Wind Energy

Image: Unsplash. “Photo by American Public Power Association on Unsplash.” Unsplash.com, 23 Oct. 2017, unsplash.com/photos/windmills-on-green-field-under-white-sky-during-daytime-eIBTh5DXW9w. Accessed 21 Nov. 2023.

Power Considerations

Wind speed averages and signs of flagging (the permanent deformation of trees and other vegetation by wind) can be used as an estimate to gauge what the wind looks like in specific locations, but this is only an estimate. Tree and building proximity can affect wind, so in most cases contractors will come in to collect actual site data to understand exactly what the wind in your location looks like. However, it is worth noting that this process can be cost- and time-intensive because it involves collecting wind measurements for a full year1.

Site data was not available, so to make recommendations for wind power implementation we looked at wind speed averages and tree cover2. Wind speeds of at least 9 to 10 miles per hour are preferable for installation of wind turbines. Low tree cover is also required due to the way it can obstruct wind speed1. We were able to find data on tree cover in hectares3 for each location we looked into; however, information on land area for each location to convert tree cover to percentages was not readily available. We chose communities with the highest average wind speeds and lowest tree cover to recommend for wind turbine implementation.

The Griggs-Putnam Index is an empirical method used to more accurately estimate the prevailing wind speed in a specific location in a way that average wind speed data cannot4.

Energy Storage for Wind Turbines

Similar to solar-powered systems that rely on a source that is not always fully present (sun exposure during the night or on cloudy days), wind energy is an intermittent energy source.

 P = 1/2*ρ*A*v^3 where ρ is density, A is area of wind blowing through the wind farm

The amount of wind power output is proportional to the cube of wind speed. Each municipality we’ve selected in the mountainous region has an average wind speed of around 10 mph, which we’ve found is effective for wind energy implementation6. If the speed of wind was consistently around 10 mph, the wind power output would have a minimum value of around 1000 watts. However, wind is never consistent and, in fact, fluctuates; the random fluctuations in wind speed causes the power output to fluctuate, which, in return, creates issues with the system’s stability and reliability6.

Now, there are various potential solutions to mitigate wind power fluctuation, but the most optimal we’ve found is incorporating the use of ESS (Energy Storage System). The various types could be implemented into a hybrid storage system. However, many of them fail to suit wind energy in particular due to their high costs and large capacity requirements5.

Types of ESSDescriptionStorage Market Size 2021 (USD Million)
Compressed Air Energy Storage Generated electrical energy is used to compress air, which is stored in sealed caverns underground and back-produced when required via a gas turbine9. 400010
Flywheel Energy Storage SystemStore energy in rapidly spinning mechanical rotors9.297.610
Hydrogen-based Energy Storage SystemA form of chemical energy storage where electrical power is converted into hydrogen11.1472012
Superconducting Magnetic Energy StorageEnergy is stored in a magnetic field13.706
BESSBattery Energy Storage System 510014

Similar to solar-powered systems, we’ve found that the optimal type of ESS for wind power generation is BESS. This type of ESS is actually the most common utilized to mitigate wind power fluctuation. We found that this is so due to its easy implementation and small required amount to install. Though BESS is the best fit for wind energy systems, it is important to note that it still comes with its challenges; in order to counterbalance the often large fluctuations of wind power, BESS needs a large capacity (to be large in size), which causes capital costs to increase by a considerable amount15.

Other Things to Note

During our research, we’ve found another critical item to consider: the type of coupling between the turbines and storage system. Depending on whether the coupling is AC, DC, or both, more equipment will be required for hybridizing wind energy with energy storage, which will most likely increase the overall expense of the system16.

Example of Wind Energy and BESS

XCel Energy, an electric utility company, has been testing a 1 MW wind energy battery storage system that directly stores wind energy. Their system utilizes sodium sulfur battery technology –a type of BESS which has a high storage capacity, the ability to handle many charge-recharge cycles (necessary for a fluctuating renewable energy resource), and has dyanmic responses to system changes. The particular battery in use (from NGK Insulators Ltd) is made up of 20-50 kW modules and is roughly 80 tons in mass. The battery has the ability to store around 7.2 MWh of electricity.

How the System Works

When wind blows through, the battery is charged, and when wind dies down, the battery supplements the power flow. XCel claims that when the battery is fully charged, the system has the ability to power around 500 homes for seven hours17.

References
  1. WindExchange. “WINDExchange: Small Wind Guidebook.” Energy.gov, 2018, windexchange.energy.gov/small-wind-guidebook. Accessed 19 Nov. 2023.
  2.  Weather Spark. “The Typical Weather Anywhere on Earth – Weather Spark.” Weatherspark.com, 2020, weatherspark.com/. Accessed 19 Nov. 2023.
  3.  Butler, Rhett. “Deforestation Statistics for Puerto Rico.” Mongabay, 14 Aug. 2020, rainforests.mongabay.com/deforestation/archive/Puerto_Rico.htm. Accessed 19 Nov. 2023.
  4.  WindExchange. “WINDExchange: Small Wind Guidebook.” Energy.gov, 2018, windexchange.energy.gov/small-wind-guidebook. Accessed 19 Nov. 2023.
  5. “WINDExchange: Small Wind Guidebook.” http://Windexchange.energy.gov, windexchange.energy.gov/small-wind-guidebook#enough.
  6. de Siqueira, Luanna Maria Silva, and Wei Peng. “Control Strategy to Smooth Wind Power Output Using Battery Energy Storage System: A Review.” Journal of Energy Storage, vol. 35, Mar. 2021, p. 102252, https://doi.org/10.1016/j.est.2021.102252. 
  7. “Barbour, Edward, and Daniel L.F. Pottie. “Adiabatic Compressed Air Energy Storage Systems.” Elsevier EBooks, 1 Jan. 2021, www.sciencedirect.com/topics/engineering/compressed-air-energy-storage#:~:text=In%20a%20CAES%20system%2C%20electrical., https://doi.org/10.1016/b978-0-12-819723-3.00061-5. Accessed 21 Nov. 2023.
  8.  “Allied Market Research.” Allied Market Research, 2021, www.alliedmarketresearch.com/compressed-air-energy-storage-market-A31889. Accessed 21 Nov. 2023.
  9.  “Types of Energy Storage – NYSERDA.” NYSERDA, 2023, www.nyserda.ny.gov/All-Programs/Energy-Storage-Program/Energy-Storage-for-Your-Business/Types-of-Energy-Storage. Accessed 28 Nov. 2023.
  10.  Fortune Business Insights. “Flywheel Energy Storage Market Size to Hit USD 551.9 Million, at CAGR of 8.3% by 2029 | Fortune Business Insights.” GlobeNewswire News Room, Fortune Business Insights, 31 Aug. 2023, www.globenewswire.com/news-release/2023/08/31/2734922/0/en/Flywheel-Energy-Storage-Market-Size-to-Hit-USD-551-9-Million-At-CAGR-of-8-3-by-2029-Fortune-Business-Insights.html. Accessed 21 Nov. 2023.
  11. Vahid Vahidinasab, and Mahdi Habibi. “Electric Energy Storage Systems Integration in Energy Markets and Balancing Services.” Elsevier EBooks, 1 Jan. 2021, pp. 287–316, www.sciencedirect.com/topics/engineering/hydrogen-energy-storage#:~:text=Hydrogen%20energy%20storage%20is%20another,engine%20or%20a%20fuel%20cell, https://doi.org/10.1016/b978-0-12-820095-7.00019-4. Accessed 21 Nov. 2023.
  12.  “Hydrogen Energy Storage Market Size, Growth, Report 2022-2030.” Precedenceresearch.com, 2022, www.precedenceresearch.com/hydrogen-energy-storage-market#:~:text=The%20global%20hydrogen%20energy%20storage,7.1%25%20from%202022%20to%202030. Accessed 21 Nov. 2023.
  13. Vasilis Fthenakis, and Thomas Nikolakakis. “Storage Options for Photovoltaics.” Elsevier EBooks, 1 Jan. 2012, pp. 199–212, www.sciencedirect.com/topics/earth-and-planetary-sciences/magnetic-energy-storage#:~:text=Superconducting%20magnetic%20energy%20storage%20, https://doi.org/10.1016/b978-0-08-087872-0.00106-2. Accessed 21 Nov. 2023.
  14.  “LinkedIn.” Linkedin.com, 2023, www.linkedin.com/pulse/superconducting-magnetic-energy-storage-smes-systems-miu1f/. Accessed 21 Nov. 2023.
  15.  “Battery Energy Storage System Market – Global Size, Share & Industry Analysis [Latest].” MarketsandMarkets, 2023, www.marketsandmarkets.com/Market-Reports/battery-energy-storage-system-market-112809494.html#:~:text=%5B287%20Pages%20Report%5D%20The%20global,expanding%20due%20to%20several%20factors. Accessed 21 Nov. 2023.
  16. Reilly, Jim, et al. Hybrid Distributed Wind and Battery Energy Storage Systems. 2022.
  17. Wind-to-Battery Project – Xcel Energy, www.xcelenergy.com/staticfiles/xe/Corporate/Environment/wind-to-battery%20fact%20sheet.pdf.