pro rata basis it would require 1.8 million hectares of biomass to produce a similar 75% proposition in the UK. If you assume food crop residuals account for 50% of whole crop energy content (see Lackmann graphs) then 3.6 million hectares of food crops would need to be grown for which we currently have 8 million hectares of arable land.
- CommentAuthorJames Norton
- CommentTimeOct 17th 2011
...can some one fill me in on this Lackman business as I can't be arsed to read 750 pages...!

J

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