Wind energy is a big business world-wide, with billions of dollars flowing around at various levels. And as in any large and growing market, a wide variety of people are attracted to it. Most are solid, competent professionals. Some are superstars. A slightly larger percentage than in other fields are engaged in part because it’s the right thing to do, not just something they can do well and make money.
Along with all of the professional people, there is a physically/economically optimal design that the vast majority of wind generators have converged to: the three-bladed, horizontal-axis wind turbine. This is the most efficient design due to pure physics: the blades are always flying in clean air, at the optimal angle to the wind, at the height of strong wind and have the added component of aerodynamic lift as another vector of force.
There are about 240,000 of them worldwide in sizes ranging from a few kilowatt capacity to 7 megawatt capacity both onshore and offshore, in rural and urban areas. Four out of five of the top selling small wind turbines are horizontal axis two- and three-blade wind turbines (only one 2-blade one, but it’s a reasonable choice at this scale.) They are generating all but a tiny fraction of a percentage of the electricity harvested from the wind in the world. They are undergoing constant incremental improvements in design including:
- Low-wind vs high-wind models
- Variable pitch blades
- Gearless vs geared nacelles
- Slight variants of blade design for aerodynamic efficiency
- Leading edge coatings
- Tower design
- Base design – rock-anchor vs concrete-base vs tethered floating vs. bottom-mounted offshore
As examples of the types of innovations that are constantly underway, yet aren’t particularly sexy, here are three recent stories. In the first, a duo at an aeronautical university realized that they had a design for a gearbox that would last longer than current gearboxes and are looking to put it into wind turbines. In the second, software-based predictive maintenance that has been used for years in other industries is being applied to wind farms to optimize maintenance schedules, purchases and hence costs. Both of these make gadget geeks and a lot of enthusiasts yawn, but there is enormous money in shaving a percent here or a percent there off of costs when the costs are in the billions. The third is more exciting to your average tech-head, but it’s still incremental supply chain innovation: a giant, specialized ship for installing offshore wind turbines that can transport and install eight to ten, 6 MW wind turbines in a single trip.
Sandia Labs, the pre-eminent wind generation test facility in the world, got out of the business of testing and developing vertical axis wind turbines (VAWTs) in the 1990’s due to their proven ineffectiveness compared to horizontal axis wind turbines. They are re-opening their historical research to see if some of the design characteristics of VAWTs might make them more suitable for offshore wind generation, where the different compromises might be economic, but it’s unlikely that VAWTs will capture more than a tiny fraction of the market compared to HAWTs even if they prove to be equivalent for offshore wind. Kickstarting a new technology and new supply chain for one niche when that niche is well served by existing technologies that also work on land is likely not optimal. This is a counter-example to the rest of the examples below; it’s thoughtful, it’s being done with full knowledge of prior art, it’s being done by a top notch organization with a long history in wind energy and it’s being done because they think that the compromises might favour VAWTs for a specific niche. It’s a stretch, but no one is spending big bucks on this yet, just enough money to dust off the research and think through applicability to the niche.
There are, of course, people who don’t fit into the wind industry categories in one way or another. Perhaps they aren’t particularly intelligent or competent. Perhaps they aren’t professional enough to carefully assess prior art to see if their great idea has actually been fully assessed and declared unworkable 15 times before. Or perhaps they just see the opportunity to make a fast buck off of people who think that a disruptive new wind generation technology will be worth a lot of money. A subset of these people come forward with ‘innovative’ and ‘new’ wind energy technologies which they claim solve the mostly non-existent problems associated with the current leading technology.There are a few dozen designs in play at any given time, which have perhaps tens of thousands of instances with very small generating capacities world wide. These include variations of savonius windmills, darrieus wind turbines and a variety of flying or compressing designs. Almost none of them are producing electricity right now anywhere in the world at anywhere near utility scale; most of the ones that are producing any electricity are for off-grid applications such as sailboats or local-residence supplemental electricity (both of which are very well served by small scale horizontal axis wind turbines or HAWTs).
As a thought exercise, look at the picture of a simple savonius windmill below and guess reasons why it’s never going to be as efficient as a horizontal axis wind turbine.
Yet one ‘inventor’ created a version of this that used injection molded fiberglass with dimples for aerodynamics on the leading concave edge, magnetic levitation and a handful of other ‘improvements’ that merely resulted in it being a very expensive ineffective generator of electricity. He even claimed that wind would somehow fill the inside of the hollow structure generating additional force. And he was actively peddling this intellectual capital for sale. The only good thing about this situation was the business niche that was being targeted: charging backup batteries for remote communication towers using low-maintenance renewables instead of diesel generators. This is a design point and market that could be worked toward using existing solar and wind generators, and there might be a nice small business in there.
A higher profile ‘innovation’ is Saphon, which actually got a TED spot for something that is so obviously deficient that any one remotely related to the wind industry would have laughed it off the stage. Professionals’ comments regarding it are invariably brutal.
Its failures include inability to scale due to mass of the conical device they use, no ability to feather the cone so it will likely fall over in high winds and a mechanical piston actuator that also won’t scale and introduces massive inefficiencies. The patent it claims represents its breakthrough is actually for a different device than the one they are promoting. They explicitly call out many of the myths denigrating wind generation as real in their promotional video and then claim their design solves these almost non-existent problems. The two principals have no background in wind energy, but one is a former investment banker who specialized in getting people to invest money in companies. Is there a niche where their product is better than a tri-blade HAWT? It’s extremely unlikely in our physical universe, yet this doesn’t stop them from seeking new investors, creating prototypes and getting a remarkable amount of fawning press including being shortlisted for an African innovation award recently. The principals are much better at PR than engineering.
An idea what won’t stay buried is shrouded or cowled wind turbines, where a bulky external shroud concentrates air flow on a smaller wind turbine. This idea is challenged in ways similar to the Saphon, in that scaling up typically produces a massively heavy and shear susceptible bulk on top of a tall, relatively slender pole. Effective harvesting of wind requires getting the generator up into the air where the wind is stronger and having a broader surface area to harvest from. All the shrouding does is reduce efficiency of a three-blade HAWT with the same diameter and much less material than the shroud. Yet this is re-invented with prototypes being funded regularly, as if no one in the history of wind energy has ever in the past thought to apply the Venturi effect to wind generation.
High-altitude wind is another area with a lot of funding spent on research and development and no production generation of electricity. Some products such as Makani put solid and relatively heavy wings with blades and generators at the end of long tethers / transmission cords (for my full assessment of Makani, please see this: Google’s Makani airborne wind generator flies a bit lower when you look at it closely). Other such as Kite Gen Research put all of the hardware on the ground and use a relatively simple and much safer parafoil kite to haul line out in the power zone, and reel it back in out of the power zone. Others use blimps with either blimp-shrouded turbines or variants of airborne savonious turbines. They all promise to tap into the greater potential energy of wind at higher altitudes. There are any reasons why these technologies haven’t taken flight in the market. The complexity of launching, controlling and retrieving a flying object autonomously is enormously more difficult and has a much higher likelihood of failure than just building a taller, stronger mast that doesn’t move. Modern, utility-scale wind turbines are already in higher and steadier wind altitudes, so differential gains aren’t as great. These designs require unobstructed downwind ranges that are quite long. They fly higher and have longer tethers, effectively creating a much larger and potentially varying no fly zone than fixed position, tower-mounted wind turbines. Especially for the solid flying wings, the potential liability in case of failure is much harder to certify and insure, greatly increasing the cost of business. Once again, there’s a small niche for some of these in very remote sites with temporary facilities where the downsides don’t matter and the ability to pack them into small spaces has strong advantages. There is a business model, but it’s not a mass market one.
Many of these innovations claim to have found a way to exceed Betz’ Limit of 59.3% of potential energy harvested from a volume of wind. None have stood the test of third-party, independent testing. Some claim that Betz’ Limit doesn’t apply to VAWT technology and then point to Sandia Labs documentation which clearly says that it does. Virtually none have performed ISO standard full lifecycle cost assessments, published them and had them audited by independent third parties.
Most claim to be quieter, although virtually none publish side-by-side noise evaluation tests with similarly scaled HAWTs to prove it. Many claim to kill no birds, although there is no proof of that claim either (and of course utility scale wind generation is the best form of generation for birds from a species perspective.) Some anti-wind lobbyists have internalized these claims without understanding them and actively promote the idea that there is a better alternative for their pet concerns.
Then there are the situations where there doesn’t even appear to be a physical product of any sort. A firm in the western US received $4 million up front a handful of years ago from the municipality to build a factory for savonius-style wind turbines. It has delayed breaking ground on its factory for four years, doesn’t have a working website and is saying delays are due to bird tests (not true according to the agency that was performing them), a completely unrelated scandal many states away and the need for more money in the bank. It appears to be nothing more than a large scale scam that has already netted them around $4 million and they are hoping to get $10-11 million more. All for a conceptual variant on that barrel split in two above.
There are minor niches where alternatives to tri-blade horizontal axis wind turbines are effective. There is a vertical axis design, for example, that self-stalls in high-winds, making it effective for remote locations with regular very high winds, e.g. Antarctica. There are a few darrieus variants that are remarkably attractive kinetic sculptures that happen to generate electricity as well, where the aesthetic value makes the high cost per KWh palatable. Some of the blimp-based design are good for remote locations.
So, how can you inoculate yourself against putting money into a bad wind energy product? Ask these simple questions and if any of the answers are Yes, be suspicious:
Technology Red Flags
- Do they claim to exceed Betz’ Limit?
- Is it an old technology claiming to be a new technology?
- Is their product just a design concept as opposed to at least a working and tested prototype?
- Are the only test results from tests that they have performed as opposed to independent, third-party labs, and do they expose the numbers?
- Are claimed patents for devices other than the one they are demonstrating?
- Are they claiming greater efficiency than existing generation technologies based on anything other than an ISO standard full lifecycle accounting that has been independently assessed?
- Are they claiming to integrate storage into their wind generation device without a market niche need?
Business Model Red Flags
- Do the principals have backgrounds entirely in fields unrelated to wind energy?
- Are they starting from a product as opposed to a specific and tightly targeted market niche?
- Are they claiming that their product will replace utility-scale three-blade wind turbines?
- Does the product introduce major new liabilities e.g. downwind throw of solid flying wind turbines and cable, or varying flight obstructions?
- Do they disparage other wind generation technologies to establish their technology’s superiority?
- Do they have a web-site that is just a facade or is missing entirely?
For a rating of currently active wind technologies, have a look at the companion post to this one, Good and bad bets: new wind technologies rated.
The wind industry is disruptive because it is supplanting fossil fuel generation at a reasonable cost. That reasonable cost is due to decades of incremental innovation and major supply chain and business innovations, not radical technical innovations. The most effective technology was chosen a few decades ago, and it’s been getting steadily better ever since.
The wind industry isn’t going to be disrupted by someone with an idea and a Powerpoint pitch. If someone is approaching you with a great investment opportunity based on a ‘new’ wind generation technology, be aware.
A short version of this post has been published on Gizmag.com at http://www.gizmag.com/dodgy-wind-turbines/27876/. The fee for the published piece was donated to 350.org, which is devoted to building a strong global climate movement.