[HN Gopher] A new method boosts wind farms' energy output, witho...
___________________________________________________________________
A new method boosts wind farms' energy output, without new
equipment
Author : rntn
Score : 101 points
Date : 2022-08-12 13:05 UTC (9 hours ago)
(HTM) web link (news.mit.edu)
(TXT) w3m dump (news.mit.edu)
| linhvn wrote:
| Video illustration: https://www.youtube.com/watch?v=UP2yJqGQ2FU
| jacquesm wrote:
| Interesting development, but quite a few of these concerns are
| normally dealt with during wind park development and siting,
| taking care of the 'wake effect' in the prevailing wind with all
| machines operating is pretty much standard. The upside of this -
| if I understand it correctly - is that it will try to find
| another optimum when the wind is _not_ from the 'ideal'
| direction that the park was originally designed for. So it will
| depend very much on how variable the winds are in a particular
| locality whether this will give an advantage.
|
| I'm curious how it will play out in practice when they start
| using it on large offshore installations for instance.
| adrianN wrote:
| Using global control instead of local control seems like such an
| obvious improvement that I wonder why it hasn't been used
| earlier. I wonder whether the real difficulty lies in getting the
| simulations accurate enough to make useful predictions.
| asojfdowgh wrote:
| considering it amounts to 1.2% over a period, I wouldn't say
| "obvious improvement"
|
| local maximizing presumably already deals with the effects from
| upstream turbines, global (also presumably) only adds
| consideration for downstream turbines
| rocqua wrote:
| I suspect actually interfacing with the windmills is the hard
| part. Especially if you want to support many different types of
| devices.
|
| Local control, and no need for a global coordinator, might be
| so much simpler as to be worth losing some efficiency / not
| going into integration hell.
| maxerickson wrote:
| A typical wind farm will have 1 or 2 types of turbine.
| bluGill wrote:
| All the wind turbines in any given windfarm come from the
| same manufacture, and they all have monitoring and control
| from the utility's main offices in whatever city (at the very
| least they have enough control to prevent damage when the
| weather gets bad, I don't know what else they can do). As
| such all that is needed is a software update from the
| manufacture to give the central office more control.
|
| The utility might own wind turbines from different
| manufactures, but they are not in the same wind farm. I
| suppose there might be places where two wind farms border
| each other that you want different devices, but for the most
| part you can optimize each wind farm individually with no
| need to worry about manufactures.
| s1artibartfast wrote:
| I don't know that any of that is true.
|
| Farms can have different makes and models. I also think
| that there is a lot of on board control.
| bluGill wrote:
| Sure they can, but the reality how wind farms are built
| is they won't buy more than one make on any given farm.
| They place an order from some factory to deliver, getting
| a into the factory order stream is a large part of the
| process. Of course it does take a couple years and so
| there is plenty of opportunity for the factory to change
| internals in the middle, but the manufacturer is locked
| in before the first turbine goes up.
|
| Shipping is also rather expensive, so your are probably
| going with the nearest factory for everything. (each
| blade needs a semi with an oversize load permit, and
| "chase cars" both in front and behind with the right
| lights and signs)
|
| Of course if a turbine fails in 5 years (I don't know
| what the warranty is, so I'm going to use 5 years) they
| might replace it with one from someone else, but that
| isn't common.
|
| I don't know how much is onboard controls. However
| someone is feeding the weather instructions in, and when
| demand is low someone is telling a few to shut down. They
| also do remote monitoring for issues that maintenance
| needs to fix. That connection just needs an upgrade,
| along with some new software for the onboard controls and
| it can be done offboard. (this may not be easy, but
| compared to a turbine it is cheap)
| s1artibartfast wrote:
| Im guessing you are thinking of very different farms than
| I am.
|
| At the extreme, I am familiar with farms that have been
| expanded over 25 years and have a huge variety of builds.
|
| I am also aware of a number of farms that have at least 2
| different sized turbines.
| bluGill wrote:
| I count an expansion as just putting up a new wind farm
| next to a previous one, which happens often. At least in
| my experience the expansions often get a different model
| (visually different), but I count that as a new wind
| farm.
|
| I'm reasonably sure that all wind turbines in my area
| come from Siemans. (they have a factory in my state, any
| other make would be shipped in from a considerable
| distance)
| s1artibartfast wrote:
| If the turbines are close enough to impact the air flow
| to the other ones then they are effectively the same for
| the purposes of the cfd model in the parent post
| convFixb wrote:
| It has been done earlier; multiple times, by every serious
| manufacturer. :-]
|
| The real difficulty lies in:
|
| 1) Noise in the on-turbine wind speed and direction
| measurements and/or robustly (see point #2) operating LIDAR or
| met masts in front of the farm to try to avoid said measurement
| noise.
|
| 2) Actually arriving at a robust, operational in real-world
| conditions, fully closed-loop control system. A commercial wind
| farm has to operate 24/7 for 25 years without a bunch of
| engineers and scientists babysitting it, which is what is
| likely to end up happening if the cool control system relies on
| offline simulation results, topographical data, and/or human-
| supervised calibration & tuning.
|
| It's not all doom and gloom: Ongoing improvements in sensor
| price/quality will probably make these kind of global control
| systems more and more practically feasible in the future.
| 7952 wrote:
| Having off-site control of configuration and sensor
| information seems desirable and obtainable regardless. And
| once that is in place it is just a commercial decision. If
| spending x on cloud modelling delivers a multiple of x then
| its a simple decision.
| linhvn wrote:
| As the old say, the devil lies in details. Writing a global
| control is no means an easy task, as
|
| 1. You need to recognize the opportunities exist in the first
| place.
|
| 2. You need a global controller that can aggregate and optimize
| for a global solution (and the global solution might not
| necessarily simply to maximize the aggregate throughput, but
| there might be other factors into account), which may involve
| some algorithmic design (in some cases, you need to design new
| algorithms).
|
| 3. You need to justify that global controller gives you a
| superior solution compared to locally greedy solution. As in
| this article, a global solution gives you about 3% improvement
| compared to the local controller, and the local controller
| algorithm is substantially easier to write.
|
| Background: in my previous job at Meta, I wrote such a global
| control algorithm for controlling the rate of data going in and
| out each data center. It involved some really interesting
| algorithmic design.
| mlyle wrote:
| I think the real thing that's difficult is-- every
| installation is different, in the geometry of the turbines,
| turbine sizes, terrain shape, etc.
|
| Even if you have a perfect implementation of this, and you
| don't need to deploy new networks, etc, and you put in a lot
| of NRE to make this easy deploy... how much engineering
| effort is still needed to start squeezing 1-2% out of a wind
| farm?
| a_shovel wrote:
| It's a 1.2% overall improvement. That's the kind of number
| where it's worth doing in general, and worth using if it's been
| developed, but not nearly worth the development effort and
| headache for a wind farm operator trying to invent it on their
| own.
| jordz wrote:
| Cool. We have worked with a customer on this exact thing and
| deployed an edge and cloud controller that orchestrates control
| changes based on the all the turbines. Such a great project!
| mhb wrote:
| It's very hard to believe that this wasn't already standard.
| Silverback_VII wrote:
| For common sense nowadays you need at least 10 scientists and
| one big expensive simulation.
| ben_w wrote:
| You are severely overestimating "common sense". Joe and Jane
| Average (and by extension various stages of planning
| permission in certain locations) are still saying "but what
| about when theirs no wind!?!? lol" as if transmission lines
| don't exist.
| deelowe wrote:
| Joe and Jane Average are not designing windmill farms.
| There are clearly some very very smart people working on
| these systems.
| ansible wrote:
| Eh, not it is not hard to believe.
|
| The research was definitely worth pursing. A 1.2% overall
| efficiency gain is _not nothing_ , and is indeed significant
| enough that I think people will want to implement it.
|
| On the other hand, without doing some extensive research, it
| wasn't clear what the magnitude of the improvement actually
| was.
| deelowe wrote:
| This makes me wonder if it could be optimized further if
| mechanical design changes are explored. It's common practice in
| aerospace to minimize dirty air in certain cases. I wonder if
| there are opportunities where different turbine designs could be
| deployed depending on the windmill density.
| lizardactivist wrote:
| Why are wind turbines constructed like reverse propellers?
|
| Would they not be more efficient if they were shaped like an
| actual turbine with a deep spiraling blade, placed inside a
| cylindrical or conical encasing?
| jackmott42 wrote:
| I believe that if you consider the money it takes to add the
| conical casing, and instead just make a bigger tri-blade
| without a casing with that same money, you come out ahead.
| mynegation wrote:
| Not an expert, but that rings true. Probably environmental
| impact of a huge volume of air sucked into the cone and fed
| into a high-speed grinder should be factored in as well.
| deelowe wrote:
| It's not that. It's because they are optimized for low
| pressure differentials.
| s1artibartfast wrote:
| I'm sure both are true. It doesn't make physical sense or
| economic sense. Encasing the entire turbine with a shroud
| the diameter of the blades would be astronomically
| expensive.
|
| However, there is no rule in physics that you can't 10x the
| windspeed with a focused inlet.
|
| Natural mountain ranges around some farms have a similar
| effect to improve power output, but we would never consider
| building a natural mountain to improve turbine efficiency
| 5d8767c68926 wrote:
| > but we would never consider building a natural mountain
| to improve turbine efficiency
|
| Maybe we could? Mining operations already produce huge
| volume of material from tailings and overburden. Not an
| outrageous idea to be more strategic in how and where
| that material is placed. Could create some artificial
| ranges with better wind properties.
| elil17 wrote:
| This is a really good question. The reason regular turbines and
| wind turbines are designed differently is because regular
| turbines have a small volume of fluid experiencing a large
| change in pressure while wind turbines have a large volume of
| fluid experiencing a small change in pressure. You see the
| exact same thing in fans - big ceiling fans look like wind
| turbines and air compressors look a lot like regular turbines.
|
| I'm sure the cost of a casing plays into it, but its primarily
| about the energy efficiency of different blade shapes in
| different hydraulic conditions.
| Someone wrote:
| And if it were more efficient, there's the the challenge of
| rotating the casing when the wind direction changes.
| elil17 wrote:
| I mean the whole point of the casing as I understand it is
| to contain a flow at above ambient pressure - not something
| that even makes sense for wind. You could have different
| (more turbine-like) blade geometry without a casing.
| pjc50 wrote:
| There's a bunch of maths around Betz' law that dictates how the
| efficiency works, but it turns out that the theoretically
| optimal structure is a _single_ blade: http://www.wind-
| works.org/cms/index.php?id=543
|
| For mechanical engineering reasons, mostly to do with evening
| out the load at the point of blade attachment, the industry has
| mostly converged on three.
|
| This is also linked to tip speed ratio:
| http://www.reuk.co.uk/wordpress/wind/wind-turbine-tip-speed-...
| ; the tip speed is usually several times faster than the wind
| speed.
|
| Remember that the blades are aerofoils, effectively wings. They
| don't need to touch all the air in their swept area, their
| effect is given by redirecting the flow of the whole stream of
| air.
|
| Casings are only useful for small turbines operating at high
| pressures, where the energy lost to spilling over the tip of
| the blade would be high.
| DIARRHEA_xd wrote:
| > but it turns out that the theoretically optimal structure
| is a single blade
|
| In Betz's own derivation, the ideal rotor is an "actuator
| disk", having an _infinite_ number of blades, which have no
| drag.
| jacquesm wrote:
| Single bladers have - as do twin bladed machines horrific
| tower thump.
| jjk166 wrote:
| For the same reason propellers aren't shaped like compressor
| blades inside a cylindrical encasing. The cylindrical encasing
| dramatically reduces air flow, but is necessary for large
| pressure changes. For a brayton cycle heat engine, like a jet
| engine, you need to maximize pressure gradient for optimal
| efficiency, but if you're not burning fuel then you want to
| minimize pressure gradient and maximize mass flow rate.
| ansible wrote:
| You've already received some good responses (particularly from
| /u/pjc50), but one particular point may not be real clear.
|
| Generally speaking, the power a wind turbine can generated is
| proportional to the entire swept area. So, other things being
| equal, it is better to go for longer blades to increase the
| area, rather than trying to "capture all the wind" in a smaller
| cross-sectional area.
|
| So the most efficient use of your wind turbine's mass (which is
| proportional to cost) is to make it as big as feasible.
| timbit42 wrote:
| The Halcium Power Pod uses a casing to increase power
| generation by 40%: https://www.halcium.com/
| rr888 wrote:
| > Virtually all wind turbines, which produce more than 5 percent
| of the world's electricity, are controlled as if they were
| individual, free-standing units.
|
| I refuse to believe this, every wind engineer would know one
| windmill affects the next.
|
| Its not as clear as the picture either where they are lined up.
| In most locations wind changes direction so for some flows
| they'll interact different to others.
| calt wrote:
| Wind engineers know this, but the software control work is non
| trivial and, apparently, simply hasn't been done.
|
| A few years ago I was talking with a family member who is in
| wind power research. They were trying to convince me to start
| writing turbine control software because it is massively
| inefficient and naive.
|
| I was shocked at some of the optimizations they are lacking.
| hirundo wrote:
| "But in the new system, for example, the team has found that by
| turning one turbine just slightly away from its own maximum
| output position -- perhaps 20 degrees away from its individual
| peak output angle -- the resulting increase in power output from
| one or more downwind units will more than make up for the slight
| reduction in output from the first unit."
|
| I assume that this could also increase the speed of a cooperative
| convoy of sailboats, that have a good reason to stay close. I
| wonder if the fleets of sailing ships of Admiral Nelson's time
| took advantage of this. A few extra ergs of force in a sea chase
| could make a large difference.
| scrivna wrote:
| You see this in competitive dinghy racing. One person will
| intentionally starve their competitor of good air, so they know
| and could do the opposite if they wanted. Lots of sports deal
| with this "dirty air" concept like Formula 1 especially,
| regulations were changed for this season so the car in front
| produces cleaner air off the back so cars behind can follow
| better (which provides a better chance to overtake/better
| viewing spectacle).
| rocqua wrote:
| The idea here is 'stay out of dirty air better'. It isn't a
| real gain for the downwind turbines, just less of a loss. This
| concept has long been known to sailors. And I presume that
| sailing in convoys took this effect of dirty air well into
| account.
| jmartrican wrote:
| Serious question here. Why I see all these breakthroughs coming
| from MIT? Are they really heads and shoulders above everyone else
| or do they have great PR/marketing?
| jehb wrote:
| In addition to the other replies, it's also worth mentioning
| that they have an incredibly large endowment, worth $27.4
| billion last year, the fifth largest of any private university
| in the US. That's compared to an average of $1.1 billion, and a
| median of just $200 million, less than 1% of MIT's.
|
| Source: https://www.insidehighered.com/news/2022/02/18/college-
| endow...
| moistly wrote:
| There is really no excuse for the US to not provide every
| intelligent high school student the opportunity to enrol in
| MIT-quality education _for free_. And, for that matter, to
| enrol in high-quality trades programs, because we need people
| who can actually build, maintain, and repair, too.
|
| Imagine the technical and infrastructure improvements. We
| would _leap_ ahead by every metric.
| gostsamo wrote:
| At least in this case, it seems that MIT is only tangentially
| related to the research. The lead researchers are from Spain
| and India with financing from Siemens.
| RosanaAnaDana wrote:
| Its good marketing and I would keep an eye on what accounts are
| submitting these. Its practically a trope on HN at this point.
| Not to say that MIT doesn't do cool stuff, but there are few
| institutions as good at self promotion.
| photochemsyn wrote:
| If you look at the paper it's actually a collaboration between
| MIT researchers, Caltech researchers, a Spanish Siemens groups,
| and an Indian power company.
|
| MIT just has a more effective marketing division, it seems.
| Here's the Caltech press release for comparison.
|
| https://www.caltech.edu/about/news/tweaking-turbine-angles-s...
|
| > "Collectively, wind farms generate about 380 billion
| kilowatt-hours each year in the United States. If every U.S.
| wind farm were to adopt the new strategy and see efficiency
| increases similar to those found in the new study, it would be
| equivalent to adding hundreds of new turbines capable of
| powering hundreds of thousands of homes to the nation's power
| grid, says Caltech's John O. Dabiri (MS '03, PhD '05), the
| Centennial Professor of Aeronautics and Mechanical Engineering,
| and senior author of a paper on the project that was published
| by the journal Nature Energy on August 11."
| marktangotango wrote:
| Probably both, it is a top research university in the world,
| with a lot of smart people and funding. Also note the "T" in
| MIT stands for technology, they do tend to focus a bit more on
| practical applications and not just theoretical knowledge.
| koheripbal wrote:
| This only impacts wind farms when they are arranged such that the
| wind front passes over multiple turbines.
|
| Often, wind turbines are arranged in a line across the usual wind
| front, so turbulence isn't typically an issue.
|
| So, in this case, when wind passes over multiple nearby turbines
| serially, then there is a 1.2% gain on efficiency.
|
| Still a worthwhile deployment if the model is accurate. Needs to
| be tested.
| rocqua wrote:
| The 1.2% figure was a month long average from a real-world
| test. In certain conditions they got 32% higher efficiency.
| Presumably those are the conditions when the wind is blowing
| sub-optimally.
|
| Unrelatedly, from personal experience both onshore and offshore
| windfarms seem to be packed much tighter than in a line.
| briffle wrote:
| completely anecdotally, I have noticed in the midwest, its
| very common to have a large grid of windmills.
|
| But out west, some (not all) of them are placed along
| ridgetops in a wide line, with none behind each other.
| dylan604 wrote:
| Why go anecdotally? Here's photographic evidence:
|
| https://www.google.com/maps/search/wind+farm/@32.3343137,-1
| 0...
| koheripbal wrote:
| These rows are spaced far enough apart that I don't think
| the OP research would help as much. Even where they are
| clustered, they are at different elevations.
| dylan604 wrote:
| That was the point of the prior comment about seeing them
| strung out vs clustered. Obviously, location location
| location. West Texas wide open spaces means you can
| spread them out so they are not ideal candidates. I was
| just saying that rather than saying something
| anecdotally, you can make the claim with supporting
| evidence.
| hinkley wrote:
| Most importantly, anything that increases the minimum power
| production from a wind farm (on "bad days") reduces the need
| for base load power.
|
| You can only store so much power for interday variations.
| Everything beyond that takes fossil fuels.
| koheripbal wrote:
| I think the minimum remains at 0 - the no-wind today
| condition.
| hinkley wrote:
| No wind all day is quite a bit different from spotty
| wind. Any day with a little wind slows your withdrawal
| rate.
|
| And while you might not be able to decommission a peaker
| plant, one of the ways power gets around emissions limits
| is that the pollution is annualized. You can reduce the
| emissions of a plant by half of you can turn it off part
| of the year, so where possible they spin up the better
| plants first. Anything that keeps their next worse plant
| offline more helps the rest of us.
| im3w1l wrote:
| This made me try to imagine solutions to the no-wind
| condition, whether there is any control strategy that can
| work for it. And I laughed at the idea of one wind mill
| blowing at another to get a net gain of energy. But then
| I thought, is that really such an absurdity..?
|
| What if.. what if you can expend energy to "suck in" a
| nearby storm for instance? I don't know how _viable_ it
| would be, but at least it doesn 't seem to obviously
| break physical laws.
| sgc wrote:
| I get it. You want to store energy in man-made tornadoes,
| then discharge them slowly when wind calms down. So the
| optimal layout is circular. By adjusting the turbine,
| they can either feed into or pull out of the cyclone.
| Genius!
| HPsquared wrote:
| I think it's more like cloud seeding, trying to redirect
| a weather event (which is happening anyway) to a more
| fortuitous location.
| hinkley wrote:
| Stored hydro is basically this.
|
| I'd like to see stored hydro that was a little more
| environmentally friendly. Perhaps a series of floodgates
| where one area is mostly dry and another mostly wet,
| rather than everything being intermittently wet all year.
| photochemsyn wrote:
| Looks like they did some pretty comprehensive testing:
|
| > "In a months-long experiment in a real utility-scale wind
| farm in India, the predictive model was first validated by
| testing a wide range of yaw orientation strategies, most of
| which were intentionally suboptimal. By testing many control
| strategies, including suboptimal ones, in both the real farm
| and the model, the researchers could identify the true optimal
| strategy. Importantly, the model was able to predict the farm
| power production and the optimal control strategy for most wind
| conditions tested, giving confidence that the predictions of
| the model would track the true optimal operational strategy for
| the farm. This enables the use of the model to design the
| optimal control strategies for new wind conditions and new wind
| farms without needing to perform fresh calculations from
| scratch."
| fastest963 wrote:
| What about when the wind is tangent to installation line and
| blowing across them. Wouldn't they all rotate to face the wind
| and now be in front of one another?
| PeterisP wrote:
| The majority places have a strong directionality of wind due
| to the terrain, it's quite plausible that this place this
| happens very, very rarely (and the planners of that wind farm
| definitely took that into account).
|
| E.g. the first random example of a wind rose plot I googled -
| https://www.researchgate.net/figure/Wind-rose-plots-of-
| all-N... - is quite typical, where winds almost all times go
| one way or the opposite way, and very rarely in the
| perpendicular direction.
| Bilal_io wrote:
| I think placing them in a grid format, where each grid node
| gets a turbine. That way you'd have them aligned when the
| wind blows E<->W, S<->N, but also SW<->NE and SE<->NW even if
| they're x[?]2 away from each other in that case
| JoeAltmaier wrote:
| Wind farms in my state have grids of towers across square
| miles. So nearly every tower is in the 'wind shadow' of any
| number of other towers. This seems like a very suitable
| innovation here.
| timerol wrote:
| There are definitely a number of installations where this could
| be useful. My favorite example is Antelope Valley in Southern
| CA, where the turbines stretch out as far as the eye can see.
| The scale is absurd. 3288 turbines are there, according to
| https://eros.usgs.gov/media-gallery/earthshot/wind
|
| Streetview:
| https://www.google.com/maps/@35.0385954,-118.2567896,3a,75y,...
| rootusrootus wrote:
| That's interesting from the satellite view, seeing the
| various installations next to each other and various
| approaches to layout. Some lined up tight, some spaced out,
| some perfectly straight lines, some meandering a bit.
| koheripbal wrote:
| Browsing around, it looks like several have had a serious
| failure events...
|
| One example, but it's easy to find more... https://www.goog
| le.com/maps/@35.0727844,-118.2627452,139m/da...
|
| Are they really so fragile? It looks like maybe 2-3% of
| them have fallen apart.
| abathur wrote:
| I don't _know_ much about this, but:
|
| - I think they are fiberglass
|
| - IIRC they actually need to be locked beyond some safe
| maximum windspeed because the forces they're under are
| indeed sufficient to tear them apart. I guess if local
| conditions can change faster than they can be locked (or
| if the locking systems can fail?) with any frequency,
| then such damage might be common.
|
| - I do also wonder if something like a bird impact is
| common, and whether it's enough force to crack the
| fiberglass (or whether reverberations of the impact on an
| active turbine would cause trouble)?
| mgsouth wrote:
| I live in the Valley; we get some huge winds and gusts
| around here, especially along the north slopes. Once I
| repaired a blown-down wooden fence out in the county for
| the Nth time, "really" fixing it by bracing with a 2x4
| from the top to the ground behind it. Came back a few
| weeks later and the wind had jacked the whole panel out
| of the ground, pivoting on the brace's grounded end,
| pulling up fence posts buried three feet deep.
| WalterBright wrote:
| Is the fence solid? Perhaps make a slatted fence, so the
| wind can blow through it.
| mgsouth wrote:
| It's already slatted. TBH, the fence has never been
| properly repaired, due to materials on hand and a certain
| impatient father-in-law. The posts should be buried 4 ft
| deep and bedded in a 3-or-4 inch wide concrete base. But
| going to check on the place and fixing the fence is kind
| of a ritual now, a good excuse to get out to the country.
| Beautiful wide-open tranquility.
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