Links[edit source]

  • Vinay Gupta: SCIM, Hexayurt, poverty, gupta option
  • Thomas Bjelkeman: back of the envelope, seawater greenhouses
  • Marcin: OSE wiki and blog
  • Appropedia and canaripedia
  • Dark Mountain
  • Reprap
  • Gunter Pauli: zeri, the blue economy, George Chan's dream farm
  • Complementary currencies
  • Smàri McCarthy: fablabs, democracy
  • Harrison Owen: open space technology
  • Edward de Bono: cort, six hats, lateral thinking

Some Questions[edit source]

I intend to organise a set of 300+ questions, compiled with help from maybe 30 specialists, and turn it into a free-content PDF booklet in 100 days or so. Maybe it will be out there before the official celebration of the Canary Islands' day, and maybe we can send a number of copies to a number of people, just so some data and possibilities may have a better chance to enter the conversations.

I think I can pose at least 50 questions myself, and answer a bunch of them at least in fill-in-the-blanks template form. I have contacts with a number of domain-experts who would let us have some answers. We can expand within that style, and see what comes up exactly.

Having a deadline is a good thing, too. Release early, sure. And maybe release often, but that's not my problem. ;-)

What are your questions?

Questions[edit source]

  • Some questions are more about facts. We'd like numbers and, if not, sensible estimates. If we don't know, we don't know, but the question is still worthy of some effort.
  • Some questions are more about exploring posibilities. But those posibilities carry the need to look at data: resources needed, people served, etc.
  • Many questions could be reformulated for different levels of land aggregation, as in how much water is used “per island”, and you can deal with that now or leave it for later.
  • Many questions can be reformulated, period. Please do so, maybe providing alternate ways to ask the same basic question. In the final document, the question may use a paragraph, followed by the more or less lengthy answer elicited by the question(s).

Water[edit source]

  • Where do we get our water from and what are the paths for water?
  • How much do we use for each function (including irrigating golf courses)?
  • How much fossil fuel do we use for our water (desalination, movement, others)?
  • What are the basic needs of water per person and per day? Per kilo of crop?
  • How much water is wasted, and where? What could be done about it?
  • What's the volume of water deposits at different levels (the sum of all homes; agricultural tanks; municipalities)?
  • Who owns the water, and the land where much of the water falls?
  • Would seawater greenhouses work? What are the factors and the data about those factors?
  • What are the laws and regulations and bodies regarding water?
  • Who are the experts in water in the Canaries? Where are they (professional contact only)?
  • What are other questions regarding water in the Canaries?

Food[edit source]

  • Where do we get our food from, what are the paths for food, and how much does it cost?
  • How much food do we grow here, and what are the inputs we use, and at what cost?
  • What's the seasonality of food, both in production and in consumption?
  • How far does our food come from, and what's the cost in terms of fuel and money?
  • How many people know how to grow food organically, and how long does training last?
  • How much land is available for growing food, and what are the features of that land?
  • How is the food growing (plants and animals) connected within itself and to the rest of the system (using food scraps for compost or animal feed, etc)?
  • What are the laws and regulations and bodies regarding food?
  • How does the price for organic and non-organic food compare at different times of the year?
  • Who are the experts in food in the Canaries? Where are they (professional contact only)?
  • What are other questions regarding food in the Canaries?

Energy[edit source]

  • How much energy do we use, and for what uses?
  • What are our energy sources right now, renewables or not?
  • What's the daily and monthly rhythm in the use of energy?
  • How much energy is stored at any one time, in tanks and batteries?
  • How much energy is used for transport, and how much is transported and at what speed?
  • What are the potential energy sources, with data? Wind maps? Renewable forest mass, algae mass?
  • Who are the experts in energy in the Canaries? Where are they (professional contact only)?
  • What are other questions regarding energy in the Canaries?

Others[edit source]

(maybe in groups, but always an “others”):

  • How much iron etc is there in our landfields, that would become our mines in the “unglobalised islands” thought-experiment?
  • What does our industry look like? Workshops? DIY clubs and networks?
  • What are other questions regarding the “unglobalised islands” thought-experiment?

Bjelkeman's seawater greenhouses for a bad pandemic[edit source]

Reply by Thomas Bjelkeman-Pettersson on October 14, 2008 at 12:04am

I did discuss this slightly offline with Lucas. Lets use some of the parameters he mentioned to make a “back of the envelope” calculation.

The need is:

  • 15 litres water / day / person
  • 2200 calories / day / person
  • 2 million people (Lucas lives in the Canary Islands).

A Seawater Greenhouse setup for vegetable production produces 1.2 litres / m2 / day. Which is consumed by the vegetable production in the greenhouse. You should easily be able to get a yield of 30 kg / m2 / year from the greenhouse. (Some greenhouse growers, under less ideal conditions are able to double this yield, but lets use that for now.)

So for simplicity sake, lets assume 0.25 calorie / g vegetables. For 2200 calories then you need 8800 grams of vegetables / day to meet your calorie requirement. The so called Gorilla Diet.

Lets supplement it with a little bit of fish, we are talking about an island nation. Lets say one fillet of white fish (154g) / person / day, that is 265 calories. a href=""> >

Add two potatoes 2x 136 g / person / day, which is 236 calories. (Not sure of growing potatoes on the island, but I think we can use the cool air stream in the shade tent behind the greenhouse for colder climate to do that.) a href=""> >

2200 - 265 - 236 = 1699 calories. If the remainder is vegetables then you need 6796 g vegatables. Lets say 6.8 kg / person / day.

Which shows that you probably will need to supplement with some avocados and nuts, maybe sundried tomatoes etc. but this is a “back of the envelope” calculation, so lets leave that for now.

For simplicity sake we will assume that all the vegetable yields are the same in the greenhouse for all vegetables. So one person needs 6.8 kg / person / day. 6.8 x 365 days = 2482 kg. Yield / m2 is 30 kg. Which gives 2482 kg / 30 kg/m2 = 82.7 m2 / person / year to grow the vegetables, lets say 83 m2 to make it easier.

1 hectare is 10 000 m2, so that feeds 120 people for one year with vegetables. So you need 2 million / 120 = 16 667 hectares of greenhouses, plus the space to grow the potatoes.

Lets do a sanity check on that. How much is that? Almeria in southern Spain has in the range of 25,000-30,000 hectares of greenhouses. According to one source (below) they only get about 9kg / m3 from their greenhouses (in 2000), but that is fairly typical for Almeria yield according to my sources.

Almeria is a huge exporter of vegetables. Think of it as about 1000 Euro / ton of vegetables. Do the math. It is a lot. Great income.

Ok, so the Canary Islands can become self sufficient in food if they want to, building a powerhouse of vegetable exports using only sustainable energy. The islands are pretty windy, so running window power stations for the power needed to drive the process in the greenhouse is possible. How much energy would be needed? Lets be conservative and assume 20 kW peak load per hectare for pumping power. 20 kW x 16700 = 334 000 kW = 334 MW. Which is 100 modern windpower stations at peak load. Not bad.

(The greenhouses perform a cooling function in the process of evaporative cooling which is about 250-400 kW / 1 kW of pumping power. That is a nice output, getting cooling power worth 250-400 times what you put in.)

Ok the water then?

A Seawater Greenhouse can output significantly more water than what the standard greenhouse will output, if we have access to cold water. The Las Palmas solution used deep water from nearby the island. a href=""> >

Lets assume you have access to 1000 meter deep water within three, four km of the coast. Then you can build a pipeline there and go get the nice 6-8 C water. This type of cold water will improve the water output from the condensers in the greenhouse significantly. Lets assume we get 10x more water out this way. So you get 12 litres / m2 greenhouse / day. That is 10 litres extra, that the greenhouse won't need for the food crops you are growing.

10 litres x 10000 m2 (one hectare) = 100 000 litres or 100 m3 water per hectare. 16 700 hectares will then produce 1 670 000 m3 water. Or 1,7 million m3 water.

2 million people use according to our assumption above 15 litres /day / person = 2 million x 15 = 30 million litres or 30 000 m3.

So our setup would produce more water than we need. In fact this is probably quite a good idea, as the pipeline and pumping to bring up that water would cost quite a bit.

How much? A pipeline being build in Curacau where I have been looking at the business case a bit.

That pipeline would cost about Euro 15 million to build. It is supposed to bring in water at about 500 litres / second. In one day that would be 43,200 m3. I am not sure, without having to take out the big calculator, how much that heat transfer that will give us the ability to condense. I would have to check that. But we are in the right ball park, I bet it is the right order of magnitude.

How much would the greenhouses cost to build? Well, the nice thing with them is that they are instantly profitable. As soon as you have one built it starts making money (ok so it takes a month or three for the vegetables to start maturing, but it is quick). So you can build something like this in stages and gradually prove the concept and be profitable at every step.

Did I say that it is easy to grow without using pesticides in he Seawater Greenhouse? Another synergistic effect. But that requires another story.

Was that the type of answer you were looking for?

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