Flywheel energy storage is a type of mechanical energy storage, while pumped hydro storage, battery energy storage, and thermal energy storage are all types of electrical energy storage.

Pumped hydro storage is a versatile technology that can be used for a variety of applications, including storing excess electricity from renewable energy sources, providing backup power during grid outages, and frequency regulation.

Flywheel energy storage is a type of mechanical energy storage that can store and release energy very quickly, making it ideal for short-term, high-power applications such as frequency regulation and uninterruptible power supplies.

Battery energy storage has a high energy density, meaning that it can store a lot of energy in a small space. This makes it a good option for applications where space is limited, such as in electric vehicles.

Thermal energy storage is a type of energy storage that can store heat or cold for long periods of time. This makes it ideal for applications such as space heating and cooling, and industrial processes.

Pumped hydro storage requires a significant amount of water and a suitable topography, which limits its geographical availability.

Pumped hydro storage is the most mature and cost-effective technology for grid-scale energy storage. It is also the most widely used technology for this purpose.

Flywheel energy storage has a very fast response time, meaning that it can store and release energy very quickly. This makes it ideal for applications such as frequency regulation and uninterruptible power supplies.

Battery energy storage is the most versatile type of energy storage and is well-suited for off-grid applications. It can be used to store electricity from renewable energy sources, such as solar and wind, and provide power to homes and businesses when the grid is down.

Battery energy storage is currently more expensive than other types of energy storage. However, the cost of batteries is declining rapidly, and battery energy storage is becoming increasingly competitive.

Battery energy storage is the most suitable type of energy storage for residential applications. It is relatively inexpensive, has a long lifespan, and can be easily integrated with solar PV systems.

Thermal energy storage is a relatively low-cost technology. It is also very efficient and can store energy for long periods of time.

Thermal energy storage is the most suitable type of energy storage for industrial applications. It can be used to store heat or cold for industrial processes, such as space heating and cooling, and metalworking.

Thermal energy storage is a relatively inefficient technology. It also requires a significant amount of space, which can be a disadvantage in some applications.

Battery energy storage is the most suitable type of energy storage for transportation applications. It is relatively lightweight and compact, and it can provide a long range of travel.