Small, modular wind farms

small vertical-axis wind turbines

Professor John Dabiri and his team have been conducting research for over 8 years on the potential of small vertical-axis wind turbines (VAWTs) for wind farms. According to their data, by using the wind wakes that so drastically inflate the size of wind farms using horizontal-axis wind turbines (HAWTs) constructively, rather than destructively, a VAWT farm could produce the same amount of power in 1/10th the land area, using turbines that are around 1/8th as tall. This has huge potential for industrial power production, as Dabiri et al rightfully point out, but I see an equal potential in a smaller niche: energy independence.

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Photovoltaic solar panels (PVs) are currently the standard for community energy independence, from experimental ecovillages, to exploited areas such as Puerto Rico or Navajo Nation, to more privileged people looking to reduce their reliance on fossil fuels. This makes sense - even using the synergistic VAWT layout, solar still outperforms wind in power-per-area, assuming roughly equal reliability of wind and sun. PVs have a host of other problems, though, most notably a very high energy input, high cost, reliance on industrial production, and lots of intermittency from nighttime, clouds, and winter requiring large batteries. On the other hand, VAWTs can be built by the communities hoping to use them, potentially at very low cost in both energy and money, and run much more consistently through the night and the winter - potentially making up for the extra land area

While the synergistic VAWT layout is very efficient in terms of power-per-area, the one concern I have is power-per-turbine. A dynamo on each windmill could inflate the cost of the system quickly, and though smaller generators can be built from salvaged electric motors, the ideal turbine for this system is too large for any consumer washing machine or dryer motor and so finding enough motors could be tough. I believe the best solution to this would be mechanical transmission to a central generator, either through something like a jerker line or - my preferred idea - water pressure. Each turbine could run a mechanical pump, sending water through a series of pipes to run a single, large water wheel - which could either be salvaged from old industrial machinery or built by the community. This system could be incorporated into plumbing, welling, purification/desalination, etc. and could even be attached to a gravity battery system, pumping water upward when supply exceeds demand to be run back through the turbine when demand exceeds supply and thus solving the intermittency problem. A system like this would also be really easy to expand as needed
Of course, this kind of design isn’t a catch-all solution - nothing is. Areas with more reliable sunlight (such as tropical regions or deserts) and/or less reliable wind might benefit more from solar power, whereas communities with small enough energy demands to be provided by a single HAWT (like Open-Source Ecology’s design, for instance) wouldn’t have to deal with wakes at all, and thus could provide their power with only the space needed for its physical structure and access to the wind. I definitely think there are cases where synergistic VAWT clusters would be a great fit, though, and I hope this post inspires engineers, makers, and communities to start working on a robust, open-source design for such a system


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