The conversion process of compressed air energy storage

How do compressed air storage systems use energy?

The modeled compressed air storage systems use both electrical energy (to compress air and possibly to generate hydrogen) and heating energy provided by natural gas (only conventional CAES). We use three metrics to compare their energy use: heat rate, work ratio, and roundtrip exergy efficiency (storage efficiency).

What is a conventional compressed air energy storage system?

Schematic of a generic conventional compressed air energy storage (CAES) system. The prospects for the conventional CAES technology are poor in low-carbon grids [2,6–8]. Fossil fuel (typically natural gas) combustion is needed to provide heat to prevent freezing of the moisture present in the expanding air .

What is compressed air energy storage (CAES)?

Storage technologies are being developed to tackle this challenge. Compressed air energy storage (CAES) is a relatively mature technology with currently more attractive economics compared to other bulk energy storage systems capable of delivering tens of megawatts over several hours, such as pumped hydroelectric [1–3].

What are the main components of a compressed air system?

The largest component in such systems is the storage medium for the compressed air. This means that higher pressure storage enables reduced volume and higher energy density.

Can compressed air store electricity at scale?

One of the critiques of using compressed air to store electricity at scale is its low exergy density. Here, we define exergy density of the storage facility as the ratio of the delivered exergy (i.e., expansion work) to the volume of the air storage cavern.

How does a compressed air compressor work?

An attractive feature of this technology is the relative simplicity of the process—a compressor is powered by available electricity to compress air (charging), which is then stored in a chamber until the energy is needed. During discharge, the compressed air is run through a turboexpander to generate electricity back to the grid.