[ExI] How to tame hurricanes

[BillK]

On Thu, Dec 12, 2013 at 12:03 AM, Anders Sandberg  wrote:
<snip>
> Similarly the hurricane-stopping power of windfarms seem implausible. A
> hurricane is a massive heat engine involving the coordinated movement of
> millions of cubic kilometres of air: a low-altitude line of higher drag does
> not seem to be able to efficiently dissipate that much energy (how efficient
> are islands in protecting the coast?) Surely they can act as local help just
> like mangrove swamps, but a 50% decrease? Let's see, 50 m/s winds carry 1250
> W/m^2. So you need to dissipate 625 W/m^2. If we take a 50 km stretch of
> coast and try to block winds up to 100 m, I get 3.125 GW. A typical turbine
> in the London Array is 3.6 MW, so we need 868 of them. Spaced along 50 km
> that is one every 58 meter. Doesn't sound totally absurd (unless I
> calculated wrong somewhere). I get a rough cost of £4.6 billion ($7.5
> billion).
>
> If the above is right, then I do get worried about the effects of increasing
> drag on the global circulation system.
>
>

His simulation used 70,000 turbines. A bit more than 868.

Quote:
Jacobson's Katrina simulations assumed arrays of 70,000 turbines  —
300 gigawatts of installed power  — had been built 100 kilometers
offshore southeast of New Orleans and were designed to withstand winds
of up to 50 meters per second, just above the strength of a Category 3
hurricane, or roughly 111 mph.

The simulations showed that the turbines would create a net energy
reduction in the atmosphere, slashing wind speeds as energy was sapped
from the storm and dramatically reducing storm surge, which is caused
by high winds pushing water inland as a hurricane barrels toward the
coast.

Wind speeds would have been reduced enough to allow the wind turbines
to survive the storm themselves, with winds never reaching 50 meters
per second, above which the turbines could topple.
--------------

So he is thinking big indeed. And reinforcing his turbines.
He must be installing them in blocks, rather than a single line.

BillK