Wave Power

Hinged cylinders anchored in the seafloor are pushed by waves, turning onshore turbines that create electricity (Orkney, Scotland)

This article was originally published with the title The Efficient City.

8 Comments

1. 1. scots engineer 01:58 AM 8/24/11

   When will the editors of SA get it, vertical farming is a delusion. Transport is not the problem, and if it was vertical farming would not be the answer. Present day trucks deliver 30 tonne loads at about 2.5 kilometers per litre of fuel, and freight trains and ships do even better. In contrast, most of the light crops require in a vertical farm with several floors would need to be artificial to acheive any reasonable output, and this would be of the order of a megawatt hour per square metre per annum. Even at electicity costs of 1 cent per unit ( kilowatt hour )the cost of the electricity alone would make it hopelessly uneconomic. Where are the monorails? In city centres where many buildings have many levels, people still enter and leave at ground level , or basement underground systems. One might think there would be a use for a transport network half way up. This would relieve some of the burden on the elevator system and improve building to building journey times. Underslung monorails crossing between buildings on cable stayed or suspension tracks could enter and leave buildings at any desired level. The top side of tracks could be enclosed pedestrian bridges. The improved access and evacuation ability would be helpful in the case of emergency.

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2. 2. scots engineer 01:58 AM 8/24/11

   When will the editors of SA get it, vertical farming is a delusion. Transport is not the problem, and if it was vertical farming would not be the answer. Present day trucks deliver 30 tonne loads at about 2.5 kilometers per litre of fuel, and freight trains and ships do even better. In contrast, most of the light crops require in a vertical farm with several floors would need to be artificial to acheive any reasonable output, and this would be of the order of a megawatt hour per square metre per annum. Even at electicity costs of 1 cent per unit ( kilowatt hour )the cost of the electricity alone would make it hopelessly uneconomic. Where are the monorails? In city centres where many buildings have many levels, people still enter and leave at ground level , or basement underground systems. One might think there would be a use for a transport network half way up. This would relieve some of the burden on the elevator system and improve building to building journey times. Underslung monorails crossing between buildings on cable stayed or suspension tracks could enter and leave buildings at any desired level. The top side of tracks could be enclosed pedestrian bridges. The improved access and evacuation ability would be helpful in the case of emergency.

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3. 3. Elegia in reply to scots engineer 10:03 AM 8/25/11

   What if the vertical farm were layered, as in the picture above, facing in a southerly direction & rotated once per 24 hr period to optimize exposure to the sun. And used mirrors?
   
   The thing about transporting produce over long distances isn't entirely the issue of fuel. For those of us who actually have eaten FRESH produce, picked this morning, but are usually dependent on produce picked before its time & artificially ripened (or just turned a ripe color with gases), designed to endure picking, packing & transport, rather than delivering flavor & nutrition... well, there's just no comparison. I'd rather eat my strawberries fresh.
   
   Maybe there isn't a way for vertical farming to work now, but new ideas get refined, once experimentation begins. Yes?

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4. 4. scots engineer in reply to Elegia 05:48 AM 8/26/11

   Hi Elegia - the physics is still against you. Crop yields are dependant on the quantity of light they receive whilst they are growing.In the case of the layered structure illustrated, the amount of natural light it could receive( without mirrors reflecting from nearby locations)would be no more than that of the outer surface laid flat, at best. This is obviously a lot less area than the total for all the various floors. Many vegetables and fruits are picked and into retail outlets in a matter of a few hours, or less. The dilemma facing the retailers is that fully fresh and ripe fruit and vegetables have a short shelf life and customers vary their shopping times at will.Satisfying customers whilst not having a problem of too much over ripe produce ( which does not sell so well ) would be an endless headache for retailers if there were not the means to extend shelf life ( refridgeration and selected varieties ). The mirrors you suggest would themselves occupy additional land, and would be mechanically complex to function over a large part of the day ( and therefor expensive and maintenance intensive). I admire your audacity in suggesting rotating a whole building to track the sun, but while it is probably possible to do so, the small increase in solar radiation you would collect as a result could never justify the large additional cost( especially as less than 10% of this radiation is converted into plant material).If you wish for produce that has been very recently harvested, there might be ways to organise it using the internet, but for it to work well, you the customer would have to commit to purchase further ahead.Growers would happily harvest in the best condition and couriers transport , but they would need to know that you were going to accept and pay for the goods.
   

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5. 5. Elegia in reply to scots engineer 09:48 AM 8/29/11

   Our planet is full of energy all around us, solar, wave, wind, both earth & water thermal differential. I see your point about the sun exposure. I remember when my former boss, normally a superb farmer, decided to rotate a strawberry crop to a field surrounded by tall trees. I thought to myself, "Huh?" Sure enough, the yield from that acre was sad & inadequate. Not to mention the battle with the deer!
   
   How about this then? Let's stop paving over all the best farmland! :D Let's turn the Los Angeles Basin & the Santa Clara Valley, just for two prominent examples, back into orange groves & fields & put the PEOPLE in vertical cities. If we designed them with people in mind, rather than cost, we might make them worth living in. I'd like to see cities that I could walk in, without inhaling fumes, cities with schools & shops I didn't have to drive to, or some sort of transport like the pod system that Gatwick (or is it Heathrow?) is launching.
   
   I could go on, but in fact, I've become especially cynical over the past couple of decades. I'll hold out some hope that humanity will find a way to stop crowding itself off the planet & live together. But not a LOT Of hope.
   
   :)
   
   Thank you for your thoughtful response.

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6. 6. scots engineer in reply to Elegia 02:47 AM 9/2/11

   Hi Elegia -thanks for your kind comments. People are ackward criturs and seldom content with what they've got. This discontent is not alleviated by many businesses depending on persuading them to buy more than they need. Like you I find this makes me more cynical than my idealistic youth. This is however important - probably the most important question - how do we set the ground rules for societies that allow for personal freedom whilst curbing run away greed ambition and unsustainable consumption? We have to acknowledge our vices as well as our virtues, and take genuine responsibility for our actions, and their consequencies. If acheived it will be no mean feat and will include reform of not just laws,but the systems that produce and operate these laws, and how they are enforced. Most people have a sense of fairness,( or rather when some scenario seems unfair,) and reconciling this on a day to day basis, cannot be totaly dependant on how somebody else in similar, but not identical circumstances decided in the past.As well as being educated to read write and count, people should be helped to practice the skills of judgement. They should realise from the out that getting it "right"is neither expected every time, or even possible, but with practice and honest appraisal, improves and the changes in societies, over time,should be immense.It could be called encouraging people to think for themselves and be less prone to accepting the opinions of those whose agenda is not reveiled.

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7. 7. pfhenshaw 09:21 PM 9/6/11

   Massive self-deception is what is going on here, or naked capitalism selling misguided social values... Those are not good choices.
   
   It's not just the marketing people who get so taken by their beautiful images they quite overlook the rudimentary facts of life. It's the whole community of sustainability experts too, enamored with their beautiful but mistaken solutions. It's just plain false to think cities as being low impact.
   
   The whole illusion of "green cities" is a result of cities being **high outsourced**, good at hiding their resource uses **elsewhere**. It's because the life blood of cities is their commerce, as well as the intensity of crowing a lot of high productivity people in a small area.
   
   Add to that that cities are the centers of finance where money is used to make money by multiplying resource use and impacts all over the world, and you start seeing the true picture. A city is the least self-sufficient kind of habitation there is.
   
   Scientifically you measure the impacts of a city by developing proxy measures for their total economic product. That's usually 8000btu/$GDP and .46kgCO2/$GDP. They are distributed fairly evenly per dollar because GDP is a measure of personal consumption and diverse personal consumption is going to be "about average".
   
   When you do that it erases a number of "now you see it now you don't" kinds of trick shell games with resource accounting that the green economy promoters seem completely fooled by.
   
   http://www.synapse9.com/SEA

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8. 8. Bill77 in reply to pfhenshaw 06:48 PM 9/8/11

   pfhenshaw, perhaps that is the way cities *are*, but does that mean that they have to remain that way? The current system basically forces the energy cost of a city-based business onto the employees, at least the lower-tier employees. The cost of city-living is higher, so lower-paid employees commute from cheaper cost-of-living areas. This makes the "city" appear more energy efficient than it is, because some energy cost has been shifted to the commuters.
   
   On the other hand, what is the alternative to densely populated cities? Suburban sprawl? It would seem that has it's own problems. Per capita, I bet that results in a lot more concrete that city living. For example, 1 million people living/working in a 10 square mile City vs 50,000 people living in a 4 or 5 square mile spawled city. The city's paved streets will be used by vastly larger amounts of people versus the wide, lightly-used streets connecting suburban McMansion subdivisions to each other and city services miles away.
   
   Why create a multi-level farm building, if it is more efficient to build multi-tier housing to free up more flat farm-land (i.e. more sun exposure and less paved land per capita)?
   
   It seems like the optimal city design has medium/high density affordable housing built around an inner-circle of high-density office space (i.e. high-rise) and services (supermarkets, clothing, electronics, etc). Add in safe, bicycle paths (perhaps bicycle-only "spokes" every 90 degrees on the inner-service-circle?). Build in light-rail / subway with a mix of passenger and cargo cars. For example, to maintain passenger flow, divert the cargo cars in the inner "service" circle to a separate unloading track.
   
   Reducing energy waste by reducing travel to work/services is definitely "green". Impotently trying to defy the laws of physics by building a multi-level farm building is a waste of resources.

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