ESS are becoming increasingly important as the use of renewable energy sources, such as solar and wind power, becomes more widespread. These sources of energy are often intermittent, meaning that they may not always be available when needed, making energy storage a crucial component of the overall energy system. In this report, we will be discussing energy storage systems (ESS), which are devices or systems that are used to store energy for later use. 

There are many different types of ESS, each with their own advantages and disadvantages. Some common types of ESS include:

1. Chemical storage, such as batteries and hydrogen fuel cell

2. Thermal storage, such as molten salt and compressed air

3. Mechanical storage, such as pumped hydro and flywheels

4. Electrochemical storage, such as supercapacitors and redox flow batteries

Chemical storage systems, such as batteries, are some of the most widely used ESS. They can be found in a variety of applications, from small electronic devices to large-scale energy storage systems. Batteries work by storing chemical energy and then converting it into electrical energy as needed. They are relatively inexpensive and have a long life, but they can be limited in terms of the amount of energy they can store and the rate at which they can release it.

Thermal storage systems, such as molten salt and compressed air, work by storing thermal energy, which is then converted into electrical energy when needed. These systems are often used in large-scale energy storage applications, such as power plants. They can store large amounts of energy, but they can be costly to build and maintain.

Mechanical storage systems, such as pumped hydro and flywheels, work by storing mechanical energy, which is then converted into electrical energy when needed. These systems are often used in large-scale energy storage applications, such as power plants. They can store large amounts of energy, but they can be cost very high.

Electrochemical storage systems, such as supercapacitors and redox flow batteries, work by storing electrical energy in a chemical form. They are often used in applications where high power is needed, such as electric vehicles. They can store large amounts of energy, but again they can be costly to build and maintain.

In conclusion, energy storage systems (ESS) play an important role in the overall energy system by providing a way to store energy for later use. There are many different types of ESS available, each with their own advantages and disadvantages. As the use of renewable energy sources continues to increase, ESS will become even more important in ensuring a reliable and sustainable energy supply.

Sources:

"Types of Energy Storage." U.S. Department of Energy, www.energy.gov/eere/storage/types-energy-storage.

"Energy Storage Technologies." National Renewable Energy Laboratory, www.nrel.gov/learning/re-energy-storage.html.