Purchasing new hardware? Read our latest product comparisons

Is this the largest rooftop wind installation in the world?


August 17, 2012

A newly opened wind farm on the roof of the Oklahoma Medical Research Foundation is claimed by turbine suppliers Venger to be the largest building-integrated wind farm in the US

A newly opened wind farm on the roof of the Oklahoma Medical Research Foundation is claimed by turbine suppliers Venger to be the largest building-integrated wind farm in the US

Image Gallery (15 images)

A newly opened wind farm on the roof of the Oklahoma Medical Research Foundation is claimed by turbine suppliers Venger to be the largest building-integrated wind farm in the US. But might it be the largest in the world?

On June 22, 2012, wind turbine manufacturer put out a nondescript press release with the headline "Venger Wind Farm Installed on Roof of Oklahoma Medical Research Foundation (OMRF)." Welcome, but at first glance, not particularly ground-breaking news. Rooftop wind installations of significant capacity are relatively rare, but not so rare that a new one is likely to grab many headlines beyond local news coverage.

But a second look reveals, four sentences into a lengthy opening first paragraph, the following nugget of information: "the project is the largest building integrated wind energy system in the US." Yes, this appeared in the first paragraph, but with the sheer volume of press releases put out on a daily basis, this may as well have been written in Hittite. Talk about burying the lede. Credit must go to Inhabitat's Timon Singh for spotting this significant detail (assuming that's where he saw the story).

But enough about the subtleties of press release writing. Just how large is "large?" One hopes and assumes that by size, Venger is referring to installed capacity: the power the farm is capable of producing at peak output. The roof of the OMRF is now graced with 18 of Venger's 18.5-ft (5.6-m) V2 vertical-axis wind turbines. Each has a capacity of 4.5 kW, giving the installation a theoretical capacity of 81 kW overall. As rooftop installations go, that's certainly nothing to be sniffed at. As a basis for comparison, the three turbines integrated into London's Strata residential block have a combined capacity of 57 kW.

The cut-in speed of the turbines is 8.9 mph (or 4 m/s). That's the wind speed required for the turbines to even begin generating power, and is quite high compared to other wind turbines designed for urban conditions. The McCamley turbine we looked at recently begins to be productive in winds as weak as 4 mph (1.8 m/s). In Venger's favor is that they are sited on the 130-foot (40-m) tall OMRF, where wind speeds are certain to be higher.

An OMRF press release says that the turbines are projected to produce 85,500 kWh of energy per year, equivalent to seven average-sized American homes (and the amount of energy generated were the turbines to run under ideal conditions for 1000 hours.) Refreshingly, the release also points out this will not be enough energy to meet the OMRF's needs, but doesn't let us know what proportion of its demand that would cover. Strata's turbines (to use them as a yardstick again) were only expected to meet 8 percent of the building's energy needs, and you can bet that the OMRF houses more power-hungry gear than a mere tower block.

Interestingly, Venger isn't merely claiming this as the largest rooftop installation in the US, but the largest building-integrated installation. As most building-integrated installations will be on the roof, this isn't a huge distinction, but it's a slightly larger subset of wind turbines all the same. Turbines can also be mounted on building facades.

Inhabitat in its coverage calls this the largest rooftop installation in the world. We're happy to go along with that, unless anyone out there can point us to anything bigger still.

Sources: Venger and OMRF, via Inhabitat

About the Author
James Holloway James lives in East London where he punctuates endless tea drinking with freelance writing and meteorological angst. Unlocking Every Extend Extra Extreme’s “Master of Extreme” achievement was the fourth proudest moment of his life. All articles by James Holloway

I think those could also be called art - they're cool looking and, I think, add some visual appeal to the building.


Notice the lights that shine on the turbines at night from below. Looks pretty but will consume power.


Years ago a company was going to build a highrise in a urban area NY city if I remember correctly and for mostly for style they were going to have the building sitting on pillars leaving pedestrian traffic unimpeded across the property but wind tunnel tests showed that on breezy days the wind going under the building would be at hurricane force. The building went up without the plaza. The point being that if instead of making the wind farm an afterthought you design the building around it you could achieve a much greater energy output without affecting the practicality of the building.


Bahrain World Trade Center has some MW turbines integrated.


Innovation. eXcellence. Simply Delivered!

Amrut Nerlikar

wow, no talk about off grid

Eric Malatji

re; Eric Malatji

To go off grid you have to produce power equal to use The press release states that this is not so.


It figures that this would come out of a bloated medical budget. Is it being used for decoration, or to "prove" that wind power is uneconomic?

Bob Stuart

Looks like a bizarre mutant barber shop. More show than go, I would suggest.


How about the Pearl River Tower in China ? It is almost self sufficient in its energy needs.


Sadly another scam as these vertical wind turbines as all other VAWT's can't because of basic physics every be cost effective because they put out little power/$ or lb.

So far only 2-5 blade normal HAWT's have a shot at cost effectiveness and even then they have to be really good.

If RE is going to be big, and it will because when done right is already the cheapest electric source for homes, buildings making their own, we are going to have to weed these scammers like this company out and even put them in jail for fraud as it's just stealing by a different name.


@jerryd: one-on-one, it is true that VAWT is less efficient than HAWT, but you can place VAWT units much closer together, so as a system they produce more net power per area of deployment. The big reason most renewable projects fail is due to not enough thought goes into how the entire system will perform. VAWT is less prone to failure, and we're now seeing HAWT wind farm failure rates of 20%, as the big props and generators undergo far more stress than a VAWT unit experiences.

Pat Kelley

i like the concept of wind power, but there is no mention of what this cost, the ROI, the maintenance costs, or if it will ever pay for itself.

Larry Clement

re; jerryd HAWTs have to be alined with the wind, every video that you have seen were the blade strikes the tower the wind had shifted faster than the windmill could adjust. They also throw broken blades a lot further than VAWTs. VAWTs can also be engineered so that they loose efficiency as the wind speed increases so as to prevent overstressing the gears and generator.

re; Larry Clement The will probably come out ahead but I think that an energy capture device on the sewer would be more profitable.


Ok so how far off is the math? theoretical 81 kw instantaneous power output from entire installation, given an approximate 8760 hours/year should be 709 MwH (theoretical annual)

"An OMRF press release says that the turbines are projected to produce 85,500 kWh of energy per year, equivalent to seven average-sized American homes (and the amount of energy generated were the turbines to run under ideal conditions for 1000 hours.)"

EVEN if you take into extreme losses and minimum wind/hours, 85.5 MwH is only 8% of the theoretical, something seems amiss


Modern high-rise buildings consume up to 76 % of all Grid generated electricity. Any attempt to create building-integrated wind and PV needs to be explored. As the energy designer of the building, I can tell you that the building has provisions for PV on top of the building's shrouds which act to channel and accelerate the mass flow of wind through the roof of the building. An increase of just 3 mph in the wind (typical in this site) will double the output of the turbines. It has been shown that vertical axis rotors while less efficient than horizontal axis rotors do not have to track the wind leading to greater availability and no processional vibrations especially in the urban environment where there is more turbulence. Further technical details are available from reinhold@synergyii.com

Reinhold Ziegler
I think it is trick wording. The word is integral. These turbines do not sit on a roof but are integrated into the building as they are actually covered by a roof. Either way it is a good thing. Every little bit helps. Jim Sadler

But....do they work? Its unlikely they will produce any or enough power to make it at all worthwhile. It could be just another case of 'greenwash'. I'm not sceptical I'm a hardened renewable energy install of micro-power for 20 years. I want to see the actual generated output figures, 1. in real-time peak kW output, and 2. after one year's operation in kWhrs.

Paul Fletcher CEO www.e-si.com

re; Reinhold Ziegler

Treating and delivering water is the single largest use of electricity in the USA but but it is often done with onsite generation. Which leads to the question can they generate excess to need, and how difficult would it be to get it to the grid.


WELL WELL WELL..LOOKS LIKE YOU NAY SAYERS HAVE IT ALL FIGURED OUT...RIGHT...first of all lets look @ how much real wind it takes to get a Hor as a posed to a Vat started turning ...well we all no the answer to that one... now lets set a audible noise pollution machine up to the both of them.... ah well we all no what the results there are.... now just how many birds do the Vat kill... again we all no the results there..

THE ONE BIGGEST PROBLEM I SEE IS THAT YOU IDIOTS FORGOT COMPLETELY ABOUT MAGNETIC LEVITATION...if it is good enough for rail industry world wide it is damn sure good enough for the Wind Industry...

go look @ my 10mw model.... https://www.facebook.com/AdvancedTechnologyIndustriesInc

Solarman Jd

I think that you guys need a crash course in wind energy systems. Here are some answers to your questions.

Eric Malatji The Venger wind turbines featured in OMRF wind tower can also generate energy for off-grid purposes. The electrical energy would have to be stored in batteries.

jerryd Jerry, horizontal axis wind turbines HAWTs properly sited in a laminar flow of air are serious power producers. However, they will not work in the city or with turbulent winds. With turbulence the machine will spend half, if not most of its time, looking for the wind. When it finds the wind the wind will have changed direction. The answer for building integrated wind are vertical axis wind turbines VAWTs These machines can accept the wind from any direction, they do not require a tower and have a greater availability to harness energy from the wind.

Bob Stuart, From my years of having worked with the wind I now realize that the wind does not blow...it sucks! Once you realize this fact then you will be able to appreciate that the wind hitting these drag rotor turbines are going 3 to 5 miles/hour faster than the ambient wind. This increase in wind velocity doubles and triples the output of the turbines. The suction effect is caused by the ducted shrouds that make up the building. Also the rotors are shaped like DNA molecules which happen to be the logo of the Oklahoma Medical Research Foundation.

fmstark, Please let's do the math correctly. The project has 18 Venger wind turbines each rated at 4.5 Kw at 20.5 meters/second. This represents a maximum output for 18 turbines of 81 Kw. 20.5 meters/second is a high wind speed. In order to estimate the power output of one or all 18 turbines we have to know the wind speed spectrum or the number of hours per year that the wind blows at 5,6,7,8,9,10, etc meters/sec. Each wind speed has a different energy density (watts/sq meter). By multiplying through the wind speed spectrum (hours-at various wind speeds) by the watts produced by the machine at various wind speed...we get kilowatthours (Kwhrs) produced per year by the wind-turbines. I have calculations for the anticipated energy production by the turbines. We are now verifying those outputs with what is produced at the site. If you are interested Contact me reinhold@synergyii.com

Paul Fletcher As a designer of wind energy systems and wind farms since 1978 I, like you, are in this field for the long-term. I have no tolerance for bad design. Our field of work is called Solartecture. I have projects that have been in operation since the early 1980's. Our team has no need for green washing and no need for planned obsolescence. Check us out at www.synergyii.com. Provide me your email address and I will inform you of the performance of the Venger and other Urban Wind turbines that we are running.

Pikeman Thanks for you interest and enthusiasm. A good course in renewable energy systems with some hands-on would do you good.

Remember, all of you. "Those who take no chances...make no mistakes." "The alternative energies are now mainstream producers."

Reinhold Ziegler, Energy designer and Solartect.

Reinhold Ziegler

This is one of the worst designs and least effective, re COST PER KILOWATT, possible. Far better would be to have one LARGE vertical axis sail based turbine, the power of that would be FAR greater than this load of 'modern art', and would cost far less to manufacture and install too.

Post a Comment

Login with your Gizmag account:

Related Articles
Looking for something? Search our articles