Technical advances that could make wind power viable everywhere | Hacker News Reader

Technical advances that could make wind power viable everywhere

arstechnica.com

One thing to bear in mind is that there are theoretical Limits to windmill efficiency: http://en.wikipedia.org/wiki/Betz's_law

In short, we can't extract more than about half of the available wind energy, no matter what the design.

This is because if all kinetic energy is extracted, the air would no longer be moving behind the windmill, so it would stop turning. Betz's law is the optimum compromise between extracting energy and sufficient airflow to keep the windmill rotating.

Wow! The concepts underlying Betz's Law are intuitive, though, still too clever for me!

I found the economic implications interesting. Given a Betz Limit of ~59% wind energy extraction, "utility-scale wind turbines" ...

  A) can only capture 80% of the peak (Betz Limit)
  B) achieve 25-60% of their potential output (constant wind) on an annual basis

Combining this with the NREL maps shared by animats below, you can make SWAG's for energy production in locations.

I'm concerned about all the math being per-area, which makes bigger windmills seem inevitable. But surely its per-dollar that determines commercialization potential. 1000 small windmills could be the better choice if they could be made cheaper per watt after all.

Wind energy economics favor: fewer blades (though the three bladed design has some mechanical properties that make them the default choice), larger swept area, horizontal axis turbine (even though you need to aim those at the wind nobody has been able to produce a very large VAT that survived for even a short amount of time), direct drive (because gearboxes are very much prone to failure).

1000 small windmills would not be commercially competitive with a single large machine, would not extract as much power from the same amount of wind and would not be as safe. Small machines have to make a lot more RPMs so are inherently higher maintenance (bearing wear), harder to operate when connected to the grid and so on.

I'd love it if that weren't the case (which is why I built my own 5 meter/16' machine) but ultimately wind power will be dominated by several MW behemoths.

Living near a number of wind farms:

- They are noisy in a very annoying way - Swoosh Swoosh Swoosh. I don't know about you, but clocks ticking drive me up the wall. Now I can add wind turbine blades swooshing do the same. It's not really a noise so much as a pressure wave.

- They strobe. Sometimes reflecting the sun. Sometimes the blade shadows fall over you. Blink, blink, blink, blink.

- They are efficient bird murdering machines.

I like the idea of wind turbines. Reality is not nice. Bring on solar!

Its true solar is easier to live with. But regarding the last - solar is efficient everything-under-them murdering machines. They sterilize the land, similar to strip-mining but without the poison. So not really eco-friendly, which is ironic.

There's still a lot of area available for solar power that doesn't involve getting rid of plants, though. Deserts, house and car roofs, for example.

Everybody says 'desert' as if it isn't the most delicate ecosystem on earth. yes, solar panels covering up desert destroys that ecosystem too. Living things there are totally dependent on the large amounts of sunlight.

As for houses and car roofs - that amounts to almost zero in the big scheme of things.

The moon!

If they weren't covering 100% of the land and some light still fell between them, wouldn't low light plants thrive under them? A little mini ecosystem of flowers and insects, like under the canopy of a forest?

Now that sounds like a coal power spokesperson, defending their total disruption of an ecosystem. Sure, some balance may be found under the solar panels, after everything that was there is killed and replaced by something else that finds its way in.

But I doubt that. I grew up in Iowa. Under the canopy of the cornfields, absolutely nothing lives. The almost total lack of sunlight leaves very little energy to support an ecosystem. Its like the surface of the moon. Not even insects.

Transparent solar panels are being developed by MIT startup[1]. It's still in pretty much experimental state (and thus expensive to make), but future looks bright.

1. http://ubiquitous.energy/

It was strange for me too that environmental concerns were not taken into account in this article. At least in some European countries, it's the limiting factor as new laws are being passed to regulate wind farm building near populated areas or bird breading places.

Njummy, breaded chicken.

My house is in the middle of a bird sanctuary and there are giant 3MW windmills within a stones throw of the nesting grounds. I'm sure they occasionally swat a bird but it's not exactly as if the ground is littered with corpses, definitely not worse than alongside any major highway. And with 100K+ birds nesting there you'd expect to see at least some significant evidence of that theory.

There are many more step forward the wind energy industry can still see. Not only incremental ones. Before moving to SF I was at Energie Etiche, an Italian startup that is bringing to the market an innovative wind assessment software. By cutting the preliminary wind assessment time from 18 to 3 months and the relative costs from $15k to $2k-$4k it's possible to open up the whole "Small Wind Market" (aka <100KW)

Check out "Wind Prospector", which has a zoomable map and a wind model for the entire United States.[1] It uses a climatic model and topography data to calculate wind power potential. Spend a few minutes with that and you can see where the wind industry can and can't grow. For the US, the big potential is offshore and in the area due north of the Texas panhandle. California has four good onshore wind sites, and all have big wind farms already.

[1] https://maps.nrel.gov/wind-prospector

Yes, this is one of the possible approach to the wind assessment challenge. Unfortunately it is not accurate below 250ft, the wind is not linear and this kind of model doesn't count well enough all the obstacles at the low altitudes. Therefore this model doesn't work for the <100KW turbines and when it comes to >100KW, the investment is so big that you still want an on-site-specific wind assessment. In conclusion this service is useful only for curiosity or for preliminary observations

Local variations can be huge so you are spot on that for any site that expects to produce power a local assessment is a must. Even so a chart like that helps to determine whether or not going for windpower makes sense at all and how much you can (on average) expect to get out of it indicating what your 'mix' of renewables should be to ensure year-round power, which is especially important for off-grid installations.

That's really neat! You can see the location of every windfarm and tier within the U.S. It even has info for HI and AK!

> A European company is also selling a blade that is shipped in segments and then bolted together at the site of use.

Why is this "European company" not named? European companies are bad, while GE is good?

I think that refers to Gamesa.

https://www.google.com/search?client=ubuntu&channel=fs&q=gam...

Thanks for the link.

By the way, what really irked me is that I notice more and more how EU companies are very often shunned by US based media, which we in the EU use ourselves as reference. This was really a blatant case.

US based media are highly tuned to what their readers want to read and just focuses on American names/companies that their readers know most about in addition to not caring about what companies are doing in EU.

Did I miss a segment of that article on energy storage?

One of the most difficult components of making wind energy practical on a large scale for any grid is it's lack of predictability. I suspect that things are somewhat more predictable at higher altitudes but not so much so that it mitigates the challenge of having a turbine that isn't necessarily going to be spinning when you need it.

There is a nice picture of a new 4MW Enercon model in http://www.enercon.de/p/downloads/WB_012015_GB.pdf Showing most of these advances.

Enercon is absolutely incredible in how they steadily ramp up their production capacity and improve the yield and size of their machines. They're engineering marvels.

Is there anything preventing us from fabricating rotor blades on-site at large wind farms?

Rotor blades are extremely high tech, fabricating them on-site is theoretically possible by using a mobile factory but that factory would be several times the size of the blades that it produces, would need specialist operators, very well controlled conditions for the curing phase of the blades and a testing facility to ensure the end product is safe to install.

Compared to that fabricating them centrally and trucking them to the site (usually at night using 4 rigs, one for the nacelle and 3 for the blades) is a no-brainer from an economics perspective.

If an extremely large wind-park would be funded and planned many years in advance you could possibly build a windmill factory near it at an advantageous location and keep running it after the park is completed to supply other localities nearby.

What about using an unmanned, hydrogen filled, dirigible?

Either conventionally powered, solar powered, or simply towed from the ground along roads?

I'm liking the towing idea. To deal with bridges have two cables, and some drones to carry the cable over the bridge and back to the towing truck.

Wind farms are usually built in windy areas. Dirigibles are less controllable in windy conditions.

I can see how 3d printing could really help wind power. Printing rotor blades, and maybe even towers onsite could have drastic savings. The same type of powered platform that 'builds' cranes could be affixed to the tower with 3d printing capabilities. At the end, after it has climbed up the tower it build and printed the rotors, a crane could take it down, and install the mechanical components.

The forces on rotor blades are not in any way friendly or easily assessed, 3D printing 35 to 70 meter long structures with very well defined properties and extremely high tensile strength as well as resilience against fatigue is currently (and for the foreseeable future) not an option.

Windmill blades are limited in size by current materials science and requires a very large amount of high tech composites such as carbon fibre, resins and so on.

Towers are high grade welded steel, foundations are huge compared to the bit of the tower that pokes out above ground and none of all of that is currently made from a material that can be 3D printed.

3D printing is not magic.

Reply on news.ycombinator.com