[Coral-List] OTEC around coral reefs

[Bill Allison]

The devil may be in the details and engineering incompetence.
Such a venture was attempted for A/C purposes by an American stationary
engineer at a private enterprise in the Maldives ~15 years ago. Given their
location the coldest water they could hope to access was 13C which didn't
seem cold enough, as indicated by Melbourne, especially given that a 3 km
long pipe, much of it running through warm water, would be required to
reach that water. The proposed discharge of the warmed water into the
lagoon reeftop shallows also seemed problematic for reasons Alina indicated.
How the water was to be distributed on-island was never described but it
seems likely to have been a challenging engineering problem.
In the event, several rather more mundane engineering incompetencies
scuppered the multi-million dollar exercise: (1) inappropriate pumps; (2)
even with appropriate pumps, too small a diameter pipe with inherent
turbulent flow issues meant adequate flow rate could not be achieved, and
(3) the anchor weights on the pipe slid down the pipe to the bottom of the
reef slope as the pipe was lowered so the shallow water portion was forced
to the surface when the tide was running. I suppose it could have been used
as a tourist attraction, but it was deemed a shipping hazard and had to be
removed.
Take home: Make sure those in charge are up to the job.
Cheers,
Bill

On Wed, Jun 17, 2020 at 8:35 AM Meesters, Erik via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Hi all,
> There are now plans for an OTEC facility on Bonaire.
>
> It basically means pumping up cold water from the deep to cool things and
> discharging warmer water (often shallower).
>
>   *   Here are some examples: https://nelha.hawaii.gov/
>   *   http://otecokinawa.com/en/OTEC/WaterUses.html
>
> I can think of a lot of doomsday scenarios, but I'm looking for reports,
> assessments, thoughts, advice.
> Does anyone have experiences with OTEC facilities in the neighbourhood of
> coral reefs?
> it's often presented as the goose with the golden eggs, and governments
> seem to fall for it easily, but apart from glossy sales talks, I can't find
> objective reports or EIAs.
> Thanks for your responses.
> Best wishes,
> Erik Meesters
> Wageningen Marine Research
>
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