6 ms·

> Something I haven't seen discussed anywhere, but to me is almost obvious - these various wave generators we see in discussion for off-shore use. Is there a wa

by DeRock 3y ago

> Something I haven't seen discussed anywhere, but to me is almost obvious - these various wave generators we see in discussion for off-shore use. Is there a way that technology can be used in the Columbia, Snake, etc without the need for a dam? There are some companies doing small scale hydro, by taking advantage of the natural flow of a river, without the use of any dam/head. Eg. see https://emrgy.com https://emrgy.com, and a volts podcast with the founder/CEO: https://www.volts.wtf/p/how-to-make-small-hydro-more-like#details https://www.volts.wtf/p/how-to-make-small-hydro-more-like#de...

poulsbohemian 3y ago
Yeah, my gut tells me when we get to a point where we have to either rebuild or remove a lot of these dams, we'll pursue technology like this as a happy path. Or at least that should be part of the options.
bozhark 3y ago
What’s the output of such device?
- TkTech 3y ago
  10kW to 40kW according to their spec sheet[1], so seems irrelevant as an alternative. A single one of the older dams getting replaced, the Iron Gate Dam, has a capacity of 18MW. One powers a single small farm, the other powers entire towns, heavy industry, foundries... And to be clear, these are small, old, dams. Modern dams and turbines produce far, far more. [1]: https://emrgy.com/wp-content/uploads/2021/06/Emrgy-Specifications.pdf https://emrgy.com/wp-content/uploads/2021/06/Emrgy-Specifica...
  - timerol 3y ago
    These turbines are meant to be used in a fleet, along a river. They take about 16 feet across per pair, so call it 20 across the normal flow of the river. They also do not block the flow, so more can be installed a little downstream, depending on the pitch of the riverbed. Assuming 5 groups per mile, 10 miles of flow of the Klamath River will give you the capacity to install 1000 of these, for a total capacity of 10 MW to 40 MW. Saying that these are too small is like saying that solar panels are too small. The module size has nothing to do with the total generation - they're built to be manufactured and placed in bulk. Source: I listened to the referenced podcast episode when I came out, and just looked at the spec sheet to refresh my memory.
    - AlbertCory 3y ago
      The rosy scenario, then, is lots of these little turbines? Won't there be separate NIMBY lawsuits about every single one of these, claims that they're unstudied and cause ecological damage, ruin the natural enjoyment of the river, etc. etc.?
      - justsomehnguy 3y ago
        In the rivers with minimal debris, with long enough stretches to place them all, with enough infra (read: cabling) to supply\gather electricity from them all to the one/two/three substation... All these while providing an efficient way to grind all the fishes.
        Arrath 3y ago
        And canoe or kayak enjoyers.
    - TkTech 3y ago
      These absolutely cannot be used in these kinds of rivers. Even their own promos only show irrigation channels. These things will chop salmon like sushi and running miles of infrastructure for them up and down a river is fantasy. Solar is far more practical and far more dense then these things to replace a hydro dam.
WJW 3y ago
> these various wave generators we see in discussion for off-shore use When it comes to wave power, "in discussion" is the operative word. Modern pelton wheels are 95%+ effective in converting kinetic energy into mechanical energy and have been in operation for decades. They are super well understood and optimized and are deployed at scales of dozens of megawatts per unit. Total installed capacity is probably into the hundreds of gigawatts. AFAIK, no wave power project is above 10 MW as of now and the total installed base is still tiny despite decades of research. Look at https://en.wikipedia.org/wiki/List_of_wave_power_stations https://en.wikipedia.org/wiki/List_of_wave_power_stations for example. It is a combination of the ocean being a super unfriendly environment for technology in combination with all of the wave energy extraction technologies being extremely inefficient.
seanmcdirmid 3y ago
Small scale hydro is pretty old. 15-20 years ago I stayed in a small inn/hotel in China in a national park on a huge mountain that got its power via a water wheel on a stream fed by melting glaciers. It was fragile, so occasionally it get pushed off, causing power to go out while the hotel staff repositioned it.
rgmerk 3y ago
No way you’re going to make as much electricity as with conventional hydro. Furthermore, you lose the ability to dispatch more or less electricity depending on demand, which is increasingly important in grids with a lot of wind and solar. It may well be that the environmental costs of many dams aren’t worth it - and lots of dams produce very little or no hydroelectricity. But run of river hydro is not an easy substitute for those hydro plants that do produce significant energy.

by DeRock 3y ago

poulsbohemian 3y ago

Yeah, my gut tells me when we get to a point where we have to either rebuild or remove a lot of these dams, we'll pursue technology like this as a happy path. Or at least that should be part of the options.

bozhark 3y ago

What’s the output of such device?

TkTech 3y ago
10kW to 40kW according to their spec sheet[1], so seems irrelevant as an alternative. A single one of the older dams getting replaced, the Iron Gate Dam, has a capacity of 18MW. One powers a single small farm, the other powers entire towns, heavy industry, foundries... And to be clear, these are small, old, dams. Modern dams and turbines produce far, far more. [1]: https://emrgy.com/wp-content/uploads/2021/06/Emrgy-Specifications.pdf https://emrgy.com/wp-content/uploads/2021/06/Emrgy-Specifica...
- timerol 3y ago
  These turbines are meant to be used in a fleet, along a river. They take about 16 feet across per pair, so call it 20 across the normal flow of the river. They also do not block the flow, so more can be installed a little downstream, depending on the pitch of the riverbed. Assuming 5 groups per mile, 10 miles of flow of the Klamath River will give you the capacity to install 1000 of these, for a total capacity of 10 MW to 40 MW. Saying that these are too small is like saying that solar panels are too small. The module size has nothing to do with the total generation - they're built to be manufactured and placed in bulk. Source: I listened to the referenced podcast episode when I came out, and just looked at the spec sheet to refresh my memory.
  - AlbertCory 3y ago
    The rosy scenario, then, is lots of these little turbines? Won't there be separate NIMBY lawsuits about every single one of these, claims that they're unstudied and cause ecological damage, ruin the natural enjoyment of the river, etc. etc.?
    - justsomehnguy 3y ago
      In the rivers with minimal debris, with long enough stretches to place them all, with enough infra (read: cabling) to supply\gather electricity from them all to the one/two/three substation... All these while providing an efficient way to grind all the fishes.
      - Arrath 3y ago
        And canoe or kayak enjoyers.
  - TkTech 3y ago
    These absolutely cannot be used in these kinds of rivers. Even their own promos only show irrigation channels. These things will chop salmon like sushi and running miles of infrastructure for them up and down a river is fantasy. Solar is far more practical and far more dense then these things to replace a hydro dam.

WJW 3y ago

> these various wave generators we see in discussion for off-shore use When it comes to wave power, "in discussion" is the operative word. Modern pelton wheels are 95%+ effective in converting kinetic energy into mechanical energy and have been in operation for decades. They are super well understood and optimized and are deployed at scales of dozens of megawatts per unit. Total installed capacity is probably into the hundreds of gigawatts. AFAIK, no wave power project is above 10 MW as of now and the total installed base is still tiny despite decades of research. Look at https://en.wikipedia.org/wiki/List_of_wave_power_stations https://en.wikipedia.org/wiki/List_of_wave_power_stations for example. It is a combination of the ocean being a super unfriendly environment for technology in combination with all of the wave energy extraction technologies being extremely inefficient.

seanmcdirmid 3y ago

Small scale hydro is pretty old. 15-20 years ago I stayed in a small inn/hotel in China in a national park on a huge mountain that got its power via a water wheel on a stream fed by melting glaciers. It was fragile, so occasionally it get pushed off, causing power to go out while the hotel staff repositioned it.

rgmerk 3y ago

No way you’re going to make as much electricity as with conventional hydro. Furthermore, you lose the ability to dispatch more or less electricity depending on demand, which is increasingly important in grids with a lot of wind and solar. It may well be that the environmental costs of many dams aren’t worth it - and lots of dams produce very little or no hydroelectricity. But run of river hydro is not an easy substitute for those hydro plants that do produce significant energy.