Namibia to build 25 square km greenhouses!

[JoeReal]

The ultimate greenhouse yet. This is extraordinary in that it attempts to combine both energy and cash crop production literally under one structure. I hope they will succeed. Namibia approved this project and construction will begin this year. Each collector will cover 37.5 km2 (9,266 acres) area and generate 400 MW of electricity with 25 km2 (6177 acres) of that used as greenhouse area. Imagine, 6,177 acres of greenhouse that produces 400 MW of electricity. The chimney would be 920 ft diameter by 4,921 feet tall! A total cost of 600 Million Euros per greenhouse.

I could only imagine what kind of rarefruits I'm dying to plant inside these greenhouses! One important thing to note is that the vegetation inside this structure will increase its overall energy conversion efficiency.

There is no problem with windspeed as the chimney structure can be made strong and yet inexpensive. Moreover, the resonance problem with such a long tube can be solved by putting a lightweight spiral helix around the chimney to break or disrupt the lateral winds to prevent the resonance from building up, similar to the reason why a small wire is wound around your car antenna to prevent the whistling sound.


Here's how the basic tower operates:
Solar updraft tower - Wikipedia, the free encyclopedia

Here's the news that Namibia government approved building such green tower together with greenhouse area:
Solar tower sheds light on little-used technology

And here's the short Executive summary of the project:
GreenTowerGT - Short Executive SummaryGreenTowerGT - Short Executive Summary

[broli]

[JoeReal]

Some projects are economical and able to pay-off when done on such a scale. It is called economies of scale. Agricultural crops in itself are done on massive scales.

For example, let us take the individual solar PV as independent source. Each peak Watt power capacity costs anywhere from $5-$10 installed after rebates. If you total all the household to reach 400 MW, it would have cost $2B to $4B. Thus there is economy of scale in larger setup .

In California for example, super massive arrays of solar PV or dishes are planned to generate several gigawatts power capacity, and each of the project module would be anywhere from 300 to 600 MW capacity, and they cost roughly the same as the solar tower of the same capacity. While costing at par, they don't have the greenhouses to grow your crops. It is single purpose, for production of renewable energy. With the solar tower combined with greenhouse, there is a chance for faster payback. You produce both crops and energy.

After all, plants would normally waste more than 95% of the solar energy it gets, mostly in terms of evaporating the water (requires a lot of energy) and reradiation. With the solar tower, you are able to recover significant amount of what have been lost energy while you still have your crops.

The enclosed structure would allow for organic growing without the use of pesticides, and you get cleaner crops free of insect pests.

Done on a small scale, the solar tower wouldn't have enough wind velocity to power wind turbines, but nonetheless, the solar tower can be used to cool the houses in combination with passive geothermal setup.

[broli]

You are assuming no free energy device would be invented by now and the time this pays off. Don't depend on "economy" to much it has brought the mess the world is in today.

[JoeReal]

Economy and "economies of scale" are two different things. Don't be confused.

[wpage]

All relative

The question of scale in solar energy applied to the natural world...

In the relm of photosynthesis from a simple blade of grass vs the mighty sequoia tree. Same harness of light energy supporting life.

Which is superior life form?

[ANTIQUER]

Hi Joe;

Since this is approx. 3 times the height of the tallest building in the world and I doubt if the government of Namibia has 600M. Euros (or anywhere near it) I'll go with a hoax or practical joke.

Al