Kite, airborne and high altitude wind energy blog

New Laddermill Video from Delft, New international conference

2011-03-02T08:37:00.000-08:00

TUDelft flying high, Next AWEC conference in europe

Quick post today, here's a new video showing the great progress being made at TUDelft. They've made good progress on the kites working with Mutiny, you can clearly see the modified attachment points and bridle on the in-flight video. This video also shows the teams first autonomous controller deployed on the kite.

Also should have mentioned ages ago, the 2011 Airborne Wind Energy conference, awec2011 is at KU Leuven in Belgium at the end of May, keynotes lined up include the elusive Stephan Wrage from Skysails aswell as Corwin Hardham (Makani Power) and Wubbo Ockels (TUDelft).

Airborne Wind Energy on TV and at TED

2011-01-30T08:27:00.000-08:00

Great exposure for Ampyx, SwissKitePower

After a protracted blog-silence whilst I finished my phd thesis (now submitted!) I'll now be updating the blog again whenever there is news to report. 2011 should be an exciting year for Airborne Wind Energy, with more new startups, established energy and engineering firms moving in and some exciting projects in the pipeline.

To start things off, here's a video featuring Swisskitepower which is to my knowledge the first feature on Airborne wind energy on French TV, congrats to Corey and the team for the publicity!

Also Bas Lansdorp from Ampyx Power had a slot at TED Amsterdam, it's a brief talk but has some nice shots of the kiteplane and probably the best shots of their winch system to date. They seem to be making good progress and Bas is a great ambassador for the technology.

Good funding news both side of the Atlantic

2010-09-14T05:02:00.000-07:00

Ampyx, Makani secure governent support

Two more sets of funding have been announced this week, Ampyx Power, the Dutch spinout from TUDelft, who have been working on their rigid wing, ground based power generation concept (see pic) since '08, today announced new EU funding, to continue their autopilot development and the scaling up process.

Makani power, the Alameda CA based flying generator startup, also have been announced as recipients of c.$3m of ARPA-E funding, see their announcement for details.

Another University Project, Cool Skysails Video

2010-09-13T14:14:00.000-07:00

No time to write much today but here's a video from the group at Rowan University:

The kite doesn't appear to be instrumented and I can't see a camera so i'd guess that the control is either passive or manual? I'll update this post if/when I find out.

On an ever so slightly larger scale, here's a video taken from a small airplane of a Skysails system in operation. The scale of the kite is seriously impressive. I'm not sure I realised how close-in the pod is kept to the kite. For some reason the kite is being flown at a higher angle than I would normally expect, maybe the ship is turning/tacking...

Either way, a glimpse of things to come I'm sure!

Unfortunate name convergence, 2 x Skymill, 2 x Kitemill !!

2010-09-02T06:13:00.000-07:00

Couldn't resist a second post on this. The French project below I found because I was googling for info on the Norwegian startup Kitemill. The french project is called .... Kitemill!

So instead of working like I should be, I googled for some info on Skymill, a group in the states that were at the HAWP conference last year with a cool concept using an autogyro as a kite to drive a reel at ground level as a pumping generator (if i remember right). Instead I found an Italian project that uses a kite and balloon to raise a propellor coupled mechanically to a generator at ground level, not convinced by this one I have to say! The video on the website will save me any more typing to explain.

Maybe people are going to have to be a little more imaginative with their names, there is hope though -google is not called 'SearchPage' is it? Alternatively I can save future startups time and they can pick a name from this list:

SkyGen
SkyPower
KitePower
AeroPower
AeroGen
SkyTech
Altigen
LiftTech
Crosswind Power
Crosswind Energy
Elevated Wind Energy
etc...

Feel free to add your own in the comments!

Windlift Progress, new student project

2010-09-02T05:41:00.000-07:00

Still have about 10k words to go on the thesis but the end is in sight and seeing as the wind hasn't picked up enough yet to go testing I thought it might be time for a quick post.

Here's a video showing the new prototype from Windlift, which is a departure from their old sled system to a reel based device. The test shows power peaking at 3kW at 8-12 mph though I'm not sure how high that wind measurement was taken or the size of the surf kite being used. Either way it shows some great progress over the last year. The base seems to be passively rotated and its inertia means that it's not following the direction of the kite too closely, (we had this same issue on a proto system here at Sussex) but it's not going to be too hard to sort that out.

I also found this website for a student project that I hadn't seen before at the Ecole Centrale de Lille, also for a kite based system. I saw this graphic of the system concept and was impressed to hear that they had built it.

This video shows it being tested. Having seen the scale, You can see how it was affordable as a student project! They have an interesting way of doing the steering at ground level.

3MW Kite generator in build ?!

2010-08-03T14:07:00.000-07:00

World's most powerful kite turbine?

Just saw this video today featuring the Kitegen project on the Italian TV show 'Superquark'.

At about 2 mins 45 and 4 mins 50 you can see the system that featured in their last CGI animated visualisation in actual construction. Note that I actually have no idea if this actual build is supposed to be running a 3 MW generator, but this article on their website said that this was the case for the STEM concept.

Wow, at this point I should point out that Kitegen have been testing the largest capacity airborne wind energy system that I know of at 30kW for some years (data for auxiliary power generation capacity of the Skysails system is not available). They were the first commercial AWE project running if Skysails is discounted, and they have a considerable patent portfolio.
But... 30kw to 3000 would be an ambitious step. I'd love to know more about the motivation for the design concept, especially the rotating boom, which presumably would need active control, or at least damping to prevent its inertia taking it in an opposite direction to the kite at each extreme of the lying 8? Would a tower not be simpler? Also, it would be great to know what kite they are going to use, an 500sqm LEI doesn't seem particularly practical, and the L/D is not great. I guess we'll have to wait and see!

If any readers out there speak Italian and can glean more information from this than I have please enlighten us!

Back to light entertainment, new Makani site, new companies, conference news

2010-08-01T11:02:00.000-07:00

So after that painful exposuse to some math, here is something nice to look at, Makani's rather fetching new website . There's a new video I hadn't seen:

Which is nice to see, not sure what the wing area is, but you can see the power output and windspeed in the plot, if you managed to keep watching after that stomach churning on-board cam bit. I might do a post on the content of the new site at a later date.

Also here's a new company: Kitemill. I know not alot about this project but given the name I would expect ground generation with a kite? And another one : Altaeros Energies, who don't have a site yet but this article
shows a logo and the scheme of operation which is basically a windturbine elevated with a buoyant & lift generating, passively stable enclosure/fairing like this:

Final exciting news is that Jianjun Zhang of the snappily titled: Guangdong High-Altitude Wind Power Technology Ltd. will be at the AWE conference. I'm sure everyone is keen to hear about that project. Registration is open for the conference and I would definately recommend going. The list of speakers looks fantastic.

Ok ok, here's the last bit: Flygen vs Groundgen the finale

2010-08-01T10:37:00.000-07:00

Has it really been 2 months? Sorry for the lack of updates, I have been desperately trying to bring my work together for my Dphil thesis which is due to be submitted in 53 days exactly and I'm still, hmm about 25k words and about 10 flight tests short!

Here is some of the ground gen/ flygen comparison brutally culled from my post on the awe list and from Loyd's wonderful paper.

Ok, some pros and cons. This is assuming that for a flygen you would have a hard wing and for a groundgen a soft wing. Uwe at TU Delft pointed out quite correctly that you can have a hard wing groundgen like that at Ampyx that will have some of the advantages (and disadvantages!) of both approaches.

Soft	Hard
Harder to get high L/d	Easier to get high L/d
Lighter	Heavier - inertial loss?
Less prone to weight penalties on scaleup	More prone to weight penalties on scaleup
Cheap	Expensive
Subject to wear, esp when fluttering	Excellent wear characteristics
Under-actuated	Excellent control authority
Difficult and comp expensive to model- Multibody approach?	Can be modeled through conventional techniques, i.e.Neuton/Euler or Lagrangian in real time
Pack down small	Don't pack down
Could deform to match conditions	Must operate in all conditions
Can do ground gen	Must run power down cable
Severe cable wear from repetetive bending - if doing groundgen	Cable bending frequency is low - if doing flygen

After that, here are some gems from Loyd:

Basically this is saying that the power scales linearly with air density but with the cube of the apparent windspeed. Translation: Going fast is dispropotionately rewarded, when going high air will be thinner but this should be more than cancelled out by faster wind.

Next....Speed, and hence apparent wind speed is going to be affected by the lift/drag (glide) ratio of the wing, less drag meaning more speed. According to Loyds analysis this is another exponential effect - check it out here for the drag(flygen) mode, where:

This graph shows the exponential scaling showing how important efficient wings are. It looks linear but the scales are logarithmic ok!

This next graph shows that the peak power of the lift(groundgen,Fc) and drag(flygen,Fd) modes are pretty much the same. Groundgen reelspeed wants to be about 1/3 of windspeed, and there is a broad peak for the flygens in terms of the ammount of drag you put on the wing, which gives a fair bit of operational leeway.

Now, Loyd does miss some things out for that comparison graph: tether drag: assuming that you have an unfaired ( a normal) tether, it will begin to dominate the drag of the system as your l/d on the wing gets higher and higher, so you won't see anything like the advantage shown by the graph.
Also Loyd assumed weightless wings.... why does this matter? Because during steering you are pulling the wing away from the direction it's is going, you will be using some of the energy from the wind for fighting the wings inertia. The heavier the wing the greater the loss.

Ok there ares a load of other things that could be incorporated to a model but that's enough for one day. So.. the conclusion is..... There is no clear winner, each approach has advantages and disadvantages, the 'best' solution won't neccesarily win the market, it will be a balance based on capital cost, performance, durability, safety, public acceptance, and more. In short, there's no free lunch.

Groundgen/Flygen Comparison Weekend - 2

2010-05-30T11:49:00.000-07:00

Ok, as promised, here is the second part, Flygen or 'Drag Mode' machines, here is a video that Corey of SwissKitePower pointed me to (thanks Corey!), featuring one of Makani Power's wings in much more detail than I had seen previously. Let get straight to it.

As you can see, they have moved well away from the fabric kite, groundgen approach they took at the start and the system now much more closely resembles a UAV. There is a strong dihedral, (the wings point up) on the horizontal stabilisers at the back there, and a lighter diherdral on the main wings. The 'fuselage' for want of a better word seems to be a large composite pole, I don't know if it really takes two people to lift it or if they are just being careful.

The next obvious video to post would be of Joby Energy's prototypes, but there are no embeddable videos up on youtube so you'll have to look here instead. There's a couple of nice video's of really agile free flight and self powered VTOL which I would assume is more scaleable than being shot into the air with compressed air, but what do I know?!....(edit 02/aug/10, makani's site now shows a full vtol concept with landing cradle, so clearly they are not planning on relying on the current scheme indefinitely!)

I'll do some basic comparison between the 2 approaches tomorrow, with a bit of reference to Loyd to bring it all together.

Groundgen/Flygen Comparison Weekend - 1

2010-05-29T08:36:00.001-07:00

Ground-generating Configuration Videos

This weekend being a holiday here in the UK, I'm going to take some brief breaks from a hectic programming schedule to post some video links. Part of the reason I'm doing this is to highlight the difference between generating on the ground, and generating in the sky, what Loyd called the 'Lift mode' and 'Drag mode' respectively.

Airborne wind energy is still in its infancy but I get the feeling that this difference is quite crucial and it will be really interesting to see how each stream matures over the next few years. Both schemes have some common benefits and challenges but also some very definate advantages and disadvantages. After I've shown both sets, I'll list a few of these as I see them and it would be really great to get some feedback from the surprisingly ever increasing number of readers.

The first video is Stefano Milanese from KitEnergy talking about some tests performed with their generator on a boat.

and here is a recent test from the laddermill team at TUdelft, they have a new website by the way at www.kitepower.eu. It shows them maxing out their generator at 20kW with a 25m SLE kite, there is also load of other interesting videos on the Laddermill Youtube channel so check them out.

Hopefully you readers will get impression of a growing maturity of kite energy, both in hardware and also operationally. Please note that TUDelft have air space authority for their testing at such altitudes - don't try that at home!

2010 International Conference

2010-05-09T09:10:00.000-07:00

Details of this year's Airborne Wind Energy conference, new consortium anounced

Sorry everyone for the terribly long wait since the last post, it has been all hands to the decks since February, having said that, there will be some exciting footage coming up soon.

The news today though is the details of the 2010 Airborne Wind Energy Conference (Let's not dwell on the retreat from high altitude shall we!) are out. Here is the link to the site: http://www.awec2010.com .
Key details:

Conference Dates: Sept 29-30, 2010
Conference Location: Stanford University, CA
Submit speaker request by: (not explicit) ASAP

And also there is a new international Industry Organisation, the Airborne Wind Energy Consortium : http://www.aweconsortium.org . It's about time this happened, it makes sense for those kind of advocacy and communications activities to be done collectively for the whole industry.

CMNA power, new startup

2010-02-11T10:36:00.000-08:00

Another US stealth startup, another marine kite company

Only a quick note today, but in one of my sporadic googling sessions I found a new start-up. And I also found out about another marine propulsion startup. It looks like I'm going to have to update that graph sooner rather than later!

The power producer is called CMNA power, their site is amazingly tight-lipped ( boring!) but their incubator at the University of Texas is less shy (hooray!). As this is all I can find, we'll have to wait to see if they have flying or ground based generators.

Much more informative is the site of AirplayKitesailing, who are developing kite systems for catamaran racing, but with an eye on the yacht market later down the line. They were founded by a couple of TUDelft graduates. I'm hoping to meet up with some of these guys later in the month when I'm in Delft, I want a a ride on one of those cats!

Here's a video:

Festo Cyberkite

2010-02-02T09:01:00.000-08:00

Kite Energy in Brushed Aluminum

As the day here is wet and gloomy (but windy!). I thought I'd write a post about my current favorite kite energy project. It was done by a company called Aeroix for the German industrial automation giant Festo, using Festo hardware to construct the groundstation.

As a development system it is almost perfect in that it is not really intended as a generator, but rather as a platform to test the control and tracking system, and on which to trial new kite designs. That is the level where the key development questions can be asked without spending unneccesary money.

Aeroix worked with the technical fabrics that they provide to German kite/paraglider company Flysurfer/Skywalk amongst others, so as to have a buoyant helium filled kite as well as standard ram-air twin-skin bridled foil kite.

Another interesting thing about this project is the is the shape of the kite which echos the bio-mimetic wings Festo have had built for other projects. The bridle is definately complex as you can see in the video. I'd like to see lift and drag curves for the kite but obviously they aren't giving anything away!

Before you get bored, here's the video:

One thing you might be wondering about is why 4 line control from the ground? Well, I guess it wouldn't be much of a showcase for festo's automation gear if all the fancy hardware was 50m+ away from you up in the sky. Aeroix are pushing forward with the project with a more specific generating system called Enerkite, and are sensibly avoiding all talk of MW and planning incremental scaleup. Finally someone with patience! Good luck to the Aeroix team, I can't wait to see their progress.

UK Feed In Tariffs Anounced by DECC

2010-02-01T04:59:00.000-08:00

UK finally gets FIT

DECC finally anounced the feed-in tariff bandings today with remarkably positive results. Here is their press release.

In short, it works like this: "Households and communities who install generating technologies such as small wind turbines and solar panels will from April be entitled to claim payments for the low carbon electricity they produce."

This works even is you consume that power yourself. If you consider that the wholesale value of a kWh is about 6p, or 10-12p for domestic rates, the payments work out at a surprisingly high multiple. The UK small wind sector must be overjoyed. The rates do taper down with installation size to roughly match the ROC price by >500kW

Here are the rates for wind only:

Tariff levels for electricity financial incentives
		Year 1: 1.04.10- 31.03.11	Year 2: 1.04.11- 31.02.12	Year 3: 1.04.12- 31.03.12	Life (years)
Wind	≤1.5kW	34.5	34.5	32.6	20
Wind	1.5 - 15kW	26.7	26.7	25.5	20
Wind	15 - 100kW	24.1	24.1	23.0	20
Wind	100 - 500kW	18.8	18.8	18.8	20
Wind	500kW - 1.5MW	9.4	9.4	9.4	20
Wind	1.5MW - 5MW	4.5	4.5	4.5	20
Existing microgenerators transferred from the RO		9.0	9.0	9.0	to 2027

The 20 year guarantee with index linked payments is great for long term security and the BWEA did a great job of lobbying to stretch the bands favourably i.e there is no 50 to 250kW band as earlier proposed.

But here is the but...., note the phrase 'Householders and communities', this presumably is excluding businesess, meaning that High Altitude Wind Energy is still effectively penalised compared to other emerging renewables technologies ( see my earlier ~~rant~~.. er I mean post about the RO banding). Still, this makes a 99kW or a 499kW system look damn attractive to a landowner or island community.

Kite visual tracking progress

2010-01-31T05:38:00.000-08:00

Tracking kite position in real time by camera

Here is a little clip showing some basic kite tracking software that I wrote. I'm upgrading it now for improved accuracy and an orientation estimate.

UK gets FIT

2010-01-31T05:34:00.000-08:00

Big Day for UK renewables tomorrow?

The details of the UK feed in tariff (FIT) are widely expected to be released tomorrow bu the Departrment for Energy and Climate Change. Designed to complement the Renewables Obligation (RO) by supporting deployment of renewables at a smaller scale <5MW.

The mechanism is guaranteed grid access at a guaranteed price which tapers off as the size of the installation increases so that between 500kW to 5MW it is essentially the same as the ROC price bonus.

I'll post the details here as soon as they come out.

Growth in high altitude wind

2010-01-24T06:05:00.000-08:00

Explosive growth in high altitude wind energy

So below is a graph showing my tally of institutions, i.e. companies and universities, working actively on high altitude wind energy. I'm including Marine propulsion. When I have the time I'll try and do a similar thing for investment and for people employed. Note that the figure for 2010 will doubtless grow as I find out about projects that I have been hitherto ignorant of and as new projects get going.

Big news from China

2010-01-21T10:29:00.000-08:00

China's first high altitude wind energy project has just been publicly announced.

Worth 400m yuan, or $58m dollars, this article mentions 100,000kW or 100 MW which seems too large scale for a single device, will this be the first HAWP windfarm?

The article says this:

On “2009 International Clean Energy Summit Forum” held last October, Dr. Zhang introduced his core technology principle: the kite ascends like a glider by virtue of wind, generating pull, thus pulling cables, and driving generators to generate electricity; when the kite ascends to the maximum height, the angle of the wings of the kite will be adjusted by the control system to make it descend with its own weight. Then it ascends again to supply electricity, and repeats.

This seems to suggest that the project is for a relatively simple AOA mediated pumping system, generating on the ground, with no dynamic flying, but details are very thin. The article mentions wind tunnel test facilities. Projected costs per kWh are projected to be 0.22yuwn/kWh vs 0.36yuwn/kWh as a regional average (coal dominated), which would be very impressive at such a large scale given the immaturity of the technology.

This is really interesting and I'm looking forward to see some details, as the lead scientist mentioned-Dr Zhang, has no publications relating to HAWP and I can find no reference to the summit he is supposed to have presented at. The investors Pre-ipo captial partners, have a Chinese only website so no accessible details there either.

Thanks to Joe Faust for this news.

High Altitude Wind Energy Penalised in UK renewable incentive scheme

2010-01-21T06:17:00.000-08:00

High Altitude Wind Misses out in UK Renewables Obligation

'Shock' bulletin, goverment advisors class a brand new renewable technology, accessing a hitherto impossible and incomparably larger resource alongside 120 year old horizontal axis wind turbine technology, that will soon be obsolete.

A source within DECC told me that High Altitude Wind Energy will fall in the 'established technology' band, when it patently is not. Why? Well it seems that the classification is driven by language and not by the criteria that DECC claim to use, which are:

potential to contribute to penetration of renewbles into the energy mix
underlying cost of generation
novelty of tech

This is the clear intention of the Renewables Obligation and the Reneable Energy Strategy 2009, so here we have the first renewable tech with the potential to deliver energy cheaper than coal, which desperately needs support in the UK, but wait, it's on shore and it is a wind device, so no, we'll ignore our repeatedly stated criteria, and unlike every other novel system it will be denied the higher funding band.

Yet another opportunity scuppered, yet another own goal for the UK government, hooray for Kafkaesque lunacy....

Companies involved

2010-01-21T04:11:00.001-08:00

Some key players in high altitude wind energy (alphabetic)

I thought this might be useful to give an overview of who is involved

Academic:

CCNR, Sussex University UK

ETH/FHNW, Switzerland

KU Leuven, Belgium

Rowan University, US

TU Delft, Netherlands

Universita di Torino, Italy

Commercial:

Aeroix, Germany

Alstom France/Switzerland

Ampyx Power, Netherlands
Joby Energy, US

KiteGen, Italy

SkyMill, US

KitEnergy, Italy

Makani Power, US

NTS, Germany

SkyWindPower, US

Windlift, US
Zhang Jianjun's Project, China

Marine:

KiteForSail, US

KiteVes, Italy

Skysails, Germany

Unconfirmed by companies concerned:

Vestas, Boeing