The intermittent nature of renewable power sources holds back the push towards greater generation and use of green energy. Wind will blow on and off, the sun shines during the day only, and drought reduces water in the dams. It makes renewable power generation unstable and unreliable. The solution is to develop higher efficiency energy storage systems, including higher capacity long-duration energy storage devices. 

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Energy Storage System 

This term is used for power conversion and storage mechanisms, including their management and control system, up to the point they connect to a grid or premises. For example, a solar energy storage system includes:

• Power conversion mechanism- Photovoltaic cells convert solar energy into electric energy
• Batteries – For energy storage
• Inverters- For drawing power to the premises
• Control panel – To manage power distribution

The ideal energy storage system should produce power efficiently, store it for the long term, and have the scalability to respond appropriately to changes in power demand. One of the biggest challenges in the push for an excellent energy storage system is how to store your energy. Applications of clean energy in high demand applications like electric vehicles require fast charging high-capacity energy storage devices.

Energy storage systems can be classified according to the type of energy the way they convert energy:

Solar Energy Storage Systems 

Solar energy systems are the most prevalent renewable energy storage systems. Photovoltaic cells convert solar energy into electric energy, which can be used immediately or stored in batteries. The size of solar panels can be varied for varying power production. The lifetime costs of solar systems are cheap compared to other energy sources.

Potential Energy Storage Systems

The concept of this type of energy storage system is that mass holds potential energy that can convert into another type of energy when it moves for a specific distance. 

Pumped Hydro systems 

Pumped hydro is the most prevalent energy storage system in the world. Hydroelectric reservoirs hold water that is released to move an electric turbine to generate electric energy. More modern pumped hydro systems use an upper and lower reservoir. Water is pumped from the lower to the upper reservoir during low demand phases and released from the upper reservoir through the turbines in high demand phases. 

Stacked Blocked Systems 

This is a conceptual system that uses concrete blocks instead of water. Concrete blocks are stacked high where they hold potential energy. They are released and their fall rotates a motor to generate electricity.

Electrochemical Energy Storage Systems 

This system uses chemical reactions to produce an electric current. Batteries are the prevalent form of electrochemical energy storage systems. They come in various types:

Lithium-ion batteries 

Li-ion batteries are the most common types of batteries largely because of their use in consumer electronics. They are rechargeable and have come in different sizes for different applications. These batteries are compact and portable.

Li-ion batteries remain the favorite for powering devices, from small devices smartphones to high demand electrical vehicles. Li-ion batteries also form the bulk of battery storage for other energy systems like solar systems. 

Flow Batteries 

These batteries are also called redox (reduction-oxidation) batteries. This battery generates power using two electrolytes, separated by an ion-exchange membrane. Flow batteries have shown promise for high power demand applications because of the flexibility of adding electrolytes for more power. 

Zinc Hybrid Batteries 

These batteries use zinc as the anode material. These batteries are also rechargeable. Zinc is more abundant and environmental-friendly than lithium, which makes it a viable alternative for mass production. 

Mechanical Energy Storage Systems 

These systems use movement to convert it to electric energy.

Wind Energy Systems

Wind energy systems use wind movement to turn wind turbines to generate energy. These systems are very intermittent and require high-capacity energy storage devices.

Flywheels 

These are mechanical devices that are wound up tightly and released to rotate at high speeds for turning electric turbines

Compressed Air Systems 

This system stores air at very high pressure, in underground storage. The air is released to turn the motors that generate electric energy. 

Thermochemical Energy Storage Systems 

This system uses chemical reactions to generate heat which generates steam to turn electric turbines. Chemicals that are commonly used in these systems are silica gel, magnesium sulfate, lithium bromide, lithium chloride, and Sodium Hydroxide. These systems achieve high efficiency and can withstand numerous charge/discharge cycles.

What Is the Future of Energy Storage Systems?

The biggest push in achieving optimal renewable energy is in energy storage devices. Power generation has become cheaper, but this needs to be accompanied by cheap, high-capacity storage devices that can use this power. 

Renewable energy will increase in the coming years, as the world tries to push towards sustainable energy solutions. Energy storage devices hold the key to higher adoption of renewable energy.  They will help improve the uptake and efficiency of these higher levels of power generation.