A new design ship in the Philippines is partly powered by wave energy

Post by callamdelaney » Thu, Aug 06, 2020, 2:18 PM UTC

sephamorr wrote: post #42

mehrdadn wrote: post #25

Earlier quoted context omitted.

> The digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page view. Holy cow, that is a lot . 1-3 grams of CO2 per single load of a page? Makes me feel guilty about even clicking the article.

I'm having a very hard time rationalizing these numbers. Something has to have some very poor assumptions: Let's assume each page load is ~1mbit, and it's being served from 1000km away. 1mbit may be low, but most of it will presumably be content delivered by a CDN which is far closer than 1000km. The reference design (which I work on) for 400G DWDM systems are ~100W for 2 transceivers + EDFA + switches, for a standar…

Post by donaltroddyn » Thu, Aug 06, 2020, 2:31 PM UTC

efavdb wrote: post #80

Zeebrommer wrote: post #63

Earlier quoted context omitted.

This is exactly the kind of order-of-magnitude estimation that I was looking for in the article. Where did you get the wave energy numbers?

Here's a quick estimate: The potential energy of the wave will go like mass x gravitational acceleration x height. If the depth (front to back) of the wave is about 1 meter and the height is also about 1 M, then per meter of wave we get M g h g = 10 m / s^2; M = 1 g / cm^3 = 10^6 g / m^3 = 10^3 kg / m^3; H = 1 m MGH ~ 10^4 Joules per meter If a wave comes every 10 seconds —> 10^3 joules / sec, not far from what this…

Post by pjc50 » Thu, Aug 06, 2020, 2:36 PM UTC

duxup wrote: post #82

pjc50 wrote: post #37

Earlier quoted context omitted.

What sort of wave foil do you mean? It's not clear from this article how the trimaran works, but you can see in the photos that there is a gap at the top of the outboard hulls. So I suspect it's the relative motion between the outboard hulls and the inboard one which is converted to hydraulic power - makes sense, it will be a short movement with a huge force behind it. That is then fed to a generator, electrical stor…

Most seem to involve a wing or fin extending out from the hull in some way. That seems like it would introduce drag and greatly limit speed.

Post by irishjohnnie » Thu, Aug 06, 2020, 2:43 PM UTC

just-ok wrote: post #5

It’s honestly a shame that we didn’t keep pursuing sail technology. It’s great that we’re finally getting somewhere environmentally-friendly with ship tech nowadays as in the OP, but if we’d put the same amount of effort to innovate and advance sails like we did steam, I imagine we’d have pretty amazing (and completely green) methods of transport for all but the heaviest cargo loads (and even then, just split the loa…

Post by jasonwatkinspdx » Thu, Aug 06, 2020, 4:31 PM UTC

duxup wrote: post #82

pjc50 wrote: post #37

Earlier quoted context omitted.

What sort of wave foil do you mean? It's not clear from this article how the trimaran works, but you can see in the photos that there is a gap at the top of the outboard hulls. So I suspect it's the relative motion between the outboard hulls and the inboard one which is converted to hydraulic power - makes sense, it will be a short movement with a huge force behind it. That is then fed to a generator, electrical stor…

Most seem to involve a wing or fin extending out from the hull in some way. That seems like it would introduce drag and greatly limit speed.