Each will cover 37.5 km2 area and generate 400 MW of electricity with 25 km2 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




GREENTOWER TECHNOLOGY AND COST

1. WORKING MECHANISM

Visible radiation from the sun and (overcast) sky heats the air inside the glass covered collector, the buoyancy of which causes an up-draught inside the centrally situated tall chimney flue driving turbine(s) with integrated generator(s) at the chimney foot. Present solar to power efficiency is 4%, theoretical (Carnot) limit = 25%, practical limit = development potential = 14%.

Vegetation inside the greenhouse increases power production according to Stellenbosch University, continuously researching the GT since 1998. The outer 2/3 of the collector’s area is used as a greenhouse and for air heating at the same time. Evaporated water is re-condensed.

2. SPECIFICATIONS

● The concept of the GreenTower® (GT) follows Prof. Schlaich’s Updraft Tower (Solar Chimney), but combines power station + greenhouse (high profits), recent international research results and unique experience in cooling tower design/building by Krätzig & Partner + related German experts.

● Flue height = 1 500m; flue-Æ:180 - 280m; collector-Æ: 6.9km; collector-roof height: 10–30m

● Power rating: 400Mwel (pure solar, emission-free); 32 turbines at flue perimeter with integrated linear generators; plant load factor ³ 89%; availability = 97%

● 6 day full power quick-response thermal energy store + seasonal store Þ power at any time

● Collector area = 37.5km², dry area = 12.5km²; outer ring = greenhouse area = 25km²

● Greenhouse: Drip irrigation + humus soil (12% £ humus £ 25%); high yield-low cost organic agriculture (microbial nitrogen fertilization); composted plant matter buried in soil as humus

● CO2 sequestration per GT + related irrigation schemes » 2 000MWel of coal-fired power emissions

● Design life-span = 160 years, depreciation period ³ 80 years; construct. period = 3 to 4 years

● Capital cost: Dry GT: €475m; greenhouse implements: €90m; glass factory: €35m


for more info:
http://www.greentower.net/exec.php

The ultimate greenhouse yet. This is extraordinary and 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!


Here's how the basic tower operates:
http://en.wikipedia.org/wiki/Solar_updraft_tower

Here's the news that Namibia government approved building such green tower together with greenhouse area:
http://www.engineeringnews.co.za/article/solar-tower-sheds-light-on-little-used-technology-2008-07-25

And here's the short Executive summary of the project:
http://www.greentower.net/exec.php