Wind energy is a plentiful clean energy source, but harnessing it at an industrial scale presents challenges, primarily due to intermittency. The inconsistency of wind—sometimes blowing weakly or not at all—leads to power fluctuations that hinder its practicality as a primary electricity source. Using energy storage technologies is the key to overcoming wind power intermittency. This article will discuss this further, examining how energy technology is used to overcome the challenges.
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Understanding Wind Energy Intermittency
An electrical grid must have a constant and reliable power source to function properly. Burning fossil fuels can provide this, making fossil fuel plants well-suited to the modern power grid. In contrast, the unpredictable nature of wind power makes it difficult to integrate directly into the grid. If we were to attempt a direct integration, it would lead to three negative impacts:
- Grid imbalance: A sudden drop in wind turbine production would mean an energy shortfall that could trigger brownouts or blackouts.
- Dispatch issues: Fossil fuel energy production can easily be dispatched to meet quick increases or decreases in demand. Because wind power is wholly dependent on wind speed at the given moment, it would be difficult for wind turbine operators to meet demand levels from moment to moment directly.
- Curtailment: When wind power production exceeds demand, a turbine must be shut down or “curtailed”. If the wind blows strongly and a turbine curtails, an opportunity to generate power is wasted.
The financial impacts of wind power increase with penetration, or the amount of demand in a region being met by wind power. For a low penetration level, the impacts are negligible. Power production is a significant cost for higher penetration levels, intermittency, and related forecasting challenges.
Studies on regions in the United States have indicated intermittency costs between $0.002 and $0.005 per kWh, with higher costs associated with penetration levels of about 20%. For comparison, the average cost of generating wind power in the US is about $0.02 to $0.06 per kWh.
Current Solutions for Wind Energy Storage
Energy storage technologies have emerged as a primary solution for addressing wind power’s intermittency issues. The current technologies in operation include batteries, pumped hydropower, and flywheels.
Batteries
According to Recharge, in November 2022, an offshore wind farm in England powered up a Tesla battery, which was reported as the largest in Europe. Located near Hull and built by Tesla, the battery can store enough energy to power around 300,000 homes for two hours. The battery was made using Megapack, Tesla’s grid-level energy storage solution, and it is managed using artificial intelligence (AI) technology.
Pumped Hydropower
Pumped hydropower storage has been used for hundreds of years and involves using excess energy to pump energy from a lower reservoir to an upper reservoir. Stored energy can then be generated by releasing water in the upper reservoir to power turbines.
Flywheels
Flywheels store access energy as kinetic energy using a low-friction rotor that spins at a high velocity. Energy can then be released using a flywheel to power a generator. Flywheels are very adorable and have a long performance life.
Wind turbine energy storage - IN 60 SECONDS
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Innovative Approaches and Emerging Technologies
While the current technologies offer significant promise, pilot projects worldwide are exploring more innovative approaches and emergency technologies. Two particularly promising approaches involve electrolysis and compressed air.
Electrolysis
One emerging approach to energy storage is using excess energy to split water into hydrogen and oxygen through the process of electrolysis. The hydrogen and oxygen can then be saved as a chemical fuel that powers a generator or vehicle. Currently, this approach has low conversion efficiency, but hydrogen, in particular, offers a much greater storage capacity than many other approaches.
Compressed air
A compressed air system stores excess energy to pressurize air or gas in an underground storage space. The stored air or gas can be converted into electricity using heat expansion to power a turbine. In March 2024, the New York Times reported on a compressed air system in Sardinia that uses carbon dioxide.
Economic and Commercial Considerations
The most significant considerations when deploying wind energy storage technology to address intermittency are economic and commercial.
Large batteries have emerged as the primary wind energy storage technology. Research has shown that these offer a weak alternative to highly dependable fossil fuel power plants. Installing the needed battery capacity is also very costly. According to a 2018 study, meeting 80% of electricity demand in the US would require 12 hours of electrical storage for the nationwide grid, costing around $2.5 trillion.
Future Outlook and Industry Trends
While there are challenges and considerations, the future does look promising for using energy storage to combat wind intermittency.
According to the American Clean Power Association, resume battery prices have decreased 82% from 2013 to 2023. The association has also noted that large-scale battery storage capacity is expected to grow from 1 gigawatt (GW) in 2019 to 98 GW in 2030.
The optimistic outlook is backed up by a recent report from McKinsey that said $5 billion will be invested in battery storage systems in 2022, a threefold increase from 2023. The report projected that the international battery storage market will double by the end of the decade. As for utility-scale battery storage, McKinsey said it would grow 29% each year for the rest of the decade.
References and Further Reading
Petersen, C. et al. Measuring the impact of wind power and intermittency. Energy Economics. https://www.sciencedirect.com/science/article/pii/S0140988323006989
Renewable Energy Research Laboratory, University of Massachusetts at Amherst. Wind Power: Capacity Factor, Intermittency and What Happens When the Wind Doesn’t Blow? [Online] Vermont Legislative Joint Fiscal Office. Available at https://ljfo.vermont.gov/assets/docs/envy/2d50be63c1/Wind-Power-Fact-Sheet.pdf
RGBSI. 6 Key Storage Technologies for Renewable Energy. [Online] Available at: https://blog.rgbsi.com/6-storage-technologies-renewable-energy
Temple, J. The $2.5 trillion reason we can’t rely on batteries to clean up the grid. [Online] MIT Technology Review. Available at: https://www.technologyreview.com/2018/07/27/141282/the-25-trillion-reason-we-cant-rely-on-batteries-to-clean-up-the-grid/
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