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Wind power: Difference between revisions
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Wind turbines convert wind to electricity. | Wind turbines convert wind to electricity. | ||
{{minor|A lot of people incorrectly call wind turbines "windmills". But in fact windmills are a much older technology, which use the wind to mill grains ''mechanically'' (no electricity involved).}} | {{minor|Side note: A lot of people incorrectly call wind turbines "windmills". But in fact windmills are a much older technology, which use the wind to mill grains ''mechanically'' (no electricity involved).}} | ||
{{considerations}}__NOTOC__ <!-- The above table replaces ''most'' of the table of contents. --> | |||
==Intermittency== | |||
{{sum|Needs [[energy storage]]}} | |||
__NOTOC__ <!-- The above table replaces ''most'' of the table of contents. --> | |||
Wind power is even more intermittent than [[solar]]. There can be months where the wind blows strongly, and months where it barely blows at all. Also, wind turbines can't function when the wind blows ''too'' hard. | Wind power is even more intermittent than [[solar]]. There can be months where the wind blows strongly, and months where it barely blows at all. Also, wind turbines can't function when the wind blows ''too'' hard. | ||
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Scaling up [[energy storage]] is already a challenge, even for solar which only needs about a day's worth of energy storage in general. Wind might need several weeks worth{{x|i.e. could easily need 40 times more battery capacity for the same ''average'' energy consumption rate}}. | Scaling up [[energy storage]] is already a challenge, even for solar which only needs about a day's worth of energy storage in general. Wind might need several weeks worth{{x|i.e. could easily need 40 times more battery capacity for the same ''average'' energy consumption rate}}. | ||
Wind energy is probably best stored via [[hydrogen gas]], which doesn't have a ''fixed capacity'' the way batteries do. {{x|A battery can only store a fixed amount of energy at any given time. But hydrogen could be produced and stockpiled if necessary (as long as [[hydrogen gas/safety|safety]] concerns are addressed). Hydrogen production units (electrolyzers) still have a fixed ''power'' rating: There's a limit to how much hydrogen can be produced ''per unit of time''.}} | |||
==Geography== | |||
{{sum|Limitation}} | |||
The best places for wind turbines [[/Geography|aren't usually near where people live]]. In most cases, the distance is far enough that power lines wouldn't even be viable. {{qn}} | The best places for wind turbines [[/Geography|aren't usually near where people live]]. In most cases, the distance is far enough that power lines wouldn't even be viable. {{qn}} | ||
This might not be an issue if | This might not be an issue if hydrogen (as described above) is the main solution for the [[energy storage]]. Instead of power lines, the wind turbines would generate [[hydrogen gas]] which would be [[transportation of hydrogen gas|transported]] and used for [[energy]] elsewhere. | ||
We'd need to estimate the full [[EROI]] of such a system, to make sure it's [[Term:viable|viable]].{{rn}} | We'd need to estimate the full [[EROI]] of such a system, to make sure it's [[Term:viable|viable]].{{rn}} | ||
==Rare earth magnets== | |||
To build a wind turbine{{x|specifically, the ''dynamo'' component which converts spinning motion into electricity}}requires either ''strong magnets'' | {{sum|Probably reasonable{{rn}} }} | ||
To build a wind turbine{{x|specifically, the ''dynamo'' component which converts spinning motion into electricity}}requires either: | |||
* ''strong magnets'', made with rare earth metals{{qn}} | |||
* or a complex gearbox, which requires maintenance{{qn| - labor}}and isn't suited for offshore wind. | |||
{{pn|This section needs more research to determine which rare metals are needed, in what quantities, and whether there would be enough global [[mineral reserves]] to scale up wind power enough to replace fossil fuels or not.}} | {{pn|This section needs more research to determine which rare metals are needed, in what quantities, and whether there would be enough global [[mineral reserves]] to scale up wind power enough to replace fossil fuels or not.}} | ||
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--> | --> | ||
==Cement== | |||
{{sum|Reasonable}} | |||
The footing of a wind turbine requires a lot of concrete - a potential concern because cement production releases CO<sub>2</sub>. However, it turns out that the amount of CO<sub>2</sub> is '''not''' very significant: | The footing of a wind turbine requires a lot of concrete - a potential concern because cement production releases CO<sub>2</sub>. However, it turns out that the amount of CO<sub>2</sub> is '''not''' very significant: | ||
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}} | }} | ||
{{calc | {{calc | ||
|<nowiki>wind.rq_concrete * concrete.cement_by_mass * cement.ghg_by_mass | |<nowiki>wind.rq_concrete / wind.capacity_factor * concrete.cement_by_mass * cement.ghg_by_mass</nowiki> | ||
|<nowiki>days gasoline.ghg_by_energy</nowiki> | |<nowiki>days gasoline.ghg_by_energy</nowiki> | ||
}} | }} | ||
</tab> | </tab> | ||
A wind turbine's cement CO<sub>2</sub> footprint "pays itself off" in about 20 days, when you compare the wind power with the fossil fuels it would typically replace. {{x|Note that this equation compares [[Term:primary|primary]]-energy from wind (intermittent electricity) with [[Term:primary|primary]]-energy from gasoline (which is a sort of "average" fossil fuel in terms of carbon-per-energy; coal has a bit more carbon while natural gas has a bit less, but they're [[:File:fossil-fuels-ghg-by-energy.png|close enough]] for the purpose of this estimate). Additional energy losses in coal or natural gas power plants would mean that the wind turbine cement CO<sub>2</sub> pays itself off even sooner. }} | |||
<small>This is pretty reasonable considering that a wind turbine's lifespan is about 20 ''years''.<ref>United States Environmental Protection Agency (EPA) - [https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100IL8K.TXT Renewable Energy Fact Sheet: Wind Turbines - epa nepis]</ref></small> | <small>This is pretty reasonable considering that a wind turbine's lifespan is about 20 ''years''.<ref>United States Environmental Protection Agency (EPA) - [https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100IL8K.TXT Renewable Energy Fact Sheet: Wind Turbines - epa nepis]</ref></small> | ||
== | ==E.R.O.I.== | ||
[[Energy return on investment]]: About 19. | {{sum|Reasonable}} | ||
[[Energy return on investment]] (EROI): About 19. | |||
In other words: wind turbines, over their entire lifespan, produce about 19 times as much energy as it takes to make them.<ref>Hall, C., et al. (2013) EROI of different fuels and the implications for society. Energy Policy (64), 141-152.</ref> There would still need to be some [[fossil fuels]] invested into wind power to "get the ball rolling". | In other words: wind turbines, over their entire lifespan, produce about 19 times as much energy as it takes to make them.<ref>Hall, C., et al. (2013) EROI of different fuels and the implications for society. Energy Policy (64), 141-152.</ref> There would still need to be some [[fossil fuels]] invested into wind power to "get the ball rolling". | ||
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Maybe there are some other wind turbine designs that have a better EROI. {{rn}} | Maybe there are some other wind turbine designs that have a better EROI. {{rn}} | ||
==Land use== | |||
{{sum|Reasonable}} | |||
Per unit of energy, wind needs far more [[land]] than solar{{x|in terms of the spacing between the wind turbines; not in terms of the footing size of the turbines}}. However, wind turbines can coexist with farm land{{x|whether crop land or pasture}}, without interfering with [[crop yields]]. Crop land alone might provide enough space for enough wind turbines to meet global energy demands: | Per unit of energy, wind needs far more [[land]] than solar{{x|in terms of the spacing between the wind turbines; not in terms of the footing size of the turbines}}. However, wind turbines can coexist with farm land{{x|whether crop land or pasture}}, without interfering with [[crop yields]]. Crop land alone might provide enough space for enough wind turbines to meet global energy demands: | ||
{{dp | {{dp | ||
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There should be '''no need''' to destroy natural habitats to build wind farms. | There should be '''no need''' to destroy natural habitats to build wind farms. | ||
=== | ==Noise== | ||
{{sum|{{rn}} }} | |||
{{empty}} | |||
==Bird deaths== | |||
{{sum|{{rn}} }} | |||
{{empty}} | {{empty}} | ||
==Recyclability== | |||
{{sum|{{rn}} }} | |||
{{empty}} | {{empty}} | ||