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Power Earth

Could Marine Energy Be the Final Frontier for Renewable Power? (cnet.com) 175

CNET explores the potential of "marine energy," starting with "an ambitious endeavor nearing completion off the coast of Oregon, where 7 miles of conduit were laid under the floor of the Pacific Ocean using pioneering horizontal drilling techniques." Soon, thick cables will be run through that conduit to connect the mainland to PacWave, an offshore experimental testbed built to develop and demonstrate new technology that converts the power of waves into onshore electricity. Once fully operational (as soon as 2025), PacWave could generate up to 20 megawatts, enough to power a few thousand homes.

"I get really excited about wave energy because the resource is so large," Levi Kilcher, a senior scientist with the National Renewable Energy Laboratory, told me. Kilcher is a lead author on the 2021 National Renewable Energy Laboratory (NREL) report that compiled available data on marine energy sources in the US, including waves, tides and ocean currents. The team found that the total energy potential is equal to more than half (57%) of the electricity generated in the U.S. in a single year...

Waves are just one potential source of marine energy that scientists and officials are investigating. Andrea Copping, a senior researcher at the Pacific Northwest National Laboratory, says there's renewed interest in another form of marine energy: ocean thermal energy conversion, or OTEC, which involves bringing up colder water from deeper parts of the ocean. This chilly flow then goes through a heat exchange process with warmer surface water, similar to the way home heat pumps exchange hot and cold air. That process drives a turbine to generate electricity... A small OTEC plant has been functioning in Hawaii for years. Copping believes new commitments from the U.S. government hold promise for the future of the technology, which has also seen significant interest in Japan and other surrounding nations.

It's possible that concern over climate change could unlock new sources of funding for OTEC... There's also the added bonus that the cold water pipes can double as a form of air conditioning in the tropical locales where OTEC works best.

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Could Marine Energy Be the Final Frontier for Renewable Power?

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  • No, it's shoddy research.
  • by Luckyo ( 1726890 ) on Monday May 15, 2023 @02:54AM (#63521727)

    The answer is "no".

    We've been trying to figure out how to extract energy from waves in a meaningful, economic fashion longer than we had electric power. It just isn't meaningfully doable. Wear and tear is horrendous for power you're getting, and mechanics involved are really nasty as there's no reliable way to directly translate random wave motion into circular one, which is the most efficient way of power generation we know.

    The only "marine energy" that has any meaningful potential is attempting to harness some of the oceanic flows as we can actually generate a rotational motion there. Problem there however is relative size of any installation, remoteness from point of consumption and again, wear and tear. Salt water wrecks havoc on everything mechanical.

    About the only other option is some kind of massive mechanical engineering breakthrough, that would allow us to get reliable and efficient energy extraction from semi-random wave motion without extreme wear and tear. Attempt mentioned in the OP is silly, but it's a good demonstrator of a level of desperation trying to harness wave energy. Potential is indeed massive. It's just that we have no practical ways we know of to extract the energy and convert it into electricity. So even massively wasteful ones like one in the OP is getting attempted. Sometimes its worth throwing a kitchen sink at a problem because potential of accidentally hitting a bullseye a kilometer off if a shard coming out of it shattering upon landing just happens to fly really fast for some reason earns you a lottery win.

    • by Phillip2 ( 203612 ) on Monday May 15, 2023 @03:08AM (#63521737)

      However, there are grid connected exemplars of many of these pieces of technology. There are two tidal flow plants in Scotland (using different technology), wave generators with several different technologies (Scotland, New Zealand) both in the sea near shore and onshore.

      Indeed, salt water is corrosive, but marine technology is also very old and well developed. And because of offshore wind, we are starting to develop lots of infrastructure in the sea -- offshore wave could hook up to the grid connections of wind, even the anchorages.

      For my money, I think tidal is more likely to take off, because it's extreme predictability will offset the extra price.

      • by olau ( 314197 )

        The problem is not just corrosive salt water, but the forces involved, due to the density of water.

        The generator needs to be built cheaply, be big enough (or otherwise scalable) to make it worthwhile, and last for a long time, again compared to the forces involved. Even with a good design you need to built a lot of them to achieve economy of scale.

        Demonstration plants are fine, but if there's no feasible path from the demo to full-scale production of new plants, then they won't go anywhere.

        • by HiThere ( 15173 )

          I can see lots of "special case" scenarios were if it were well developed, it would be useful. Lots of islands could use something like this. But I don't expect it to ever be a major factor. We'll see.

        • The density of water is a problem but, also, of course the whole point. A water born turbine does not need 100m blades to make it viable.

          I agree that plants need to scale; but the demonstration plants being built now are well up the technological readiness scale. They are grid connected, semi-commercial offerings, coming in with a strike price greater than wind, but only by a couple of times (i.e. still less than nuclear). There is also another going in which is not grid tied, but connecting directly to gre

    • by olau ( 314197 )

      Here's one I know of with a funky concept that tries to work around these challenges: Wavepiston [wavepiston.dk]

    • || there's no reliable way to directly translate random wave motion into circular one, which is the most efficient way of power generation we know. Depends on the scale you are imagining. If we go to the molecular level, we may indeed find solutions, or have unrealized solutions already. Perhaps it is a floating blanket imbedded with piezoelectric crystals, or electromagnetic nodes small enough to extract energy at a very high saturation rate. Get at it, the solution is out there, or in your head already.
    • | there's no reliable way to directly translate random wave motion into circular one, which is the most efficient way of power generation we know. -- Depends on the scale you are imagining. If we go to the molecular level, we may indeed find solutions, or have unrealized solutions already. Perhaps it is a floating blanket imbedded with piezoelectric crystals, or electromagnetic nodes small enough to extract energy at a very high saturation rate. Get at it, the solution is out there, or in your head alread
  • Here we are trying to fight global warming, and they want to ADD more heat to the oceans? Has anybody tried to do an environmental impact study? Oh, look! Another domain we haven't dumped pollution into: we're already making it acidic, let's cook up a soup!

    Farking short-sighted greed.

    • When you move energy away, temperature will decrease. Energy from the waves is always converted to heat at some point, that's also why the temperature at Niagara Falls is higher at the bottom. When you convert some of that to electricity and move it on shore, then the water temperature will decrease (or increase less than naturally). It is not like solar panels in the desert, where the increased absorption of solar radiation (compared to the more reflective sand) more than offsets any of the electric energy
    • zero-sum game (Score:5, Interesting)

      by Petr Blazek ( 8018844 ) on Monday May 15, 2023 @05:49AM (#63521935)

      these solutions mean mostly redistribution of heat, not releasing stored energy (chemical, nuclear) that would otherwise not contribute to the energy balance.
      Even if so, the direct effect of "new" heat on the global thermal equilibrium is totally negligible.
      What causes problems are secondary effects (CO2 et al.)

    • by gweihir ( 88907 )

      Actually, this has been considered and is not a factor. CO2 and Methane have so massively more impact that this one here does not matter at all. And if you consider that this replaces CO2 generating Installations, the effect becomes positive. CO2 does a massively more damage than the heat that is generated when creating that CO2 by burning stuff. That is the whole reason we are in this mess. The actual heat from energy generation is negligible overall.

  • by louzer ( 1006689 ) on Monday May 15, 2023 @03:48AM (#63521831)
    The world consumes about 19 terawatts of electricity per hour, or 19,000 megawatts. This is equivalent to about 100 times the power of the Hoover Dam. The world's electricity consumption is growing rapidly, and is expected to reach 26 terawatts by 2030
    • by AmiMoJo ( 196126 ) on Monday May 15, 2023 @04:20AM (#63521867) Homepage Journal

      That's why it's so important that we push renewable technology and make sure it is available to developing nations. If they can build their infrastructure from the ground up to be suited to renewables, that will hugely limit their peak emissions. By demonstrating a high quality of life with renewable power, they will have confidence to adopt it.

      • That's why it's so important that we push renewable technology and make sure it is available to developing nations.

        I think what you meant is: That's why it's so important that we demonstrate renewable technology work at scale and make sure it is available to developing nations.

        Is there already a developped country which is powered mainly by renewables, and which emits less than 50g CO2eq/kWh (if yes, please quote your source)? Not that I know of, even though developed nations have way more money to throw at the problem than developing ones.

        In that case, pushing for renewables only (emphasis on the only) is pure hypocris

        • by AmiMoJo ( 196126 ) on Monday May 15, 2023 @05:20AM (#63521909) Homepage Journal

          Iceland. 73% tidal, 27% geothermal for electricity. Heating is 99% geothermal.

          Norway is also over 90% hydro for electricity, with the bulk of the rest being wind. Heating is more mixed, with a lot of waste burning and biofuel.

          Costa Rica is also almost entirely renewable for electricity generation.
          Source: https://www.grupoice.com/wps/w... [grupoice.com]

          Kenya is over 90% renewable.

          There are more, but I think the most interesting one is Germany. They aren't there yet but they have a legally backed target of 80% renewable energy by 2030, and are working towards that. They get a lot of hate for shutting down nuclear, but nuclear isn't an option for a lot of nations, especially developing ones. Germany is doing the hard work of converting a fairly dirty grid, and the experience and technology is already being exported.

          • by sonlas ( 10282912 ) on Monday May 15, 2023 @07:27AM (#63522031)

            They get a lot of hate for shutting down nuclear,

            No, they get a lot of hate for emitting a shitload of CO2, although they had the means to be amongst the best for the last 40 years but they chose not to. And they still emit a shitload of CO2, as you already know, especially per kWh generated. We'll see what the future holds for them, but we will probably be able to still say the same in 10 years. Which is proof that their communication strategy is working.

            Thanks for the examples though, although Iceland and Norway are kinda special in their own way, due to the nature of their landscape, and the low density of population that they have. Iceland is 345k inhabitants for instance, and they CO2 per capita is one of the worst due to the fact they have to import almost everything, and are using big 4-wheels to drive around the country. Very nice country if you have the chance to visit though, just not a good example in terms of what we need to do for the climate.

            Kenya is interesting, although the sources I found say: "Despite significant strides in renewable energy development, about a quarter of the Kenyan population still lacks access to electricity, necessitating policy changes to diversify the energy generation mix". Not sure it qualifies as a "working example".

            • Re: (Score:2, Insightful)

              by AmiMoJo ( 196126 )

              Germany has that legally binding target for 2030, and it does force politicians to act. They are well on their way to it and if they keep up the pace should get there. They have been steadily reducing their use of coal, for example, and gas.

              Every country is special in its own way. Every country has unique geography and geo politics. Norway exports a lot of oil, but has the chance to switch to exporting electricity. They have massive North Sea wind resources, for example. While the Middle Eastern oil produce

          • by electroniceric ( 468976 ) on Monday May 15, 2023 @08:08AM (#63522117)

            This is an interesting point.

            One thing that strikes me about the renewable energy conversation is that if any fraction of these new energy initiatives work, we will have a lot more energy available at a lower price. I say lower price because it seems the likelihood of raising the price of carbon-emitting energy sources is relatively low at this point, so new options will almost certainly have to be priced lower to be competitive. And since (non-baseload) solar and wind are already below the cost of fossil fuels for electricity generation, any new electrical generation will also be competing with that. Heating might be a different story, but it's still hard to see widespread carbon pricing happening in the short term.

            I can imagine in a decade or two we will be awash in cheap energy. I wonder if anyone has thought through the consequences of that.

            • by AmiMoJo ( 196126 )

              On the one hand it's likely that demand shaping and interconnects will stabilize the price of grid energy somewhat. On the other, if you have your own generation and/or storage, i.e. solar on your roof, with batteries or hot water storage, then for individual households energy could be basically "free". Of course there is a cost to buy the panels and maintain the system. Battery storage could be the car you were going to buy anyway.

              It will be interesting to see what happens with standing charges and grid co

          • by prisoner-of-enigma ( 535770 ) on Monday May 15, 2023 @08:55AM (#63522255) Homepage

            Iceland. 73% tidal, 27% geothermal for electricity. Heating is 99% geothermal.

            Norway is also over 90% hydro for electricity, with the bulk of the rest being wind. Heating is more mixed, with a lot of waste burning and biofuel.

            Costa Rica is also almost entirely renewable for electricity generation.

            Each of these countries is uniquely positioned to take advantage of local, natural renewables. Some of them -- like Iceland -- also benefit from extremely sparse population densities. This is not the case for the rest of the globe. The areas where this is feasible are extremely limited.

            • by AmiMoJo ( 196126 )

              So what is the excuse of other countries that also have excellent renewable resources but have not exploited them yet?

          • they've basically told the entire world "get off oil and nat gas, _now_". They've probably accelerated by shift by 20 years. It's 30% of their economy, and it's more or less going to disappear. Yeah, China & Africa are still developing so they'll keep buying, but like any commodity when demand drops so does price.
    • The world consumes about 19 terawatts of electricity per hour,

      "Terawatts per hour" is a not a unit of energy production ("watts" already includes "per unit time"). If you want people to listen to your comments, accurate terminology would help. (I agree that the fact that many internet sources use mixed units like "gigawatt-hours per year" confuses things.)

      In any case, Hoover dam is 2 GW, and 19TW/2GW = 10,000. World electrical consumption is ten thousand times the power of Hoover dam (not a hundred)

      https://powerauthority.org/abo... [powerauthority.org]

  • Wave-generators deliver power also when the sun doesn't shine, the wind doesn't blow, the nukes are shut down because of missing and too hot cooling waters....

    • by vyvepe ( 809573 )
      Waves as we know them are mostly generated by wind. So there can be periods of time when energy generated from waves is negligible. But waves travel a long distance so low wind area must be huge for waves to disappear at a given place. This happens more commonly in the equator area and it is called doldrums.
      • by gweihir ( 88907 )

        That is why you want tidal in the mix as well. Nobody is stopping the moon anytime soon.

    • by gweihir ( 88907 )

      ...the nukes are shut down because of missing and too hot cooling waters....

      Or because of massive safety issues, like in France currently. To be fair, France had to shut down river-cooled nukes in warmer summers as well.

  • So, if we harness all waves, tides, and ocean currents around the US, we can produce half the electricity needed. Electricity production is likely to go up by an order of magnitude, as heating, transport, and industrial processes switch. By then, harnessing all waves, tides, and ocean currents will cover less than 10% of the required power.

    That is not a large resource. That is a pathetically small one, and one which requires covering the ocean in energy harvesters.

    Wave power has been scamming investors for

    • So, if we harness all waves, tides, and ocean currents around the US, we can produce half the electricity needed.

      Nope. This is like mistaking "oil reserves" as "once we pull that much oil out it is all gone" rather than "This is the amount we can pull at $X per barrel, given new technology or a higher price, more would be available."

      Reading the actual report, they use the term "technically available". This means that, doing things like avoiding blocking harbors, shipping routes, lower power wave areas, and using existing technology(at existing efficiency rates) for large fields, avoiding harming the wildlife, and al

  • No.

    The article says wave power could be equivalent to 57% of current US electricity production. Meanwhile wind power is several times that and solar is hundreds of times that, and they occur inland, not just at the coasts.

    Further, wind turbines and solar panels are mature, mass-produced technologies that are already cheaper than fossil fuels and get cheaper every year. Wave and OTEC could move that way, but they're up against some pretty big barriers (1) a corrosive, difficult environment for installation,

    • And before you come at me about how wind and solar are intermittent and OTEC or nuclear are steady: I'm amazed at the technical pessimism around here when it comes to energy storage or syncing demand to supply in the grid.

      With a few batteries or simple tech solutions like better scheduling of water heaters and EV chargers or storing cooling energy as ice, we can use 95% of wind and solar power on the same day it is produced.

      And on days with more wind and sun than we need (most of them), we can make hydrogen

      • by gweihir ( 88907 )

        Indeed. In the end, any tech that is clean and can produce power at reasonably competitive rates is desirable to have in the mix. The more diverse power generation gets, the more reliable it is. Nuclear does not qualify due to excessive cost, high risk-cost, inflexibility and unreliability.

        The only "rational" reason for nukes is being able to make bomb-material. That was the original motivation (e.g. Windscale) and that has not changed. That is also the only reason why the extreme costs for this otherwise f

  • It works. It's pretty harmless as far as intruding on the ocean environment.

    They've got offshore wind here just off Martha's Vineyard island, and the most disruption it's caused so far is when they had to dig up a road to run the giant cables under it from the shore where they landed. https://www.vineyardwind.com/ [vineyardwind.com]

    They've only done test builds and power tests, but it's supposed to start supplying power to the grid shortly. Literally anything is better than continuing to pay Eversource their monopoly pr
  • I at first pictured a bunch of burly men sitting on a bench rowing a generator and not an oar.
  • Look, I know that wind energy is vast, and we're only taking a teeny bit of it.

    Wave energy is a HUGE amount of energy that we're only talking about scratching an infinitesimal portion for ourselves.

    70% of the planet is ocean; pulling up driblets of cold water isn't making a difference....

    BUT....

    There's a niggling voice in the back of my head thinking about the scene where Don and Betty go for a picnic, he crushes a beer can and whips it off into the forest.

    We used to think that a lot of the stuff we did did

    • > Don and Betty go for a picnic, he crushes a beer can and whips it off into the forest. ... and then she cleans up the rest by shaking everything off the picnic blanket onto the ground.

  • Remember, Geothermal energy is available from every point on the globe -- it's simply more difficult to reach if you're not near an active volcano (like in Iceland). This is yet another form of energy we could tap, should we ever decide to get serious about eliminating petroleum from our daily diet.

  • ... lots of equipment floating on the surface, tethered to stuff on the sea floor with cables. I can just imagine the whale entanglements.

  • "Could Marine Energy Be the Final Frontier for Renewable Power?"

    Well, let's see...

    > where 7 miles of conduit were laid under the floor of the Pacific Ocean

    Ok...

    > enough to power a few thousand homes.

    Morgan Freeman's voice: "...it was not"

  • Back in the 30's, this guy just used a pipe to move cold water up from the depths:

    https://argonautes.club/george... [argonautes.club]

    Okay, so it didn't work out very well. But it sure proved the concept.

    I faintly remember another experiment back in the 30's or 40's, one done on the really cheap and simple. I seem to recall a bunch of scrap iron (old radiators and such) cabled together and sunk into the depths right off the Cuban shoreline. The cable ran to another huge chunk of scrap iron submerged in a big asphalt-lined

  • If you think putting too much CO_2 into the atmosphere is bad, just wait til you see what happens when we invert the oceans' thermocline.

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