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Author Topic: Food vs Fuel?  (Read 42709 times)
heatherw
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« Reply #15 on: March 27, 2008, 11:23:38 PM »

If you lack a cave for the bats, a good substitute would be a pigeon loft.  Historically pigeons were used as a source of high grade fertilizer,  and in many parts of the world the practice continues.  We were in Turkey this summer and noticed many pigeon caves with ladders leading up to them, presumably for this very purpose.
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NickW
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« Reply #16 on: March 27, 2008, 11:36:08 PM »

If you lack a cave for the bats, a good substitute would be a pigeon loft.  Historically pigeons were used as a source of high grade fertilizer,  and in many parts of the world the practice continues.  We were in Turkey this summer and noticed many pigeon caves with ladders leading up to them, presumably for this very purpose.

Trouble is they eat your crops - unless of course your talking urban pigeans and the detritus they eat Undecided

Bats eat mossies - See that link I posted it showed a wooden bat roost on a farm in the USA - circa 1910. It said they got 4000lb of bat poo a year. Thats allot of mossies!
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Eleanor
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« Reply #17 on: March 27, 2008, 11:44:48 PM »

Here you go Eleanor - guano from bat roosts. Build your own roost and harvest their black gold!
http://www.soilandhealth.org/03sov/0302hsted/030212campbell/campbell%201-5.htm
Fantastic beasties really - they will convert all those midges, moths and mossies into valuable fertiliser.
Thanks Nick, just what I was looking for  Cheesy. You are just a big old softy really  Roll Eyes. I found a picture of you taken just outside the BatCave - who is that pulling your strings  Huh


* batman.jpg (44.33 KB, 240x408 - viewed 410 times.)
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Ivan
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« Reply #18 on: March 28, 2008, 12:33:13 AM »

Anaerobic digesters are under-rated. When you burn biomass you lose many of the trace elements (nutrients), whereas with biogas, you tend to just burn the hydrogen and carbon (as methane), leaving everything else behind (ok, maybe you lose a little sulphur, but that's about it)
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paul
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« Reply #19 on: March 28, 2008, 07:33:31 PM »

Yep, sunlight per sq m is finite.  But I wasn't thinking of a multi-storey car park type structure with some earth thrown in.  I was thinking more of a long narrow structure, long side facing south, high ceilings, glass sides and a lot of additional light reflected in by mirrors, white internal finish, tiered/terraced growing troughs.

Or what about all those urban flat roof tops above office blocks, or factory roofs (or should these be left for photovoltaics).

Or perhaps something similar could be done on the south facing sides of mountains,  mankind has been terracing mountain sides for thousands of years to grow produce e.g. olives, fruit etc but many are now abandoned, but now we have modern building method and materials including glass, I'm sure a lot more could be done than is at present.

We know how well crops can be grown in a protective environment e.g. green house, poly-tunnel, we could grow all our tomato/pepper/oranges et all instead of shipping them all over the world wasting more fossil fuel.

Also, if we all gave up meat, would we be better off?  Is meat an efficient form of food production?

Paul
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NickW
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« Reply #20 on: March 29, 2008, 01:12:50 PM »

Meat is a very inefficient form of food production. I have substituted much of the mean in my diet for pulses - which happen to be very cheap because they are often grown as much for their nitrogen fixing attributes.

The point about sunlight is it is finite. If you grow crops up a wall, there will be a shadow behind it that will not be as productive. Same principle with a high rise building - even if you can somehow get the sunlight into the interior.

As food prices rise in order to help fuel the worlds fleets of SUV's I can see more of people lawn spaces being converted into veg gardens

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Bob
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« Reply #21 on: March 30, 2008, 08:22:54 AM »

NickW,

I just had the time to read the bat link.  Why can't we write in that style?  Brilliant!  I'm now wondering about getting the little chaps to live near here.  In the summer we are infested by midges.  Some mornings they are dense enough to make you choke.  Do you have plans for the roost?

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kristen
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« Reply #22 on: March 30, 2008, 08:46:34 AM »

My vote would be for sunlight harvest in the desert.  Produce electricity, if it can be "piped" to far off lands, or Hydrogen or some other fuel of that type.

IMHO taking good agricultural land out of food production is nuts (as was set-aside).  Wheat price has gone up massively, and so have fertilisers [obviously they just got twice as expensive to make/mine</cynical> - although the demand has increased and it takes a while to bring a new phosphate mine on stream].

And where's that bloody 0% VAT on renewals equipment??
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NickW
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« Reply #23 on: March 30, 2008, 04:05:06 PM »

NickW,

I just had the time to read the bat link.  Why can't we write in that style?  Brilliant!  I'm now wondering about getting the little chaps to live near here.  In the summer we are infested by midges.  Some mornings they are dense enough to make you choke.  Do you have plans for the roost?




Id love to have a bat roost but I live in surburbia with a small garden. If anyone has a go at building one Id be interested to see / hear how it works. Smiley
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NickW
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« Reply #24 on: March 30, 2008, 04:13:41 PM »

My vote would be for sunlight harvest in the desert.  Produce electricity, if it can be "piped" to far off lands, or Hydrogen or some other fuel of that type.

IMHO taking good agricultural land out of food production is nuts (as was set-aside).  Wheat price has gone up massively, and so have fertilisers [obviously they just got twice as expensive to make/mine</cynical> - although the demand has increased and it takes a while to bring a new phosphate mine on stream].

And where's that bloody 0% VAT on renewals equipment??


Solar electricity from the deserts supplying europe is another fanciful unicorn. For a start if you pipe the electricity direct you have major transmission losses - 1.5% with HVDC and about 3% HVAC for every 100km. The investment in HVDC would be immense. There is also the security issue - solar resources in North Africa???

Conversion into fuels is possible but then you have conversion losses. Hydrogen is an awful fuel to handle so would need to be converted into methanol, methane or ethylene. An alternative is ammonia and use it to make fertiliser. However these proceses entail a variety of processes that involve compressing gases. You will need a major source of CO/CO2 to make hydrocarbon fuels. Hydrogen in the gas network - forget it, it will leak out like water through a sieve.

If your going to invest in solar - put the panels on roofs in the UK and do away with the transmission losses and security issues. At least that would provide some real jobs in the UK. We will need them as the ponzi economy dies.
« Last Edit: March 30, 2008, 04:27:33 PM by NickW » Logged

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NickW
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« Reply #25 on: March 30, 2008, 09:07:24 PM »

I dont know whether this is coincidential but Tescos was completely out of rapeseed oil. I would not be surprised if this is 'greenies' filling their cars with it.

Instead I had to buy sunflower oil which is a less healthy alternative for Sundays roasties!

If I get heart disease in 20 years I will know who to blame. Huh
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kristen
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« Reply #26 on: March 31, 2008, 06:47:29 AM »

>> There is also the security issue - solar resources in North Africa???

Same issues for politicians as being nice too, or blowing up, countries that have oil  wackoold
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northern installer
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« Reply #27 on: March 31, 2008, 09:54:02 AM »

[quote author=kristen link=topic=3032.msg27813#msg27813 date=1206863194


You will need a major source of CO/CO2 to make hydrocarbon fuels. Hydrogen in the gas network - forget it, it will leak out like water through a sieve.


[/


quote]So why not site a solar powered hydrogen plant adjacent to a natual gas turbine power station,and feed a methanol plant with the h2 and co2 produced?
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KenB
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« Reply #28 on: March 31, 2008, 11:06:31 AM »

NickW, List,

With the weather getting warmer, and the cost of road diesel rising about 1p per week, it is not surprising that some are tempted to start pouring new rapeseed oil into their tanks.

This would very quickly stop if they were to make rapeseed oil 1.20 a litre, and then it might make better economic sense to fry your roasties in diesel  Grin

A litre of diesel was 0.476p in southern China last week - about 4 hours work for the average factory worker, if they were able to afford the car to put it in.

How many minutes does the average UK employee (or even those on a minimum wage) have to work to buy a litre of diesel?

Fuel is priced still too low in the west, and if it is a declining resource, it would be better to introduce pricing policies that will either lead to its conservation, or allow an increase in investment in public transport to the point where that becomes a viable alternative.

It's hard to speculate where the price will go from here, but my guess is to expect to be paying 2.00 per litre before the 2012 Olympics.



Ken
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NickW
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« Reply #29 on: March 31, 2008, 12:29:56 PM »

[quote author=kristen link=topic=3032.msg27813#msg27813 date=1206863194


You will need a major source of CO/CO2 to make hydrocarbon fuels. Hydrogen in the gas network - forget it, it will leak out like water through a sieve.


[/


quote]So why not site a solar powered hydrogen plant adjacent to a natual gas turbine power station,and feed a methanol plant with the h2 and co2 produced?



That is an option where there is a need to burn a fossil fuel but then it makes more sense to use the electricity locally and export the gas.

I once did a fanciful bit of maths looking at wave power in South Australia. The potential is huge - technicially something like 12000twh per annum. Anyway using the electricity to split water you also have a pure source of oxygen. Use this to combust coal and you have a pretty concentrated source of CO if you get the fuel / oxygen mix right. CO is the perfect feedstock for making methanol.

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