Double Production For Many New Wind Farms

There is a new shape of wind energy, due to the technological breakthrough enabling power density benefits for larger scale wind farms. It means that we re-think Vertical Axis Wind Turbines and their relationship to capturing more of the Optimal Power Potential (OPP) of a given piece of high wind real estate.

Power Density: HAWT/VAWT

As in other fields of today’s world, technology is opening doors to new renewable energy sources….and there is a ready market for what may seem like an audacious claim:  using Vertical Axis Wind Turbine arrays, that are MORE efficient the MORE CLOSELY THEY ARE SPACED, we can harvest 2x as much energy from a  high-wind site.  Too good to be true?

Power density requires that we start with a different question.

What is the maximum wind energy that can be captured from this piece of land?


WHI Vertical Axis Wind Turbine Systems (WHI VAWT Systems) build on one of VAWT’s main characteristics:  they can be spaced very closely together (2m apart) and in rows 50-100m apart to populate and capture the energy from “the field.”  Today’s wind industry gives up most of the field’s energy in its focus on turbine efficiency.

WHI Turbine Overhead View

Power Density also invites the idea that in large existing wind farms, more power density is possible, within the constraints of existing substation and transmission infrastructure.  In those cases, Power Density takes the shape of capacity factor enhancement. Throughout the world, there are many sites with 6.5 m/sec near-ground wind, and these sites are likely to offer developers new options:  capitalizing on “the field” rather than a few tall turbines, WHI turbine arrays are not only able to produce more energy/per acre but when set in counter-rotating arrays, they capture the “coupled vortex effect” where shed vortices enhance the productivity of adjacent turbines.

The principle is something like fish schooling or flocks of geese.  Learn more about the technology.

WHI’s patented turbine and placement patents reflect inventor Bob Thomas’ recognition of these effects and how WHI VAWT Systems capture their benefits.


Optimize New Infrastructure Investment to Capture “Optimal Power Production”

With Full Build of VAWTS

In the early 1980s, in California, WHI co-founder Bob Thomas was head of California’s Wind Energy programs.  Engineering firms and developers were eager to rush to capture market share.  He observed that the focus was on turbine designs that sought to capture the less turbulent, wind higher off the earth’s surface.  He recognized that what we see today as “the shape of wind” bypassed an alternate way of thinking and technology that was more complex, yet had the advantage of radically raising the “Optimal Power Production”(TM) from the fundamental resource:  high wind real estate.  This observation has been validated by California Institute of Technology:  Professor John Dabiri.

What Bob Thomas witnessed and understood, as an aeronautical engineer, was that the closer you place turbines with a vertical axis, the more efficient they would likely be, whereas the taller horizontal axis turbines created turbulence rather than more energy, the more closely they were spaced.

As with any field, continuous improvement tends to yield incremental changes over time.  In wind energy, conventional HAWT wind farms look very much like the early 1980s, some larger but generally using the same design.  “If something isn’t broken, don’t fix it,” is an old saying.  Yet Wind Harvest International(WHI) is bringing a new paradigm by starting not at how efficient the turbine is but by asking a different question:  “What is the optimal energy possible that can be recovered from a given piece of land?”  John Dabiri’s research indicates that theoretical limit for wind energy at a 7m/sec annual average wind speed, is 68 Watts/square meter.  Today’s state-of-the-art HAWTs are recovering 2.5 Watts/square meter.  Compare 68 to 2.5 and you will see that there is room for more than incremental improvement.

Many of the world’s high wind sites have been developed and WHI VAWT Systems can augment their capacity factor.  However, there are many premium sites where new large wind farms are being considered.  Imagine that we focus on the field of energy, rather than a picture of a few 130m high turbines spaced far apart.  In a 100 hectare plot, six 2.3 Siemens HAWTs are able to be placed. This will yield 13.8MW from that field.  However, if the field were filled out solely with a WHI VAWT System, the “Optimal Power Production” can rise to between 27.6 – 55.2MW, yielding more energy for the developer, for the land owner if the lease is based on gross revenue, and more for the global supply of renewable energy.

In the layout and design of the wind farm, additional substation and transmission capacity would be needed, yet it is already in a permit process and can be part of the original planning.  Integrating the energy from the many WHI VAWTs will add a modest cost, yet if the energy coming off this 100 hectare plot is 2-4x what was expected, it will not be a major detractor.

With a paradigm shift that calls into question our assumption that there is just one shape of wind energy, WHI VAWT Systems are prepared to offer a new shape, one that is modular and diversified to meet the global challenge for more renewable energy, today.