Stocker l'énergie 2/2 Technologies

Summary

This video explores various methods of electrical energy storage, which are becoming essential due to the mismatch between supply and demand, especially with renewable sources like wind and solar. It covers mechanical storage methods like gravitational storage and compressed air, as well as advanced electrochemical solutions such as lithium-ion batteries and supercapacitors. The video also highlights hydrogen storage through electrolysis, offering a sustainable approach to manage surplus energy. Real-world examples, such as energy storage for aluminum production and the Myrte platform in Corsica, demonstrate the practical applications of these technologies.

Takeaways

• 😀 Energy storage methods are crucial to balance electricity demand and supply, especially with renewable sources like wind and solar.
• 😀 Gravitational energy storage, or pumped hydroelectric storage, stores surplus energy by pumping water to higher elevations, which can then be released to generate electricity when needed.
• 😀 The efficiency of gravitational energy storage depends on the height of the water's descent and the energy required to pump the water up.
• 😀 Compressed air energy storage (CAES) uses underground caverns to compress air, which can be decompressed to generate energy, though its current efficiency is only about 50%.
• 😀 CAES projects face challenges in terms of geological requirements and the storage of heat generated during air compression.
• 😀 Flywheel energy storage involves converting mechanical energy into rotational kinetic energy, which can be released quickly but has limited storage duration due to friction.
• 😀 Aluminum production plants use pumped hydro storage to manage high energy demands during production, ensuring grid stability by drawing from reservoirs during peak usage times.
• 😀 Mechanical storage methods are simple to implement but have limited efficiency, which restricts their dominance in energy storage solutions.
• 😀 Lithium-ion batteries, commonly used in portable devices, have a high energy density but are limited by their low maximum power output and slower charging speeds, making them unsuitable for large-scale energy storage.
• 😀 Supercapacitors have lower energy density than batteries but can charge and discharge much faster, with research into improving their performance, particularly using materials like graphene.
• 😀 Hydrogen production as an energy storage method involves using solar energy to power an electrolyzer that splits water into hydrogen and oxygen, which can later be recombined in a fuel cell to produce electricity when needed.

Q & A

What is the main challenge in managing electrical energy?

The main challenge is the mismatch between energy production and demand, especially with renewable sources like wind and solar energy, where production can fluctuate and storage is needed to balance supply and demand.

How does gravitational storage work?

Gravitational storage, also known as pumped hydro storage, stores excess energy by pumping water to a higher elevation. The energy is later released when the water falls, converting potential energy into kinetic energy, which can be turned into electricity.

What are the key factors in the efficiency of gravitational storage systems?

The efficiency of gravitational storage systems depends on the height of the water's fall and the mass of water being moved. The greater the height and mass, the more energy can be stored. However, more energy is needed to pump the water to higher elevations.

What are some examples of gravitational storage installations?

Examples of gravitational storage installations include the Art et Vin station in France, the Vianden station in Luxembourg, and a planned project in Nantes, France.

How does compressed air energy storage (CAES) work?

Compressed air energy storage works by using excess energy to compress air, which is then stored in underground caverns, often in salt formations. When energy is needed, the air is released, driving a turbine to generate electricity.

Why is compressed air storage not widely adopted?

Compressed air storage systems have a relatively low efficiency, typically around 50%, and face challenges such as the need for suitable geological formations to store the air under high pressure. Additionally, heat generated during compression complicates the process.

What is the advantage of flywheel energy storage?

Flywheel energy storage systems have the advantage of rapid response times. They can quickly store and release energy, making them suitable for applications requiring quick bursts of power, but they have limited energy storage duration due to friction losses.

How are supercapacitors different from regular batteries?

Supercapacitors store energy electrostatically and can release energy very quickly, unlike regular batteries, which store energy chemically. However, they currently have lower energy density than batteries, although research is ongoing to improve their performance.

What is the role of lithium-ion batteries in energy storage?

Lithium-ion batteries are widely used for energy storage due to their high energy density, which is ideal for compact applications like mobile devices. However, they have limited power output and charging rates, making them less suitable for large-scale energy storage.

How does hydrogen storage work in energy systems?

Hydrogen storage involves using surplus electricity to power an electrolyzer that splits water into hydrogen and oxygen. The hydrogen is stored and can later be used in a fuel cell to produce electricity when needed, with water as the only byproduct.