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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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''.}} | 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}} | ||
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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}} | ||
Latest revision as of 00:58, 22 November 2023
Wind power is a possible option for renewable energy.
Wind turbines convert wind to electricity.
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).
Intermittency
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.
[suitable wind speeds]
Most wind turbines can only generate power when wind speeds are between 3.5 m/s and 25 m/s.
[1]
This intermittency usually gets "filled in" with natural gas power plants, but that's not good enough if we want to phase out fossil fuels.
Having multiple wind farms might somewhat reduce the intermittency. But in practice, this doesn't seem to help much.[2]
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
Wind energy is probably best stored via hydrogen gas, which doesn't have a fixed capacity the way batteries do.
Geography
The best places for wind turbines aren't usually near where people live. In most cases, the distance is far enough that power lines wouldn't even be viable. [QUANTIFICATION needed]
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 transported and used for energy elsewhere.
We'd need to estimate the full EROI of such a system, to make sure it's viable.[RESEARCH needed]
Rare earth magnets
To build a wind turbine
- strong magnets, made with rare earth metals[QUANTIFICATION needed]
- or a complex gearbox, which requires maintenance[QUANTIFICATION needed - labor]and isn't suited for offshore wind.
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.
Cement
The footing of a wind turbine requires a lot of concrete - a potential concern because cement production releases CO2. However, it turns out that the amount of CO2 is not very significant:
McGraw-Hill Encyclopedia of Science and Technology. "Volume generally assumed for the density of hardened concrete is 150 lb/ft^3. (2400 kg/m^3)"
Read more: https://hypertextbook.com/facts/1999/KatrinaJones.shtml
SUSTAINABLE CONCRETE FOR WIND TURBINE FOUNDATIONS www.bnl.gov › isd › documents
"Turbines in the 1 to 2 MW range typically use 130 to 240 m3 of concrete for the foundation"
https://css.umich.edu/factsheets/wind-energy-factsheet
(calculation loading)
A wind turbine's cement CO2 footprint "pays itself off" in about 20 days, when you compare the wind power with the fossil fuels it would typically replace.
This is pretty reasonable considering that a wind turbine's lifespan is about 20 years.[3]
E.R.O.I.
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.[4] There would still need to be some fossil fuels invested into wind power to "get the ball rolling".
Maybe there are some other wind turbine designs that have a better EROI. [RESEARCH needed]
Land use
Per unit of energy, wind needs far more land than solar
- This is per megawatt capacity (peak), not per average output.
- Stats can vary tremendously based on how windy the location is.
- This stat is based on 172 different wind projects scattered throughout the USA.
- Consider variance: (34.5 +/- 22.4) hectares/MW
- This is the total land use, including the spacing between turbines in a wind farm.
- This is much bigger than [wind.rq_land_disturbed] which is just the land directly impacted by constructing the turbine itself.
Citation:
Land-Use Requirements Of Modern Wind Power Plants In The United States
(Paul Denholm, Maureen Hand, Maddalena Jackson, and Sean Ong)
Page 16
Does not include the fuel used in generating electricity. See [energy.tes] for that.
Citation: "Key World Energy Statistics 2020" IEA
- Page 47 - Simplified energy balance table - World energy balance, 2018
https://css.umich.edu/factsheets/wind-energy-factsheet
(calculation loading)[discussion needed]~ wind.rq_land
is based in the status quo of wind projects, which are probably on land that's more windy than average. If wind turbines were to be on average crop land, the energy productivity may be less. Then again, there's also pasture and barren land where wind turbines could be placed too, and there's also offshore wind. ~ If all countries were developed, we'd need more than just energy.tfc
- but then again, we don't need to get all our energy from wind; rooftop solar also has a lot of productive potential.
There should be no need to destroy natural habitats to build wind farms.
Noise
This section has not been filled in yet.
Bird deaths
This section has not been filled in yet.
Recyclability
This section has not been filled in yet.
References
- ↑ DASH, Meteorologically Defined Limits to Reduction in the Variability of Outputs from a Coupled Wind Farm System in the Central US [Online], Available: http://dash.harvard.edu/bitstream/handle/1/10981611/Meteorologically%20defined%20limits%20to%20reduction%20in%20the%20variability%20of%20outputs%20from%20a%20coupled%20wind%20farm%20system%20in%20the%20Central%20US_1.pdf?sequence=6
- ↑ David JC McKay, Sustainable energy - without the hot air [Online], Available: http://www.inference.phy.cam.ac.uk/withouthotair/c26/page_187.shtml
- ↑ United States Environmental Protection Agency (EPA) - Renewable Energy Fact Sheet: Wind Turbines - epa nepis
- ↑ Hall, C., et al. (2013) EROI of different fuels and the implications for society. Energy Policy (64), 141-152.