Ropatec, A modern VAWT for IPPs

Over the years we have followed Ropatec financial and company ups and downs. It’s good to see Ropatec have transitioned their design to one with better tip turbulence management (nifty tip spoilers), together with  lower cost tower and  lower foundation capex costs. We think Ropatec have finally found a niche in the “Fill-in” under-performing Big Wind market. (There are many). Operating in the 15-25m  semi-turbulent wind band , Ropatec is connecting their newish 30kW Nameplate Gyromill VAWT into existing EU located Big Wind Farms and their  local electrical generation connection  systemto help boost under performing IPP Big Wind Returns.

Mini-VAWT Wind Farms (will) RULE! Read on if your an IPP … 🙂

Modern VAWT Lessons for the IPP interested in  add-on Mini-Wind Farms

def.- IPP: “Independent Power Producer”.

Ropatec it can be argued, was the very first VAWT vendor, even before now defunct Flowind, the latter which had greater early commercial success in 1984 (over 800+ Turbines installed in North and South California for PG&E and So. Cal. Edison respectively). That said, some of us old enough to remember  and witness Flowind succumbing to bankruptcy in 1997,  due largely to earlier Gen I reliability  failures caused by aerodynamic design flaws and also helped by the Bush IS government administration removal of the Federal Wind Tax credit in 1996, where  after much progress with the NREL, and the DoE, the more than capable and very promising Flowind Gen II design never made it to production. (only two Gen II test examples ever operated @ 330kW nameplate in Tehachapi Pass, North CA.)


Circa 1993 A ground stay tethered Flowind 55m tall 330kW Gen II in foreground  with a few of the over 800 Gen I 30m tall 110kW turbines installed back in 1984 spinning in low mount wind in the  background.


Here is a nice video of Ropatec’s Tuscany installation showing the  seven installed  30kW VAWTS, properly sited producing quite nicely. Installed in 2012, so reasonably recent. Also the entire installation process is shown.

The only question in our mind is,  after viewing this video? Ropatec,  for a wind turbine of this size @ 30kW NP, how expensive is the installation?  What we noticed is there was a temporary stand used for assembly, then cranes on site for lifting, and several staff which seemed excessive  and overkill given the turbine rating. Also the use of a concrete foundation is questionable today when we know modern structures much bigger have employed soft ground or hard rock screw piles to achieve the same and even better foundation capabilities.

What is certain about the Ropatec installation in Tuscany (circa 2012) is that our perceived extra installation cost has a negative effect on the LCOE “Levelized Cost of Energy” calculation, pushing out the BE “Break-Even” for the IPP “Independent Power Producer” employing these next generation “Gyromill” 3 blade designs to reduce the overall ROI for the Mini-Wind farm project.

What is definitely good about Mini-Wind Farms is their ability to leverage the existing Big Wind  feeder electricity grid “Behind the Fence” to boost overall Big Wind farm efficiencies back up to what was originally promised by Big Wind vendors  as is rarely met over the life of the farm, that is the promised annualized output based on a percentage of the wind turbine’s rated “Nameplate” power output. A Mini Wind Farm like Ropatec’s can recover the profitability of most Big Wind Farms, boosting their  overall % of nameplate rating (as recorded by the regulatory body measuring output from what is typically as low as 22% to averages 26% in most jurisdictions) up an additional 2-4%  (depending on number of mini wind turbines deployed) which can make all the difference in the world over a 15 year Power Purchase Agreement using CAGR formulas to figure out the PPA return:

For a US $1M investment over 15 years, investors would like to see a steady 10% annualized return for money spent, which means the asset employed (invested in) like the Mini Wind Farm in Tuscany, needs to generate   US  $5M to generate an 11.93% annual return on the money invested.

Try the CAGR calculator here to check our numbers.. 🙂

CAGR Calculator

This means  based on the Ropatec annualized quoted output for the 30kW VAWT at 7m/s average annualized wind speed producing 750kW hours of power the IPP can expect annualized output over a 15 year period  of 8.5kW/hr power output meaning 8.5kW/30kW is 28.53% of nameplate, which is a reasonable promise to make.

Looking at Italy’s Feed-In-Tarrif:  (courtesy of

GSE Suspension of FIT payouts for Non Compliant 6kW and 50KW Power generation Sites

GSE issues a press release on the suspension of feed-in-tariff disbursement for lack of conformity to Annex A.70 of the Grid Code

Pursuant to Resolution no. 84/2012/R/EEL of Italian Regulatory Authority for Electricity, Gas and Water (AEEGSI), as subsequently amended by Resolution no. 243/2013/R/EEL, GSE is suspending the disbursement of feed-in-tariffs, as well as the effectiveness of simplified purchase and resale arrangements and net metering arrangements, to owners of plants which are not compliant with the rules of Annex A.70 of the electricity grid Code. GSE will communicate the decision to suspend incentives by email to each operator affected by such decision.

Our analysis shows the GSE pays out the following rates for the Ropatec Project which overall is  nameplate rated at 7 turbines * 30kW or 210kW total nameplate (the peak GSE can expect on very windy days over 15 m/s with this type of Gyromill Design) and with 28.5% of nameplate quoted by Ropatec for the 30kW design deployed at this site based on annualized 7 m/s wind speed ( see article , the IPP can expect to generate annually at this Tuscany site:

8.5kW/hr * 365 days * 24 hours =  74,600Watts * 7 Turbines = 521,220 Whrs   annually


GSE current FIT rate for this type of  of <300kW Nameplate project is per turbine <50kW:

0.268 €/kWh which is roughly .27 cents US $  for each kW hour produced.

Assuming the Italian government keeps the rates where they are, a 15 year FIT supply deal  via the IPP as above from Ropatec  is estimated by us to Cost US $630K (7 turbines of 30,000W @3.00/Watt installed or  US $ 90,000/turbine, total cost of US 630,000)   for the IPP would yield in FIT revenue:

15 years * 12 Months * 365 days *24 * 8.5kW/hr * IT FIT of .27 cents  US$ = 3,618,756 *7 turbines

or US $25,331,292M in value generated from the Italy Fit for the entire project.

Let’s now look at the cost of maintenance over the 15 year period. Typically vendors like Ropatec or any NG (Natural Gas) micro gas Turbine vendor like Solar NG fired Electricity Generation Turbines (weird green-washing name if there ever was one)  will quote an O&M price per watt, in the range of US $6.00 to 8.00 for a 15 year period, where the variables will be  servicedepot location(spares) vs. site, local labor costs, and time to site costs, as well as Turbine access and repair logistics, and weather (time of year).This is where the real vendor money is made, so getting a low capex price from the vendor, does not necessarily mean the IPP received a “good deal”.

Let’s give Ropatec the benefit of the doubt and use US $6.00/Watt Regular O&M costs (inside warranty with any routine parts replacement and maintenance provided by the vendor, exceptional “Ac of God” maintenance, is the responsibility of the IPP or paid by the IPP to the vendor in a la carte quote fashion.) Let’s use a single turbine to keep in simple:

Nameplate of 30,000 Watts rated output (11 m/s) * Us $6.00/Watt = US $ 180,000

So for a  US $90,000  CAPEX Investment +  US $180K 15yr O&M Opex = Us $ 270,000

Revisiting Compound Annual Growth Rate CAGR, we can see that the IPP  generates per Ropatec turbine US $ 3,618,756 over 15 years which means a CAGR of the IPP’s investment of

CAGR  18.89% on the Ropatec Power Mini-Wind Farm in Tuscany Italy- Wow.

Great!  (especially when negative interest rates are in play everywhere, so cost of borrowing is cheap and this is a bankable project in any banker’s book).

In general, however when the Ropatec Mini-Wind farm is compared to competing power generation from natural gas where the CAPEX installed cost of similar NP generation would be @  US $2.00/watt (our field experience)  it becomes a challenge to figure out which place to invest your money as an IPP, given swings in NG fuel prices and  government regime changes to FIT regulations, their favorite toy of late, virtually everywhere.

In reality, Ropatec will hope that the reliability of the  new modern Ropatec 30kW turbines and the actual maintenance, repair and warranty replacement and regular scheduled parts replacement, will cost less than what was contracted with the IPP, and that other cost improvements will be achieved from the new sales and service parts of the vendor business, namely more Mini-Wind farms  sold and deployed, lower cost future designs with better margins (there is room for improvement here, always) etc.. Finally the vendor “bean counter” accountant types will get to work and hedge currencies with surplus working capital earned from these farms, play metal markets etc, to squeeze every last drop out of the 15 year project to ensure a decent shareholder return and private dividend payout with least tax exposure. Hurrah!

The  Micro NG Turbine Challenge to Mini-Wind: maybe , sort of, not often.

Of course Natural Gas local distribution pipelines may not be readily available for tapping into the site where the grid tie is allowed (plus sound ordinances in local bylaws may prohibit the location of what are fairly noisy gas turbines with tall mufflers and ground level ozone emissions kill) , so in this case Mini-Wind should win every time, and low mount VAWTs like Ropatec stand as good a chance as any, especially versus small HAWTs in the same nameplate rating which must be installed 50% higher with larger install and overall capex costs, and are less visually appealing.

Small HAWTs vs Small VaWTS?:  

Modern VAWTs win every time… if nameplate is same.

It’s the Lower Height and Power Output/Acre….  🙂

Ropatec, like all modern small VAWTS have the advantage over small HAWTS in that a properly sited and turbine spaced modern VAWT Mini-Wind Farm can produce 25% to 50% more power  conservatively in a 3X smaller physical footprint  at a 25-33% lower mount height,  because VAWTS do not need as much real-estate to operate and can survive semi-turbulent wind.

The lower mount height and greater power density/per acre mean the VAWT Mini-Wind farm can have a 75% to 1505 LOCE advantage over Small HAWTS, every time, provided the HAWTS with their 3X bigger spacing requirements can get a series of suitable land leased in place to compete at a reasonable price through multiple landlords

So even though the competing 30kW nameplate HAWTs might be 15% more efficient at 7m/s using a 33% of NP for HAWT vs a 28.5%  of NP for VAWT comparison in nameplate efficiency as claimed by leading Vendor Bergey over Ropatec, the HAWT single turbine efficiency is not enough to make up the VAWT advantage of greater power output density per acre. Let’s look at this modern VAWT supremacy a bit closer:

For Example, imagine a 7*30kW nameplate (@7m/s) turbine HAWT mini-wind farm with 33% vendor claimed nameplate efficiency,  installed at the same Tuscany, Italy location where Ropatec is deployed, the annual total kwhr output would be:

at 30kW Small HAWT design will produce 10kw/hour @ 33% efficiency * in 7/ms annualized wind speeds,  but needs 17 to 22 HAWT rotor diameters spacing and straight wind at 35% higher height to perform to 33% of NP, the HAWT vendor claimed advantage.

So each turbine will effectively need its own leased footprint, 7 of them,   versus the VAWT mini Wind Farm which can fit within one small leased space which is in fact only 20% of the real “spaced area” sq. m area needed by the HAWTs. How to calculated the annual lease rate comparison can be challenging, but let’s give it a go.

HAWT Sweep area @ 30KW is 5.5m Blade Length, 11m top to bottom = 95 sqm

Let’s use the HAWT tighest spacing, 12 diameters, Wooha! 110m spacing, essentially a football field at 30m tower height, that means talking to lots of landlords, but also laying lots of extra cable to tie in to the existing Big Wind Farm collection and concentration cabling feeding the grid tie need to take advantage of the FIT.

Ok we space equal distances and basically get  a 1/4 mile by 1/4 grid in the country (16 American football fields), being flat or with very little roll, and the tree canopy of equal 30m height need to be at least 200m  away from the nearest HAWT turbines. So expect to talk to 5 or 6 land owners in the country to get this type of  land lease deployment. So called  research costs and pure Overhead are sure to be reducing LCOE for the site and often delaying time to market for any Small HAWT Mini-Wind Farm deployment.

See the REAL problem for Small VAWT Vendors? the number of  raw addressable available sites for small HAWTS at 30kW at 30m height start to be reduced dramatically (by at least 10X) in contrast to modern VAWT deployments of the same 7  Ropatec or Starwind5   VAWTs and your spacing is 40 to 50m apart and fits in 4 football fields comfortably.

Small VAWTs rule  while small HAWTs drool (with great jealousy). Now the kicker, if you use clockwise and counterclockwise mated pairs of VAWTS the spacing is only 2 to 2.5 diameters, meaning 22m to 30m, and that means you need only 1 American football field for these 7 VAWT turbines, meaning a single farmer lease will do it siting the 7 turbines 3 and 4 each down each fence line (typical in North America) and just two simple trenches to run the collector cables, in either spider(smaller cables parallel in trench) or tap(grid style with electronics and connectors to one big cable) and daisy chain form.

Let’s revisit a FIT Style PPA in Italy for you IPPs out there considering Mini-Wind Farms:

a PPA of 15 years * 12 Months * 365 days *24hrs *10kw/hour with FIT of US $ 0.27 =

yields US $ 4,257,360  per HAWT 30kW Nameplate turbine  as above..


US $ 3,618,756 for the Ropatec VAWT at the same site.

Difference?  US $638,604 in favour of HAWTs

NB- HAWT margins are thinner due to higher install, tower and foundation costs, they have no room to move, where as the VAWT vendor can move somewhat with 10-15% better turbine sales margins.

So on paper it appears the advantage goes to the HAWT 1 on 1 for pure Revenue generation

Now let’s look at the CAPEX and OPEX side of the overall LCOE equation:

Consider the installed price is the same, CAPEX  US $ 90,000 for either HAWT or VAWT

and that O&M per turbine Costs are the same $6.00/W

OK, so it comes down to these Differences due to Turbine Spacing needs for vendors to maintain quoted NP efficiency percentages to the IPP:

HAWT                      VAWT

One Time Trenching costs                                                          4X higher                —-

One Time Collector Cable Installation and Activation      4X higher               —–

Cost of Cable                                                                                  4X higher               ——

Turbine Hook-up Costs                                                               20% higher         ______

Annual Land Lease Costs                                                           2X higher              ——-

Visual Appeal Preferrence                 (PG&E report 1984)   ——-                 4out of 5

NIMBY  Total Height Visual Complaints                              36m                         25m

The real question for the IPP to be answers is this:

Do the VAWT Savings above equal or exceed the Difference?

US $638,604 in favour of HAWTs?

And the Short answer is? YES!!!!

US $638,604/ 7 Turbines   =  US $ 91,229.15 per turbine

Mini-Wind  Farm Land Leasing- Generally Land   Leasing per Turbine will be not more than Us $1000.00/Turbine year  =US $7,000/yr for HAWT single plots peppered across the country side versus VAWTs at $3600.00 or just over US $500.00 (150.00/mth per fence line as rent or a credit off monthly farm power consumption for siting all 7 VAWTs)

HAWTs Land Lease -15 years, 7 plots , different landlords   US $105,000

VAWTs Land Lease- 15 years, 2 fence lines, 1 Landlord        US $43,200

Advantage VAWTs US $ 61,800.00  (10% of the way there, or so)

Real HAWT CAGR adjusted to US $345000 CAPEX for 1st time install =

CAGR 18.24% and only if the HAWT vendor delivers 33% of Nameplate which is rarely seen in small wind deployments.

Mini-Wind Farm One Time Trenching, Collector Cable Material Install Costs- This is the big one, which will vary by country depending on trenching operator  and equipment charges,  what is clear is Western World, Japan charges will be at least  US $150.00 for 1 man/trenching, and soil composition will determined how fast it gets done to lower the cost. If you are mounted on Rock there is no choice but to go aerial and your costs will 2X to create new “Squirrel Highways” and Bird Perches. 🙂

Let’s assume the most optimal daisy chain and tap path for HAWT grid of 7 turbines, this means at least 3200m of linear trenching, 1.2m below the surface in colder climates to get below the frost line , maybe less in subtropical and tropical climates. This is one mile a of cable, which is 10560 feet @ US $5.00/ft = US $ 53,000 just for the cable.

Anyway you shake it it a 4 week job to trench (if you can get the right way) at 160 hours for the operator and equipment at US $ 150.oo/hour (this is a great rate by the way) = US $24,000. To lay the cable  and fill in the trench, same  US$24,000.  Are we there yet? Yes, we have now racked up a US $101,000 bill for HAWTs Non-recurring Cable install Costs, and we haven’t even paid the Electrician to hook up, test, and activate, as well as provide all the electrical coupling and electronic collector tie (grid controller gear for non transduction Permanent magnet generator drive turbines, which is the case in this small wind size). Add  US $21,000 for 7 turbine tie in, we are now up to US $122,000.

OK given VAWTS are 4X cheaper for Trenching, Cable and Cable burying, and bit cheaper 20% for Hookup (Electrician does not have to go so far between turbines) what is the difference:

Cabling Costs Total  US $101,000 for HAWTS /4 times less for VAWTs = US $25,250

Cabling Difference = $75,000

Land Lease  Difference = US $ 61,800.00

Cabling and Land Lease CAPEX VAWT Advantage                           = US $ 136,800.00

Less HAWT total power output  Advantage                                         – US $ 61,800.00

Total VAWT Advantage with Unit price parity  over HAWTs        = US $75,000.00 


IPP Turbine Price Comparisons in Cost/W: What is the True Story?

Now let’s revisit for the IPP the CAPEX cost side of the equation to understand a bit better how vendors quote small wind, here is our best engineering guess factoring wind loads on the turbines to determine cost of towers and foundations at different heights, land area mount and lease costs given difference in  spacing requirements, and installation costs, all represented as percentages of Nameplate Capex Cost (total installed cost).

N.B.- Keep in mind US $ 3.00/Watt installed is very aggressive pricing  direct from the Vendor,  meaning there is no room for the IPP to order through a local distributor and maintainer, and .50 to .75 cents to the Turbine Capex Cost if you must use the locals due to recurring maintenance. Where the vendor is not “in country”, expect to pay more.

   HAWT                     Ropatec

Tower Height                      30m                             20m

Tower Costs                       35% of NP                    25% of NP

Foundation Cost              15% of NP                      10% of NP

Installation Costs             5%  of NP                     7.5% of NP

NP installed Cost              90,000                          90,000      (Cost/W 3.00 for both)

NP Turbine Price        US $ 41,500              US $ 51,750

Turbine Cost/W           US$ 1.65                  US $  1.72   <—– This is what Vendors quote

So even though the VAWT Turbine Cost/W is higher due to the employment of more materials  and labour to build  the VAWT vs the HAWT, the vendors match each others installed price. Now at this turbine price stalemate point is where it gets really interesting for the experienced IPP, and that is power output density or yield per/acre.

Same rotating VAWTS need 5-5 horizontal rotating diameters depending on high versus low average site wind speeds to perform close or at their rated effciencies in flat areas. VAWTS, as you can also see from the video can handle wind sheer better than VWATs that is the wind angle of attack coming up the hill actually helps lift the VAWT blades off the bearing to reduce bearing load and wear, hmmm, very interesting.

In contrast such wind angle of attack  (up a hill) will cause tremendous stress to a HAWT and generate  high amplitude flutter , that is the HAWT blades wagging back and forth like three dogs’ tails on the same dog, which stresses both the tower and the spinning hub bearing and the directional gantry bearing, means in reality, the HAWT must use a higher tower height to find straight win and make sure the OPEX  O&M Cost/W offered the IPP will provide decent vendor margins over the life of the 15 year PPA.

Advantage modern VAWT every time. 

A Mini-Wind Farm vs Natural Gas Turbine? Which one is best?

On the surface it seems Mini-Wind generation should win vs. Mini-NG powered generation over a 15 year PPA,  starting today given the forecast price of Natural Gas, and the enforcement of Carbon Tax on non-renewable energy powered generation.

However, investors  and IPPs need to pay attention to the politics of the Left, Centre and Right in their own country, state or province, as the current regime tendencies will swing investment money either way. A chage in government regime can mean a change(reduction) in FIT as it is clearly shown  in Italy with new  changes to existing regulatory enforcement causing break-even points to be pushed out even further negatively impacting CAGR as LOCE rises and ROI falls.

In the case of Italy and Ropatec, for now the FIT rate is locked in. Maybe the small print allows a government loop hole to further reduce the rate, maybe not.

Overall though, Ropatec should be applauded for doing it right, making the IPP  and their investors happy, a positively impacting the returns of the existing Big Wind Farm managed by that IPP to return the old farm back to profitability.

MW Batteries are coming:  IPP Mini-Wind Farms

both Lithium and Zinc Air, and will change the Mini-Wind farm opportunity for IPPs over night, here is how:

In the future, as battery prices continue to drop with increases in physical power density rising, Mini-Wind farms LCOE will be lowered, that is impacted positively and more rapidly help the return to profitability of Big Wind in un-regulated markets or time of day regulated markets where rates swing widely for power purchases by the grid from the IPP, and where time of day will challenge the battery engineering  of new wind and solar installations to maximize LCOE  dynamically so as to guarantee the IPP a decent return over their 15 year PPA arrangement to supply the power grid.

Where it gets really interesting for the IPP  in the future who is building Mini-Wind, Solar or Hybrid Farms, especially in these open or time regulated markets, is to sell power “Behind the Fence” in private re-sale secondary PPA agreements and as well partially offset the CAPEX and OPEX costs of Mini-Wind and Solar Farms with free land leases in exchange for lower power rates given to the land lord leasing the premises at lower than market costs,  a situation where additional returns can also be found by the IPP if they play their cards right in a WIN/WIN/WIN fashion.

MW Batteries will make all the difference in the world, and mixed with Solar will really see a mix of 30-50kW small wind Mini-Wind farms mixed in with 250W-500KW Solar farms, which will mean we could see a near extinction even in  300kW-800kW sized turbines which need to operate in 45 to 65m height wind flows with big spacing.

The Now: IPP Hybrid Wind/Solar and 1MW Battery Storage

“Farm Fence Line Mini-Wind power connected to Small Solar farms and MW Battery beside Cell towers makes perfect sense. So Why aren’t mobile providers jumping on this to get completely off grid and to also completely avoid Carbon Tax?” Good Question  we ask ourselves and interested parties all the time, I guess time will tell, for sure the way forward for IPPs has:

IPPs generating and storing power to deliver as needed behind the fence with timely sale of surplus to the gird from MW Batteries will be the order of the day and Small modern VAWT Mini-Wind farms together with Solar and Batteries will INDEED rule the roost.


Italy FIT market references below

Italy Small Wind FIT rates as of 2015 No Change

GSE: Italy to Maintain FIT for Small Wind Turbines

June 18, 2014,  

The tariff for small wind between 20 and 200kW for all the connected turbines in 2014 and 2015 will remain 0.268 €/kWh

This does not seem alot, however when you take in the existing  Mid Sized Windsite in can make a big difference to the IPP CAGR,  there are a few 300kW nameplate mid size turbines  deployed that are old, and under performing (probably 22-24% of nameplate, operating at a 60m Nacelle height (versus 30m for Ropatec tip height)  and sweeping with 35 meter blade to a visible 95m height. (Which is the case at this Tuscany location).