# Solar panels on wind turbine towers **URL:** \ **Category:** Factual Questions\ **Created:** [March 25, 2019, 6:36pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522 "2019-03-25T18:36:50Z")\ **Posts on this page:** 13\ **Page:** 3
**Author:** ![Shodan](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@Shodan](https://boards.straightdope.com/u/Shodan)\ **Post date:** [March 27, 2019, 6:34pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/41 "2019-03-27T18:34:59Z")
> [@kanicbird](#): > > The way it works is you can bank excess power so one doesn’t have to produce it at the time you are using the power. I get what you are saying, but it touches on another drawback of solar (and wind). You aren’t really banking the power - you get credit for it on your bill, but the energy itself isn’t stored. It is used elsewhere in the system. So at night, or when it is raining or whatever, the power has to be generated somewhere else, even if you aren’t being charged for it. It is difficult and not very cost-efficient to store energy. It’s not like you can just charge up a whole big bunch of batteries and then pull the electricity out of them at night. Battery technology isn’t that advanced, although research continues. That’s why electric cars are expensive and heavy - storing enough energy to drive the vehicle is hard to do. Solar panels can help meet demand at its peak, during the day, and that’s fine. But it is much the same with wind turbines - they don’t work unless the wind is blowing above a certain speed, and very often it doesn’t, and solar panels don’t work at night, or when it isn’t sunny. So you need a constant source of power, even in areas where solar or wind is useable some or most of the time. Regards, Shodan ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [March 27, 2019, 7:35pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/42 "2019-03-27T19:35:49Z")
> [@Stranger\_On\_A\_Train](#): > > Large solar panels attached to the tower would create more drag, interfere with the rotor, requiring the nacelle to be much longer and the overall diameter and strength of the tower to be greater to accommodate, and of course would be a massive pain in the ass to install and maintain in a highly elevated position. Wind towers are made tall and placed in locations specifically because there are regular high winds at that location, and it is obviously not desirable to handle large flat assemblies in wind even if there were some practical way to mount them that wouldn’t interfere with the rotor. Wind turbine towers are about 60 to 80 meters tall, possibly some are taller. The blade lengths are typically only half the height of their tower. Since I suggested using only the bottom 10 to 20 meters, even for the short 60 meter towers, there will still be a gap of at least 10 meters between the top of the panels and the lowest point the blades reach. There should be no interference with the rotor. In fact, the blades may never even shadow the panels, although that will depend on the latitude and how big the gap between the blade and panels is. > [@](#): > > There is a lot of open space in the American Southwest that also has an ideal climate and an almost ideal latitude within the continental United States, and many of these areas are contaminated with mine tailings or are otherwise undesirable for development. There is literally no reason to add great expense and inconvenience to the construction of wind turbines to save a very small amount of ground space. Those Southwest locations are great for powering the cities in the Southwest. What about powering the cities in the Midwest (where there are, in fact, lots of wind turbines)? That’s a long way to transmit the power and transmission losses will be great. Better to add more power generation closer to the cities. > [@Ruken](#): > > So the panels will be curved? Probably not. That would require custom made panels. Even if every wind turbine tower has them added, it probably wouldn’t be cost effective to make them. Consider that not all towers are the same size, so there would need to be several different curvatures. Instead, mount them so the long dimension is vertical and the center line of the panel is touching the tower. The edges will stick out a small amount, but not very far. Since this is a windy area, those edges will have to be braced to keep the panel from moving with the wind. Note that each panel will point in a slightly different direction than its left and right neighbors. This is OK, since the Sun moves throughout the day; each panel will get its time when the Sun is shining almost directly on it. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 27, 2019, 7:39pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/43 "2019-03-27T19:39:52Z")
> [@dtilque](#): > > OK, lots of good answers, but obviously I didn’t make something clear. In the OP, I imagined the solar panels would be very close to the tower, not extending outward significantly in any direction. So there shouldn’t be much more wind resistance than the tower already produces. If they’re made flush with the tower surface, there wouldn’t be any more. You need to understand aerodynamics. Wind turbine towers are designed to maximize ‘laminar flow’ around them, because putting a big tower in places of high winds generates huge aerodynamic loads. So having the wind flow smoothly around them is critical. if a solar panel sticks put even a few inches it could trip the laminar flow and create turbulent flow which will drive up the forces on the tower substantially, and I’m guessing could also mess up the turbines that might be behind that flow. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [March 27, 2019, 8:23pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/44 "2019-03-27T20:23:18Z")
> [@Shodan](#): > > I get what you are saying, but it touches on another drawback of solar (and wind). You aren’t really banking the power … > …So you need a constant source of power, even in areas where solar or wind is useable some or most of the time. > > Regards, > Shodan Yes I know how it works, I was talking here about the way the economics of solar work (at least in my state). And why it is economically advantageous for businesses to install solar beyond that of homeowners. It is due to a aspect of tariff rates which has give them a much bigger benefit from what was really intended to charge big businesses (or big commercial users of power) more for power. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 27, 2019, 9:11pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/45 "2019-03-27T21:11:21Z")
> [@kanicbird](#): > > Yes I know how it works, I was talking here about the way the economics of solar work (at least in my state). And why it is economically advantageous for businesses to install solar beyond that of homeowners. It is due to a aspect of tariff rates which has give them a much bigger benefit from what was really intended to charge big businesses (or big commercial users of power) more for power. When big business install solar power right now, they are doing it for two reasons: 1) To take advantage of subsidies that are available that make it worthwhile, and 2) for PR purposes, especially if they’ve been criticized for their power use or whatever. But maybe I’m behind the times. Can you name some places where businesses are making serious investments in solar power without subsidies for either the construction, or artificially high prices for selling power back to the grid? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [March 27, 2019, 9:25pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/46 "2019-03-27T21:25:34Z")
> [@Sam\_Stone](#): > > You need to understand aerodynamics. Wind turbine towers are designed to maximize ‘laminar flow’ around them, because putting a big tower in places of high winds generates huge aerodynamic loads. So having the wind flow smoothly around them is critical. if a solar panel sticks put even a few inches it could trip the laminar flow and create turbulent flow which will drive up the forces on the tower substantially, and I’m guessing could also mess up the turbines that might be behind that flow. It also adds considerably to the structural loads and will require mounting provisions which adds to cost, all for the supposed benefit of a saving a few tens of square meters of space and nothwithstanding that this is at just about the worst possibly angle of incidence for insolation short of pointing the panel at the ground. It would be a rare and extemely population dense space that does not have the equivalent ground or rooftop space for much cheaper than adding such provisions to wind towers, and these aren’t areas that would host a wind turbine to begin with. This is a solution to a problem that doesn’t exist. Stranger ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [March 27, 2019, 9:27pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/47 "2019-03-27T21:27:45Z")
Isn’t the grid 60 cycle AC? I believe the output of solar panels is direct current (DC). Although AC can ride on DC, I see no advantage to having the grid’s AC riding on a DC level. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 27, 2019, 9:30pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/48 "2019-03-27T21:30:17Z")
> [@Stranger\_On\_A\_Train](#): > > It also adds considerably to the structural loads and will require mounting provisions which adds to cost, all for the supposed benefit of a saving a few tens of square meters of space and nothwithstanding that this is at just about the worst possibly angle of incidence for insolation short of pointing the panel at the ground. It would be a rare and extemely population dense space that does not have the equivalent ground or rooftop space for much cheaper than adding such provisions to wind towers, and these aren’t areas that would host a wind turbine to begin with. This is a solution to a problem that doesn’t exist. > > Stranger Agreed. Also, Wind towers are often located in areas that are not necessarily getting the most daily sunlight. Mountain passes, for example. The constant high winds can often come with greater than average local cloud cover. ---
**Author:** ![EdelweissPirate](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@EdelweissPirate](https://boards.straightdope.com/u/EdelweissPirate)\ **Post date:** [March 27, 2019, 10:15pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/49 "2019-03-27T22:15:49Z")
> [@Stranger\_On\_A\_Train](#): > > This is a solution to a problem that doesn’t exist. I’d go further still: this is a solution to a problem that hasn’t been defined. The original question—“is there any reason solar panels aren’t put on wind turbine towers?”—was answered in the first reply: yes. There’s not enough area to make it worthwhile. The OP has implied that the real question here is “given a wind farm that produces X power and takes up Y land, how can we increase X while holding Y constant?” As others have pointed out, the most economically efficient answer to that question is usually “pull down the nacelle (and probably the tower) and install a turbine with a bigger blade disc in its place.” But if that’s the real question, then I don’t understand why the OP is fixated on using solar panels attached to the to the towers. Many others have pointed out the myriad reasons why this isn’t done. Of course, the most compelling reason is that for any given amount of capital, putting panels on towers is going to cost way more per unit of generated power than most other options. Dtilque, is my second paragraph a reasonable restatement of your question? If not, what are you really asking about? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [March 27, 2019, 11:07pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/50 "2019-03-27T23:07:14Z")
> [@Ranger\_Jeff](#): > > Isn’t the grid 60 cycle AC? I believe the output of solar panels is direct current (DC). Although AC can ride on DC, I see no advantage to having the grid’s AC riding on a DC level. They can spin the solar panels really fast around the tower to accomplish this. Or just use a grid tied inverter. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [March 28, 2019, 10:46am UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/51 "2019-03-28T10:46:15Z")
> [@dtilque](#): > > Probably not. That would require custom made panels. Even if every wind turbine tower has them added, it probably wouldn’t be cost effective to make them. Consider that not all towers are the same size, so there would need to be several different curvatures. > > Instead, mount them so the long dimension is vertical and the center line of the panel is touching the tower. The edges will stick out a small amount, but not very far. Since this is a windy area, those edges will have to be braced to keep the panel from moving with the wind. Note that each panel will point in a slightly different direction than its left and right neighbors. This is OK, since the Sun moves throughout the day; each panel will get its time when the Sun is shining almost directly on it. So you are advocating for the panels to stick out and create more shadow. You can’t stick stuff on the tower without making the shadow bigger. You can minimize this by making the panels flush and curved. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [March 28, 2019, 10:49am UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/52 "2019-03-28T10:49:44Z")
> [@Ranger\_Jeff](#): > > Isn’t the grid 60 cycle AC? I believe the output of solar panels is direct current (DC). Although AC can ride on DC, I see no advantage to having the grid’s AC riding on a DC level. It’s generally assumed that solar power will be inverted. That’s just part of the cost. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [March 28, 2019, 1:32pm UTC](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522/53 "2019-03-28T13:32:17Z")
> [@Ruken](#): > > So you are advocating for the panels to stick out and create more shadow. You can’t stick stuff on the tower without making the shadow bigger. You can minimize this by making the panels flush and curved. Yes, but it’d be a very modest addition to the shadow, probably less than one percent. OK, everyone. You’ve convinced me this isn’t a good thing to do. I’m going to stop contributing to this thread. Thank you for your contributions. [Previous page](https://boards.straightdope.com/t/solar-panels-on-wind-turbine-towers/831522.md?page=2)