Wind power
Wind power is a possible option for renewable energy.
Wind turbines convert wind to electricity.
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
#Intermittency | Needs energy storage |
#Geography | Major limitation |
#Rare earth magnets | Possible problem [RESEARCH needed] |
#Cement | Not a significant problem |
#EROI | Manageable |
#Land use | Manageable |
#Noise | [RESEARCH needed] |
#Recyclability | [RESEARCH needed] |
Intermittency
Wind power is even more intermittent than solar. There can be weeks where the wind blows strongly
Having multiple wind farms might somewhat reduce the intermittency. But in practice, this doesn't seem to help much.[1]
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.
Maybe wind energy could be stored via hydrogen, which doesn't have a fixed capacity the way batteries do.
Most wind turbines can only generate power when wind speeds are between 3.5 m/s and 25 m/s.
[2]
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 wind/hydrogen (as described above) is the main solution. 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
This page 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)
Compared to burning gasoline
This is pretty reasonable considering that a wind turbine's lifespan is about 20 years.[3]
EROI
Energy return on investment: 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
There should be no need to destroy natural habitats to build wind farms.
Noise
This section has not been filled in yet.
Recyclability
This section has not been filled in yet.
References
- ↑ David JC McKay, Sustainable energy - without the hot air [Online], Available: http://www.inference.phy.cam.ac.uk/withouthotair/c26/page_187.shtml
- ↑ 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
- ↑ 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.