Atomic Weed
Nick the Seed
And wakeup just after you have peed.

Posted By: renewablejohnnot getting the point that plants actually grow better under shade conditions

Is that all plants or just some plants. Is it possible that there is an assumption that reducing sunlight on some crops, maybe ones that grow is shady conditions naturally, can be extrapolated to all plants?
I have no idea from a brief read though of that report as to if the experiment was a one off or repeated many times. I suspect that it was a one off because there is no ANOVA or CHI Square values in the results, not even a T-Test. So hardly conclusive evidence that plants need less sunlight.

Posted By: SteamyTea

Posted By: renewablejohnnot getting the point that plants actually grow better under shade conditions

Is that all plants or just some plants. Is it possible that there is an assumption that reducing sunlight on some crops, maybe ones that grow is shady conditions naturally, can be extrapolated to all plants?
I have no idea from a brief read though of that report as to if the experiment was a one off or repeated many times. I suspect that it was a one off because there is no ANOVA or CHI Square values in the results, not even a T-Test. So hardly conclusive evidence that plants need less sunlight.

I have not tested with C4 plants but certainly with all the C3 plants I have tested I get the same result.

Similar results are documented all over the internet.

http://ofrf.org/funded/reports/Kelly_01s36.pdf

Isreal have taken it a step further by using multicoloured shading for pest control.

http://www.noble.org/ag/Soils/IsraeliAg/index.html

Well, if we're not talking biomass in general, but oil seed rape yield in particular, then I think you may be right, but the yield (in terms of energy per ha) is low for rape, as we've already shown, so may well still be lower per ha than some other biomass plants even with a multi layer vertical piped light arrangement. The advantage of rape may be that it grows on a wide range of soil types and tolerates drought better than many high biomass growth rate plants, I believe.

I'd have thought it'd be tricky to do, practically, plus the investment in terms of light pipes etc would be very high, so I think the key question would be "would it be worthwhile?". The capital cost of covering millions of ha with some form of stacked growing system with light pipes, which is what would be needed to meet even current demand, would be extremely high.

If we're intent on pursuing biomass energy on a large scale, then it would probably be more economic to look at aquatic biomass, as we could potentially "farm" large areas of the ocean if we developed the right techniques. That raises other ecological issues though, and would no doubt be an international hot potato when trying to reconcile all the various special interest groups around the world. Maybe re-flooding places like the Aral Sea and turning them into large algae farms might be an option.

As an aside but connected:
http://www.sciencedaily.com/releases/2011/09/110925211543.htm

<blockquote><cite>Posted By: renewablejohn</cite>Energy yield for OSR is only low in your assumption of only having 1 tonne of oil per hectare at say 37GJ/t when in reality crops are now yielding 5 tonnes per hectare at an oil extraction rate of 0.4 per tonne thats 2 tonne of oil per hectare as well as 3 tonne of mash at 15 GJ/t and 2 tonne per hectare of straw at 15GJ/t plus 0.5 tonnes of honey at 14 GJ/t and finally 1 tonne of following year wheat at 16GJ/t. So by my calculation 1 hectare of OSR is equivalent to 173 GJ/hectare which is far better than SRC. The real gain would be in harvesting 2 crops per year instead of 1.</blockquote>

I'm not arguing that peak yields can be higher than the figure I quoted (which came from a reputable source) but I am arguing that average yield (which is what really matters in terms of land area required) will be very much lower than the peak figures being bandied around. All of us who have farmed the land have seen this, year in, year out; we have good years and bad years. The hay price around here is a good example of this, it's around double that from last year as the first cut was either non-existent or very poor.

If we're planning on biomass/biofuel as a major part of our energy provision (assuming we had anything like the available land mass) then we need to ensure security of supply. This means that we have to plan on average crop yield over vast areas, not the peak yield obtained under optimum conditions.

We can store in good years, to bolster bad years (up to a point) but that still means the average has to meet our average demand if it is to come close to making it secure and reliable as a fuel source.

A few lock-ups in Peckham should cover it... %-P

And amongst the first to get looted!

So according to the chart on slide 10, biomethane offers the best solution at 6 kWh.m^-2.y^-1
Would not PV, at around, 100 kWh.m^-2.y^-1 offer a better solution. If you want to store some of that by using really old technology(like lead acid batteries), it still has to be a better use of land.

Tried three times but can't get that link to work!

So will Oil Seed Rape grown when 250 kWh.m^-2.y^-1 hits the Earth instead of nearer 1000.
What is the Northern limit, or altitude limit for Oil Seed Rape?
And for that matter what is the temperature range that it can grow in because if you cover that much land in artificial shading you will change the climate regime there.

<blockquote><cite>Posted By: renewablejohn</cite> As JSH was making out with the energy content of rape oil ignoring the rest of the biomass content of the crop.</blockquote>

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.

I only quoted the rape/biofuel figure in direct response to a discussion on biodiesel, as you know full well. I went on (as you also bloody well know full well) to give figures for more effective biofuel crops and show the relative effectiveness of plants, PV and solar thermal energy extraction.

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.

As ST has pointed out, it is a far, far more efficient use of land area to use PV and even crude old lead acid batteries for energy storage (not that I'd advocate going down that exact route).

Now if only Knotweed could be burnt as biomass (as syngas or with ceramic filters to keep Brian happy): a dilemma becomes a public good!

Rgds

Damon

<blockquote><cite>Posted By: SteamyTea</cite>There is a lot of 'Public Good' next to me then<img title="" alt="" src="/forum114/extensions/Vanillacons/smilies/standard/cry.gif"></img>

I think it has to be burnt, but most people put it into the 'green waste' so that it can become compost. Anyone fancy a tonne of 'West Country Compost'?
Still at the rate rate it grows it must be sequestering CO2 well.</blockquote>

You've got to admire the way the Japanese Knotweed has evolved though, haven't you? It seems to be just about immune from pretty much anything we throw at it, will regrow from the tiniest fragment of rhizome, grows vigorously enough to punch through tarmac and survives pretty much anywhere.

I'd be interested in seeing what sort of conversion ratio it has; my guess is that it will be around that of some of the faster growing bamboo varieties and may not have much in the way of usable biomass or carbon sequestration capability. The idea of trying to farm it as biofuel fills me with dread, though, its reminiscent of Day of the Triffids.

<blockquote><cite>Posted By: SteamyTea</cite>Could let the French farm it, they seem to think they are the European experts on farming<img title="" alt="" src="/forum114/extensions/Vanillacons/smilies/standard/wink.gif"></img></blockquote>

Nice idea! I'm appalled at the way agriculture in large parts of France seems like something from 50 years ago. They have the luxury of much more farm land per head of population than we do and seem to do just fine with archaic farming methods and EU subsidies, coupled with a bit of robust direct action whenever there is a hint of reform from their government............