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There's a recent talk here where Musk discusses what he thinks of the future of energy, though I don't think he goes into wind vs. solar specifically (he does e

There's a recent talk here where Musk discusses what he thinks of the future of energy, though I don't think he goes into wind vs. solar specifically (he does explain in the Q&A at the end why he doesn't think biofuels make sense). http://www.treehugger.com/green-investments/tesla-ceo-elon-musk-gives-hour-long-speech-university-oxford-video-and-audio-q-a.html http://www.treehugger.com/green-investments/tesla-ceo-elon-m...

jessriedel 14y ago
Thanks much.
Someone 14y ago
I could not find him comapring solar and wind, either. On the risk that you already considered all of these, here are some reasons I can think of: http://www.withouthotair.com/c4/page_32.shtml http://www.withouthotair.com/c4/page_32.shtml gives 2W/m^2 for wind and http://www.withouthotair.com/c6/page_39.shtml http://www.withouthotair.com/c6/page_39.shtml gives 22W/m^2 for photovoltaic. Yes, there are places where you can get much more energy from wind per m^2, but you can get that photovoltaic output almost everywhere. It also is easier to start a solar business than one based on wind power. With solar, you can start small and scale up. With wind, you almost have to start with huge structures, as they have better ROI (higher = faster wind = way more energy). Building such larger structures means that you no longer operate in the B2C market. He may not like that. Also, he may not like having to spend effort and time getting building permission for those structures. He may also think photovoltaics will get cheaper faster than wind. Finally, it might be just a personal preference. To me, wind has more of a blue collar feel than photovoltaics (someone will get his hands greasy operating a wind farm). That does not make me dislike it, but might have swung the choice for him.
- sliverstorm 14y ago
  Is he actually rooting for photovoltaics? I personally have a number of issues specifically with photovoltaics that I do not have with many other types of solar. IMO any kind of solar "plant" shouldn't be using photovoltaics.
  - ak217 14y ago
    Could you explain why?
    - ams6110 14y ago
      I would speculate (but don't know) that concentration of the heat energy to power a more conventional steam generation plant would be more efficient, at least beyond a certain scale. The best photovoltaic panels are about 20% efficient under optimal conditions.
      - ak217 14y ago
        They are also closer to the consumer, negating a big chunk of the transmission losses. Also, while thermal electric plants may be more efficient at large scale, I'm not sure how that works at small scale, or if there is a difference in how much capacity they lose in cloudy weather compared to photovoltaics. Actually, I wonder what the ratio of installed photovoltaics to thermals is per region and generator scale.
    - ihsw 14y ago
      The alternatives seem simpler, specifically solar thermal collectors[1] where they can be used in conjunction with steam turbines and molten salt heat storage. The most obvious disadvantage is that energy collection ability drops sharply on clouded days and it relies entirely on clear skies. [1] http://en.wikipedia.org/wiki/Solar_heating http://en.wikipedia.org/wiki/Solar_heating
      - ak217 14y ago
        I don't understand how a solar thermal collector is in any way simpler than a photovoltaic array. Actually, it seems more complex to me. Again, could you explain?
        sliverstorm 14y ago
        They are simpler than photovoltaics in the sense that a mechanic can repair them. I like them because they: - Use simple materials, not a bunch of rare earth metals that the USA doesn't have - Will last as long as you maintain them (to my knowledge) unlike solar panels - Have better efficiency compared to solar panels You are right that they are not as "simple" as slapping a panel on a flat surface and wiring it up. Clearly, they are not suited for installation on houses. However, power plants have always used more sophisticated systems because they can handle the tradeoffs to reap the rewards.
- jessriedel 14y ago
  > 2W/m^2 for wind and ... 22W/m^2 for photovoltaic. This is a misleading number for my point that wind is denser than solar. For solar, the 22W/m^2 is spread out evenly an area, and you must put something (either photovoltaic or a mirror) to collect it. For wind, you only need a single turbine to effectively cover a relatively large area. The density number comes from the fact that, by virtue of how winds are generated and blow, you can't just stick a second turbine right next to the first one. From a cost per kWh perspective, the important number is more like the number of watts generated by single turbine with a 1 meter x 1 meter footprint.
  - Someone 14y ago
    Misleading in one sense, but revealing in another. That 10MW wind turbine on your 10,000m^2 of land will only get to that output by using wind blowing into it from other land. So, if your neighbor builds another such turbine on his land, your output will drop. So, you will have to pay your neighbors for not building such a turbine on their land. In that sense, you really need that area to get that output. Having said that, ROI of wind turbines seems to be way better than that for photovoltaics, in almost every aspect. https://sites.google.com/site/anatomyofglobalclimatechangevj/data-and-analysis https://sites.google.com/site/anatomyofglobalclimatechangevj..., for example, gives you about 6 months to recover the energy investment of building a wind mill and 3 years for photovoltaics.
    - jessriedel 14y ago
      > So, if your neighbor builds another such turbine on his land, your output will drop. This is not an important effect. The optimal spacing for wind turbines is 5-15 times the rotor diameter, and the largest turbines are 75ft in diameter, giving a largest spacing of roughly ~ 1/4 mi. In the rare cases that this is an issue, property liens can handle the conflict.
      - Someone 14y ago
        The largest turbines are more like 300ft in diameter (http://en.wikipedia.org/wiki/Wind_turbine_design#Turbine_size http://en.wikipedia.org/wiki/Wind_turbine_design#Turbine_siz...) Also, the effect is important. At 1/4 mile distance, you can only place about 20 or so on a square mile of land. Looking at http://en.wikipedia.org/wiki/Wind_turbine#Horizontal_axis_wind_turbines http://en.wikipedia.org/wiki/Wind_turbine#Horizontal_axis_wi..., that gives you less than 18MW peak power. That same square mile has 2M plus m^2. So, you would need only 10W per m^2 peak solar power to beat that wind turbine. Yes, there is lots of hand waiving here. For example, I am assuming equal duty cycle; that will vary with location. The crux still is that there is way less wind power than solar per m^2.

jessriedel 14y ago

Thanks much.

Someone 14y ago

I could not find him comapring solar and wind, either. On the risk that you already considered all of these, here are some reasons I can think of: http://www.withouthotair.com/c4/page_32.shtml http://www.withouthotair.com/c4/page_32.shtml gives 2W/m^2 for wind and http://www.withouthotair.com/c6/page_39.shtml http://www.withouthotair.com/c6/page_39.shtml gives 22W/m^2 for photovoltaic. Yes, there are places where you can get much more energy from wind per m^2, but you can get that photovoltaic output almost everywhere. It also is easier to start a solar business than one based on wind power. With solar, you can start small and scale up. With wind, you almost have to start with huge structures, as they have better ROI (higher = faster wind = way more energy). Building such larger structures means that you no longer operate in the B2C market. He may not like that. Also, he may not like having to spend effort and time getting building permission for those structures. He may also think photovoltaics will get cheaper faster than wind. Finally, it might be just a personal preference. To me, wind has more of a blue collar feel than photovoltaics (someone will get his hands greasy operating a wind farm). That does not make me dislike it, but might have swung the choice for him.

sliverstorm 14y ago
Is he actually rooting for photovoltaics? I personally have a number of issues specifically with photovoltaics that I do not have with many other types of solar. IMO any kind of solar "plant" shouldn't be using photovoltaics.
- ak217 14y ago
  Could you explain why?
  - ams6110 14y ago
    I would speculate (but don't know) that concentration of the heat energy to power a more conventional steam generation plant would be more efficient, at least beyond a certain scale. The best photovoltaic panels are about 20% efficient under optimal conditions.
    - ak217 14y ago
      They are also closer to the consumer, negating a big chunk of the transmission losses. Also, while thermal electric plants may be more efficient at large scale, I'm not sure how that works at small scale, or if there is a difference in how much capacity they lose in cloudy weather compared to photovoltaics. Actually, I wonder what the ratio of installed photovoltaics to thermals is per region and generator scale.
  - ihsw 14y ago
    The alternatives seem simpler, specifically solar thermal collectors[1] where they can be used in conjunction with steam turbines and molten salt heat storage. The most obvious disadvantage is that energy collection ability drops sharply on clouded days and it relies entirely on clear skies. [1] http://en.wikipedia.org/wiki/Solar_heating http://en.wikipedia.org/wiki/Solar_heating
    - ak217 14y ago
      I don't understand how a solar thermal collector is in any way simpler than a photovoltaic array. Actually, it seems more complex to me. Again, could you explain?
      - sliverstorm 14y ago
        They are simpler than photovoltaics in the sense that a mechanic can repair them. I like them because they: - Use simple materials, not a bunch of rare earth metals that the USA doesn't have - Will last as long as you maintain them (to my knowledge) unlike solar panels - Have better efficiency compared to solar panels You are right that they are not as "simple" as slapping a panel on a flat surface and wiring it up. Clearly, they are not suited for installation on houses. However, power plants have always used more sophisticated systems because they can handle the tradeoffs to reap the rewards.
jessriedel 14y ago
> 2W/m^2 for wind and ... 22W/m^2 for photovoltaic. This is a misleading number for my point that wind is denser than solar. For solar, the 22W/m^2 is spread out evenly an area, and you must put something (either photovoltaic or a mirror) to collect it. For wind, you only need a single turbine to effectively cover a relatively large area. The density number comes from the fact that, by virtue of how winds are generated and blow, you can't just stick a second turbine right next to the first one. From a cost per kWh perspective, the important number is more like the number of watts generated by single turbine with a 1 meter x 1 meter footprint.
- Someone 14y ago
  Misleading in one sense, but revealing in another. That 10MW wind turbine on your 10,000m^2 of land will only get to that output by using wind blowing into it from other land. So, if your neighbor builds another such turbine on his land, your output will drop. So, you will have to pay your neighbors for not building such a turbine on their land. In that sense, you really need that area to get that output. Having said that, ROI of wind turbines seems to be way better than that for photovoltaics, in almost every aspect. https://sites.google.com/site/anatomyofglobalclimatechangevj/data-and-analysis https://sites.google.com/site/anatomyofglobalclimatechangevj..., for example, gives you about 6 months to recover the energy investment of building a wind mill and 3 years for photovoltaics.
  - jessriedel 14y ago
    > So, if your neighbor builds another such turbine on his land, your output will drop. This is not an important effect. The optimal spacing for wind turbines is 5-15 times the rotor diameter, and the largest turbines are 75ft in diameter, giving a largest spacing of roughly ~ 1/4 mi. In the rare cases that this is an issue, property liens can handle the conflict.
    - Someone 14y ago
      The largest turbines are more like 300ft in diameter (http://en.wikipedia.org/wiki/Wind_turbine_design#Turbine_size http://en.wikipedia.org/wiki/Wind_turbine_design#Turbine_siz...) Also, the effect is important. At 1/4 mile distance, you can only place about 20 or so on a square mile of land. Looking at http://en.wikipedia.org/wiki/Wind_turbine#Horizontal_axis_wind_turbines http://en.wikipedia.org/wiki/Wind_turbine#Horizontal_axis_wi..., that gives you less than 18MW peak power. That same square mile has 2M plus m^2. So, you would need only 10W per m^2 peak solar power to beat that wind turbine. Yes, there is lots of hand waiving here. For example, I am assuming equal duty cycle; that will vary with location. The crux still is that there is way less wind power than solar per m^2.