The system can generate up to 40,000 kilowatt-hours of electricity per day, which is equivalent to the usage of 3,000 households in a day.

(CCTV video screenshot)

The challenge for the power industry is how to shrink the gap between the peak and bottom of electricity consumption. In China, many new methods have been developed to address the problem.

The country has installed a 10-megawatt system that stores energy through compressed air in the city of Bijie in southwestern Guizhou province, the first of its kind, CCTV reported today.

The system compresses and stores air at night when the grid load is low. During peak daytime hours, it releases the high-pressure air to drive generators to generate electricity.

The system is now officially supplying electricity to the public grid after 4,000 hours of test runs, according to CCTV.

It can generate up to 40,000 kilowatt-hours of electricity per day, equivalent to the power used by 3,000 households in a day, according to the report.

In China's electricity pricing mechanism, the daytime is part of peak electricity consumption, and prices are higher relative to the night when grid loads are low. Thus, storing electricity at night and releasing it during the day becomes a business opportunity.

"At night when electricity prices are low at the bottom of the electricity consumption, we store the electricity. During the peak hours of electricity use during the day when electricity prices are relatively high, we release it. This is profitable by storing electricity at a low price and making it available at a higher price," An Hai of the National Energy Research and Development Center for Large-Scale Physical Energy Storage Technology was quoted by CCTV as saying.

The system is low-cost, long-lived, geographically independent and environmentally friendly, making it an energy storage technology that can be applied on a large scale, according to An.

The only substance it stores is air, and there is no risk of sudden explosion, in which the air pressure is medium and the risk is manageable, according to Guo Wenbin, an engineer at the Institute of Engineering Thermophysics of the Chinese Academy of Sciences.

In the field of energy storage, one of the most widely used methods has been to use batteries to store energy at night and to release it during peak electricity consumption. Electric vehicles are also seen as having this potential.

In addition to this, pumping water from low to high and using it to generate electricity during peak usage is also seen as an important way of storing energy.

China achieves experimental power generation from dry thermal rock

(CCTV video screenshot)