Mid-Size Turbines a Have Big Advantage in Output Relative to Visual Impact
No, that’s not mere click bait. That’s the argument Geoff Henderson makes in a provocative paper on wind turbine size and the landscape impact of wind turbines.
Henderson is founder and managing director of WindFlow, a manufacturer of a mid-size wind turbine in New Zealand. Yes, New Zealand. Most people in the wind industry wouldn’t know that he and his two-blade wind turbine even exist. But exist he does and he doggedly continues to promote his product despite overwhelming obstacles.
Henderson knows wind energy and can usually be counted on to make a solid case. I was reminded of this when I reluctantly agreed to read his short paper arguing why medium-size wind turbines—such as he manufactures--are easier to integrate into the landscape than multimegawatt machines.
His argument boils down to an observation brought to my attention decades ago by Paul White, then an intern and now himself a longtime veteran in the wind industry. White pointed out that the land area required for a wind turbine is the same regardless of the turbine’s size. Because of the spacing required between turbines, the bigger a wind turbine, the more land area required so the land area per MW or kWh remains relatively the same. White made a spreadsheet for me that showed how this works and I still use it today. I won’t elaborate on this point further; you can read Henderson’s paper where he explains this.
Elsewhere I’ve argued that bigger turbines only offer spacing advantages, relative to smaller turbines, where you can only install one or two turbines. Thus, a German farmer who is permitted to install only one wind turbine will opt for the largest he can to maximize his revenue. However, in an array of multiple machines, bigger doesn’t mean more optimum use of the land.
Henderson goes on to point out that bigger turbines, because they are taller, are visually more obtrusive than smaller machines. Again, he makes his case better than I can.
See Mid-Size Turbines a Have Big Advantage in Output Relative to Visual Impact by Geoff Henderson, WindFlow
Paul Gipe is the author of Wind Energy for the Rest of Us: A Comprehensive Guide to Wind Power and How to Use It.
Deeptech Startup Enabler, Advisor, Mentor, Int'l Market access & Renewable energy veteran
7 年Smaller turbines (sub MW) may find application in future, from smaller islands to I pay for what I need and where wind forms an important owned captive application
Yes Paul, I agree. And using the experience from developing these huge machines we could do it much cheaper than years before!
Managing Director at SyncWind Power Ltd; CTO at Triton Holdings Ltd
8 年Thanks Paul, yes Matthew might be thinking about the pure question of output (MWh/yr) per land area of the wind farm. If one assumes a 1/7th power law the height issue becomes significant and output per land area favours larger turbines (or at least taller ones as you say). But the 1/7th power law doesn't apply universally, especially not on ridgy sites which have the best wind resource. Te Rere Hau (in Paul's photo) has negative wind shear above 25-30 m so our 30 m hub height works really well. (Ultimately output per dollar is what really matters which is a different thing again.) And in any event, my main point about visual impact is in terms of output per land area of the ZVI of the wind farm. And this effect (a factor of 3-8) swamps any effect of wind shear on output per land area of the wind farm.
Renewables Engineer
8 年The inter turbine spacing argument might work if 'size' was defined by rotor diameter alone. However in practice, larger turbines also have higher hub heights. As wind speeds increase with height due to wind shear, energy yield also increases regardless of rotor size. This is particularly important in low wind speed regions where we are already seeing hub heights over 150m.