Just ten miles from Factor e Farm – 100 windmills of 2.1 megawatt capacity were installed over the last two years – with 100 more forthcoming. It’s quite a sight. I asked a couple of local farmers about them – and they told me that don’t like the new sights and slight noise. Apparently, people don’t like them here unless they are getting $3k per year in land lease fees if the windmill is on their land.

I love the sight. Each windmill is generating almost about $200 worth of energy per hour at full output if the energy is sold at 10 cents per kilowatt hour. On average, at 40% duty cycle, this translates to over $300k/year of electricity produced. It looks like a 7 year payback time, if each turbine costs $2M a pop.

I always think immediately what can be done right now at Factor e Farm. We actaully do have a favorable wind location at the northern end of the land. What to do? Stick this 50kW, 600 pound, $1300 generator on top of a 100 foot tall, $2000 mast and foundation supported by guy wires costing another $1000, use these blades at $50/meter for a total of $1250, another $1000 for mechanical components – and use open source power electronics of $1000 in cost to manage the juice – and your price ticket is $6550 for parts, or about 10 cents per watt of installed capacity if the turbine produces 50 kW. It costs the big guys about a dollar per installed watt. Sure looks good on paper.


  1. burritoboy

    Check out the homebrew wind turbines the folks at Forcefield have been making

  2. burritoboy

    Actually maybe it’s better to start from this url

  3. Nick

    Don’t forget your foundation cost, utility disconnect, licensed electrican fees, utility permit process in the mix. Oh yeah expect about a 10% capacity factor at your sight on the short tower you mention. Add it all together and I’d be amazed if you got a functional 50kW turbine up for $50,000. Which would be an 11.4 year payback.

    The fact is utility scale wind turbines benefit from economies of scale, and to date small wind has not made this work at all. Do readers of this site a favor and do your research before you go touting small wind as another cash cow for your site.

  4. Nick

    Well I’m at it let me cut to the heart of the economic matter of electrical power production, coal. Western coal goes for about $11/ton currently and at 9000Btu/lb, which gives you .61$/million BTU, where as a gallon of gas has 125,00 BTU’s @ $3.20, or $25.6 per million BTU. Bottom line is coal is insanely cheap and even with top heavy centralized organization you really can’t compete economically with it.

    So you want to make money why not net meter a coal combined power unit. The economics are gauranteed to work, and if you utilize waste heat you are allowed to net meter to your states limit since it is an energy improvement.

    The system could be a downdraft gasifier coupled to old pickup engines with the raditator heat going towards your thermal load. The exhaust could also be cleaned up with a catalatic converter and baghouse filter so that you could be as clean or cleaner than the big guys.

    You think I’m joking but my opinion is our economy is based bottom line on cheap energy and its doubtful any other energy source can really compete with this.

  5. […] Windpower | Open Source Ecology […]

  6. Marcin

    Nick, good comments. We’re talking materials only in our figure. Foundation cost is included for $1k, which gets us 10 tons of concrete; licensed electrician costs can be zero if this knowledge is open source. This still leaves us with utility connection costs, which would be negligible when we have an open source grid-tie inverter (included for $1k (and otherwise costing 10 times as much)). So this still leaves us at 20 cents per installed watt even if we add another $3.5k to our price. This is wholly consistent with the typical reductions of cost obtained via open source – here factor of 5 compared to the Big Guys. We have demonstrated such reduction with the CEB press, though it’s true that the particulars of wind power may make our extrapolation invalid. We are hopeful because the significant cost reduction has been demontrated by many hardware projects, of which RepRap is most significant. It seems that a general rule is followed – the higher the IP cost, the greater the savings. Thus, the general feature of ‘cost reduction via open source’ is sufficient to be optimistic in any project. The question remains, is wind power not open source? Absolutely not. There are many inferior designs out there, but when it comes to a windmill that means business – I have yet to see one that qualifies. It seems to me that the 50kW scale is just the right size for economics to make sense, and to be replicable. The size is sufficiently manageable that a relatively low capital infrastructure is needed for installation.

    The capacity factor is an issue wherever we are. The big wind farm here is 40%, and 10% factor is probably right for us. All things considered, if we are getting 5kW on average from the turbine – that would be major success. It’s a payback time of 2.5 years, with $4k in electrical value generated per year.

    In our line of business, Henry Ford’s comment is typically true – “Whether you believe you can, Or you can’t, you are right”

  7. Nick

    Two more technical details to point out. One the blades you list have a maximum length of 6m per blade giveing a maximum diamter of 12m. This is not enough collection surface area to yield anywhere close to 50kW peak output.

    Secondly the generator you list is an induction motor, which is actually in my opinion the preferable way to go. This howver requires that the generator have a some sort of control scheme to engage and disengage line voltage to the generator as the rotor comes in and out of wind speed. It does not however require an inverter, which is only for a permanent magnet style generator. The control scheme for an induction generator would be the cost of a PLC, plus soft start feature, plus anemometer, plus brake and misc sensors. Hardware could be had for maybe a grand, programming would take some serious time.

  8. Richard

    For remote and low-power applications, you may want to consider wind belts. They can be made for the cost of coal per watt. It would make for a very fun and informative workshop to pump out a bunch of these.

  9. Gordon

    Simplicity maybe the best way to go. hope this link helps.

  10. Gordon

  11. Mitra Ardron

    There are a number of other things you’ve got to look at to get the total cost – and to compare apples & apples.

    For example, I don’t see in the description above anything to do with braking – a substantial part of the mechanics in a wind turbine are to do with how to deal with extremes, in particular what to do when the wind goes up to double the design speed.

    You’ve also got to look at startup speed, if youv’e got too much torque in your generator, then its not going to run at low speed – might have a better cost/max-watt, but cost/kwh will also depend on how efficiently your generator is capturing winds at the low-speed; and how long it can keep running at high winds.

    You’ve also got to consider the substantial torque on the tower when that thing starts or stops. I’ve seen substantial gear inside big turbines just designed to handle that.

    I’m not an expert, so there are undoubtedly other factors that push the costs up for the big-guys that might, or might not, apply to you, and it would be useful to publish a list of where you are getting savings – i.e. what you are NOT doing, and why.

    1. Marcin

      Have you seen the mechanical braking via blade pitch adjustment mentioned in the post? ( .

      The other issues are all true and to be determined in practice. Do we know what will happen in the future? All we know is that we have demonstrated with the CEB press that we can produce the same performance at 5-15 times lower cost to the user.

  12. Mitra Ardron

    Thanks Marcin – I hadn’t seen that post – you’ve got two issues to deal with on high-winds, a) slowing it down b) dealing with sudden changes and the impact on the system from that. e.g. larger systems talk about wear from “micro-welds” as the change in pressure is enough to weld the gears together then tear them apart causing significant surface wear.

    Please don’t misunderstand me, I’m just pointing out issues to pay attention to – sounds like youv’e already thought of some of them. I hope you can achieve these lower costs – especially in something that others can replicate, and with similar performance (i.e. cost measured in kwh not peak-kw)

  13. Olivia Miller

    actually it is not that hard to setup wind farms, the only problem is that it requires lots of capital investment..“

  14. Stefan @ KombinatG

    I visited a 18kW windmill in Sweden this year, the head and blades (with pitch control) where self-built with use of many standard and industrial parts.

    I build a windmill last year and earthscrews for the tethers are just perfect and easy to build.

    There are not much experiences for >10kw selfbuilt-systems, I suggest to start with smaller ones to collect experiences.
    A windmill should survive 50m/s windspeed, and all parts need to be calculated and constructed very well for this.

  15. Nick

    Don’t know if you guys have postponed any near term small wind project, but I’d like to suggest you check out otherpowers wind section

    I’ve seen this design in action and its solid, easily built and potentially competitive with CNC manufacture of blades frames, and some sort of automated generator winder. The biggest thing though IMO is that for small wind to be competitive it should be put up on a tilt up tower. I saves a big chunk on up front capital cost, and I personally don’t care for climbing the small little 120 foot towers that move around in the breeze.

  16. alphydan


    Turbines in the 50kW range for 7m blades are perfectly achievable (and were so 20 years ago). However, a 14m-15m rotor is some serious stuff. You can have a look here at some specifications of Danish turbines from the 80s: 65kW, 55kW

    Concerning cost The Big guys, are also around 50c/W installed see slide 21 (in fact they are below that). The reason they sell at $1 is to cover labor, research, capital costs … and make a nice profit.

    Should we start a bettermeans project to develop this cheap 50kW machine, or will the wiki be enough?

    1. Marcin

      If you would like to be the project manager for the 50 kW wind turbine, please contact me.

    2. Marcin

      If you’d like to be the project manager for the 50kW wind turbine, please fill out the short Team Culturing survey,, and please contact me when you’ve done that.

  17. Josef Davies-Coates

    Hey Marcin,

    Just wondering, what is the reasoning behind going for 50kW and not more/ less? I see you were interested in 6kW before. What has changed.

    I’m intrigued because someone is asking me if I’m interested in getting involved in a new co-op in the UK manufacturing (potentially open source) 50kW – 150kW turbines!



    1. Marcin

      At the 50kW minimum scale – we get into excellent efficiency of scale, while remaining in the realm of easily-accessible generator heads.

      Tell me more about the co-op.

  18. James Clark

    I’ve been look into this tech as well, and for this scale of manufacturing, vertical rotation turbines is probably the way to go. They start in much lower wind, are more durable (less fighting gravity of the long axis, and can withstand much stronger wind speeds), and can be, with some rather crazy math and cad-fu skills, be modeled fluid-dynamically as to direct airflow downward to the next set of blades. It would also allow you to print the blades on the 3D printer, saving additional resources. It would require a rectifier though.

  19. Josef Davies-Coates

    Marcin: that plan (AFAIK) for the co-op is to manufacture and sell turbines. One good thing about the UK is that we have a legal structure ideal for doing real crowdfunding where people can really invest/ buy shares, not just donate. For full details see

    There are various “model rules” that can be used to start such a Cooperative or Community Benefit Society, but my favourite by far are the Multistakeholder Cooperative Society Rules, aka the Somerset Rules, see

  20. Oren Beck

    Thinking big and using “already accepted” Tech does have some merit.

    I’m gently suggesting a revisiting of “Small Is Beautiful”

    55 Gal drum materials to make Savonius AkA VAWT wind machines can produce a “properly scaled” power module. Electric’s a nice power handling medium, though direct mechanical uses like water pumping and air compression have their own set of merits. Simple is GOOD at times.

    A wind unit, Lifting water to an elevated storage captures both potential energy in the “fall height” of that water, and it’s AVOIDED energy expense for irrigation or other demand uses of the water.

    Like an independent potable water cistern for every dwelling unit or site needing that.

    Same with Gravity Tank FIRE suppression systems.

    So- that<500W Savonius's trickle charging mode so to speak- may end up being a huge quality of life booster and project enhancement tool.

    Call the closing scene " A Local Grid"

    Redeployed forklift battery packs that are babied by never using more than 15-20 charge= never allowing a discharge to take the battery BELOW an 80% SOC might last a very long time if watered properly etc, Yet- some intertie cables between dwelling units and powered outbuildings makes a more robust LOCAL grid. and keeps capital costs down by using Common, Off The Shelf components like EU spec Inverters so tie cables run @ 230V instead of 120. No fancy custom stuff required. Same with Battery chargers- EU spec 220/50HZ chargers put out the same 12-48 Vdc to top up batteries.

    For now- it's a case of small capital investment making BIG lifestyle imporovements.

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