Someone will probably mention birds pinned helplessly to the giant sail. I bet maintenance on the sail would be costly. Some sail boats use kevlar sails and cleaning them is a difficult and time consuming job. Imagine the time and cost to properly clean a 17,000 square foot kevlar sail. Once dirt starts to accumulate on the sail and get into the fabric it will begin to hold moisture that will add to the weight of the sail. The grit will also act as an abrasive and start to degrade the sail material. Salt and grit on a large sail can add almost 10 pounds of weight.

While kevlar is light, strong, and has a low stretch; it has poor UV resistance. The Sun's UV rays weaken kevlar over time. Kevlar also suffers from a rapid loss of strength due to flexing.

Vectran is better than kevlar and is naturally gold in color. It is very durable but is more expensive.

Taffeta would add film on film for abrasion, uv, and flex fatigue protection, but this adds weight to the sail.

Pehaps they could try a carbon or cuben fiber sail, although the cost would be much higher. 50~70% lighter and 4 times more durable than kevlar. It can flex without a loss of strength, has good UV resistance, and doesn't soak up water.

It would also be interesting to see if zinc oxide nanowires could be incorporated into the sail similar to the experiments with electricity producing clothing at Georgia Tech. 80 miliwatts per square meter is the potential.

Major problem with architects proposal.
Has very large area ratio and very poor turbine duct entry.
Area ratio greater than 2 / (porosity less than 50%) means any excess collection area wasted. See Energy Storing Wind Dams on www.greenzephyr.co.nz. Link to UK Hydropower magazine article recommended for best quick overview of technology.

I question the decision to use a wind turbine vice a wind compressor. The use of a wind compressor would reduce the capital costs associated with turbine generators, the gearbox, and variable speed electric motors. Furthermore, any energy fed into the grid using a wind generator is going to be subject to a bell curve of pricing depending on the demand.

In contrast, using a system such as CAES (Compressed Air Energy Storage), the wind dam would convert the kinetic energy of the wind into compressed air and store it in a nearby geological feature such as a limestone cavern until it could be sold back to the grid during peak demand. This method would improve profitability for the dam because it would provide reliable power at peak demand price.

There was also mention of using a conical sail to feed three turbines. A conical sail will require a larger skeletal support structure either in the form of sequentially suspended metal rings or a framework around the cone shaped sail. If they decide on conical then why not just build a metal cone? A metallic cone could include stators to better funnel and align the wind into the rotor. Several effective surface coatings are available that would help reduce drag inside the cone.

can anyone help tell me how this actually works in simpler langauge??

thanks