3 ms·

Initial hot take: I'm not sure they're measuring efficiency in a way that's really meaningful to me? There are so many ways you could measure it. You could mea

Initial hot take: I'm not sure they're measuring efficiency in a way that's really meaningful to me? There are so many ways you could measure it. You could measure it as the % of wind energy passing through the turbine's plane that is taken out of the air, or the the efficiency of using that energy to get the rotor turning, or the efficiency of converting the rotor's kinetic energy to electrical energy. (edit: Or I could, y'know, do the sensible thing and check the article. They're measuring power output for a given wind speed and direction. Which I think means, in effect, all of that end-to-end.) But I'm not sure any of those are, in and of themselves, what really matters at scale. The more interesting questions, I'm guessing, are things like, "How much energy can we get out of a plot of land of a given size?", or, "How much energy can we generate for a given cost to install and maintain?" Both of which, I would assume, are more difficult to directly extrapolate from thermodynamic efficiency in wind turbines than they are for something like photovoltaics, because of the "moving parts" factor.

7952 6y ago
I think this is efficiency in terms of much energy you can extract for a given area of sea or land. Wake effects mean that wind turbines cannot be placed in a particular zone downwind of another turbine. If wake effects are lower then you could potentially get a higher density of turbines in a given area. This is something that is already considered in terms of turbine height and placement. Sometimes they are placed at closer intervals along the perimeter of the zone and then lower densities within. Of course lots of factors are considered with the final "efficiency" being about getting the highest return for an investment.
- brianwawok 6y ago
  If land is your dominating cost factor, its how many kw per acre can you generate. So dense circular turbines seem good. If the cost to produce the turbines is the dominating cost factor, and traditional turbines are "cheaper" to build, it could be a win in some cases to use more land with normal wind turbines. The more you spread them, the less problem you have with wake on downstream turbines. Or it could vary based on land value of where you are installing a given plant.
  - 7952 6y ago
    But land value depends on what you can do with the land. It will always going to be more profitable to build a distribution center or yuppie condo but most sites cannot accommodate that. Wind turbines make sense when a land owner is trying to make more money out of an existing asset. Maybe it is moorland with sheep on it. The wind turbines supplement existing land use and give an extra source of revenue. The developer is competing with other developers. Once they have a land owner on board they will have a certain target they want to hit and will try and get away with as much as possible.
kempbellt 6y ago
> "How much energy can we get out of a plot of land of a given size?" I don't believe this is an answerable question in this format. The size of a plot says nothing of land topography, nor the average wind currents for any given timeframe. Wind farms are great tech, but adequate calculation of efficiency and cost/benefit is always subjective to individual installations. Solar farm efficiency calculations are easier because the variables at play are much more consistent. Essentially: panel efficiency * sun exposure * array size. I don't believe this formula translates to wind farms. Finding a more efficient design for wind-to-energy conversion is a lot like making an improvement in the "panel efficiency" part of solar arrays. Or maybe wind has an "array design" variable to consider since one turbine's design can affect the wind energy capacity of another. This isn't the same for solar, unless panels overlap during certain times of the day.
- mumblemumble 6y ago
  Yeah, that's more or less what I was getting at, albeit in less detail. Put topography and how it interacts with the wind and all of that under the category of "mechanics", I guess? But, in the simulation that this study is based on, it looked to me like they assumed flat terrain and laminar airflow coming into the field of turbines. Which I'm assuming happens in nature approximately never. So it's like, sure, maybe this turbine arrangement can get 15% greater power output under ideal conditions, but I don't think you can get from there to, "this is a clear win over the incumbent technology" anywhere near as easily as you could in the case of an photovoltaic efficiency improvement.

7952 6y ago

I think this is efficiency in terms of much energy you can extract for a given area of sea or land. Wake effects mean that wind turbines cannot be placed in a particular zone downwind of another turbine. If wake effects are lower then you could potentially get a higher density of turbines in a given area. This is something that is already considered in terms of turbine height and placement. Sometimes they are placed at closer intervals along the perimeter of the zone and then lower densities within. Of course lots of factors are considered with the final "efficiency" being about getting the highest return for an investment.

brianwawok 6y ago
If land is your dominating cost factor, its how many kw per acre can you generate. So dense circular turbines seem good. If the cost to produce the turbines is the dominating cost factor, and traditional turbines are "cheaper" to build, it could be a win in some cases to use more land with normal wind turbines. The more you spread them, the less problem you have with wake on downstream turbines. Or it could vary based on land value of where you are installing a given plant.
- 7952 6y ago
  But land value depends on what you can do with the land. It will always going to be more profitable to build a distribution center or yuppie condo but most sites cannot accommodate that. Wind turbines make sense when a land owner is trying to make more money out of an existing asset. Maybe it is moorland with sheep on it. The wind turbines supplement existing land use and give an extra source of revenue. The developer is competing with other developers. Once they have a land owner on board they will have a certain target they want to hit and will try and get away with as much as possible.

kempbellt 6y ago

> "How much energy can we get out of a plot of land of a given size?" I don't believe this is an answerable question in this format. The size of a plot says nothing of land topography, nor the average wind currents for any given timeframe. Wind farms are great tech, but adequate calculation of efficiency and cost/benefit is always subjective to individual installations. Solar farm efficiency calculations are easier because the variables at play are much more consistent. Essentially: panel efficiency * sun exposure * array size. I don't believe this formula translates to wind farms. Finding a more efficient design for wind-to-energy conversion is a lot like making an improvement in the "panel efficiency" part of solar arrays. Or maybe wind has an "array design" variable to consider since one turbine's design can affect the wind energy capacity of another. This isn't the same for solar, unless panels overlap during certain times of the day.

mumblemumble 6y ago
Yeah, that's more or less what I was getting at, albeit in less detail. Put topography and how it interacts with the wind and all of that under the category of "mechanics", I guess? But, in the simulation that this study is based on, it looked to me like they assumed flat terrain and laminar airflow coming into the field of turbines. Which I'm assuming happens in nature approximately never. So it's like, sure, maybe this turbine arrangement can get 15% greater power output under ideal conditions, but I don't think you can get from there to, "this is a clear win over the incumbent technology" anywhere near as easily as you could in the case of an photovoltaic efficiency improvement.