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Comment by knolan | Hacker News Reader

It’s a nice idea and I’m glad to see it investigated, however the efficiency of kinetic energy generation from a regular turbine is always going to be greater.

Oscillation from vortex shedding behind a cylinder depends on separation of slow moving air and the subsequent imbalance in lift on either side. You’re using some of the kinetic energy of the flow to induce the vortex shedding.

A regular turbine on the other hand uses very efficient airfoils where you can at attempt to maintain laminar flow and maximise energy extraction.

I see this technology as being great for energy harvesting on existing infrastructure. Put vibrational energy harvesters on pylons and poles in windy areas and you could power traffic lights, street lights etc.

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Regular turbine will be always be more efficient per square km of wind plant, but are you you sure that regular turbine will be always more efficient per dollar invested in construction?

Yeah reducing the costs of maintenance would be huge for this industry.

While it's true the vortex design has no moving parts and is thus inherently simpler, a regular old turbine is hardly a complicated machine. A bunch of fixed blades, some gearing, and an electric motor -- all of which are routine things that can be mass produced in huge quantities and have been for decades. Really the only serious difficulty with building out a modern turbine is the size of the blades and the transportation complexity of getting them to the site on existing road networks. And these Vortex things seem to be about the same size.

Yes but you can put more of them in the same space, total cost is likely going to be lower and you can put them into places where turbines can not go. If they manage to make it to market they could be huge.

Unfortunately not, it has fundamental issues, the largest of which is that these devices only scale linearly compared to HAWTs which scale at h^2. Putting in more of them won't over come the scaling losses, neither will the cost reductions; even with twice the number of them and with 50% reduction in cost, you're still loosing linearly at 30% to HAWTs h^2 gains.

https://cleantechnica.com/2015/05/21/bladeless-wind-turbine-...

Vortex shedding can be incredibly efficient for generating force. It's how bees and hummingbirds fly. The big advantage of this wind power plant is that it could have a much lower cut in speed, capturing energy even at lower wind speeds.

I think one should be really careful when translating fluid dynamics things from hummingbird sized objects to wind turbine sized objects.

Will this be safer for bird life?

The risk that wind turbines pose to birds is already very small. Wind farms kill 440 thousand birds per year. Meanwhile, building windows kill about 500 million, and cats another 500 million. A standard wind turbine kills 4.27 birds per year, so of course you shouldn't build a massive wind farm in an area with endangered birds.

Outside of that case, what if the whole US was powered by wind energy? That would mean 315333 wind turbines, causing 1.34 million bird deaths per year. That's still negligible compared to cats, windows, hunting or communication towers.

sources:

https://en.wikipedia.org/wiki/Environmental_impact_of_wind_p...

The US uses 473 GW on average, A standard wind turbine produces 1.5MW. 473000/1.5 = 315333. https://en.wikipedia.org/wiki/Energy_in_the_United_States#Co...

It’s not all about numbers. Wind turbines kill rare, and threatened species, such as birds of prey and bats. Cats and window accidents mostly kill very common species.

...which is why, as the parent states, they shouldn't be built in the habitats or flight paths of endangered species. Environmental impact studies are now a routine part of the wind farm development process, and have been for over a decade.

How many birds do you think a mountain top coal mine kills?

Why was this comment flag killed???

Modern wind turbines already are safer for bird life. The windmills that killed raptors were the small fast-moving ones, which are being replaced by more efficient, and gigantic, slow moving ones.

Do you have citation for this? I looked on Google and it's a jumble of conflicting reports.

My reason for doubting is that modern turbines turn slowly in rpm, but the blade tips are still moving extremely fast. Like, just barely sub-sonic fast. So I could well believe that might still be an issue especially for large birds.

We should try to make wind turbines safe for birds because it's the right thing to do, but we should focus our energy elsewhere if preserving bird life is a goal: https://www.motherjones.com/politics/2013/01/chart-cats-vs-t...

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