Tiantai Beroperasi, China Perkuat Transisi Energi Hijau

Aerial view of the Zhejiang Tiantai Pumped Storage Power Plant in Zhejiang Province, China. The 1.7 gigawatt capacity pumped storage plant has a measured drop height of 724 meters, the highest in the world for a facility of its kind. (Photo: Sun Jinbiao/China Daily)

China is operating the full-scale Zhejiang Tiantai pumped storage hydropower plant in East China. The plant has come under the spotlight for having a measured 724-meter high drop, which breaks the world record for a similar facility.

Citing China Daily, Tuesday, June 30, all power plants in Taizhou, Zhejiang Province, began to be connected to the electricity grid last week. The 1.7 gigawatt capacity project is operated by China Three Gorges Corp or CTG.

The storage-pumped hydropower plant works like a giant battery. When the electricity supply is in excess, water is pumped into the upper reservoir. When the electricity demand increases, the water is returned to the turbine to generate electricity.

In the technique of hydroelectric power generation, the height of the falling water is the difference in height between the upper reservoir and the turbine. The higher the difference, the greater the water pressure and the energy generated. In that way, the plant can produce more electricity using less water volume.

However, the high water level of up to 724 meters also presents a major challenge. The very high water pressure requires the use of high-strength materials and very precise engineering so that the plant can operate safely.

CTG said Tiantai used four reversible pump-turbine units with a capacity of 425 megawatts each. The capacity per unit is the largest in China. This project also uses a 483-meter single-stage inclined rapid pipe, which is a national record.

The plant serves to balance the electricity supply during peak loads, absorb excess electricity during low loads, regulate the frequency of the network, and serve as an emergency backup for the Zhejiang electricity system. Tiantai is expected to generate around 1.7 billion kilowatt-hours of clean electricity each year.

The project team has also mastered the core technology to build power units with a water fall height of over 700 meters and a capacity of more than 400 megawatts. In addition, this project uses 1,000 megapascal high-strength steel produced domestically, low-heat cement techniques to prevent cracks in the rock urugan dam, as well as unmanned smart construction equipment, including autonomous bulldozers.

The completion of Tiantai is part of China's strategy to increase the role of pumped storage hydropower plants in the national energy system. This technology is considered important because it is able to maintain the balance of electricity supply from solar and wind power plants whose production varies according to weather.

According to a report by the China Renewable Energy Engineering Institute, China is expected to add storage-pumping capacity of around 100 million kilowatts in the next five years. The country also aims to have a flexible capacity of 400 million kilowatts by 2035 to support a renewable energy-based electricity system.

Deputy Head of the China Renewable Energy Engineering Institute, Zhao Zenghai, said facilities like this are increasingly difficult to replace in maintaining the security of electricity grid operations amid the increasing use of renewable energy.

According to Zhao, if previously these projects served more electricity consumption centers in the east, in the future similar plants will support cross-provincial electricity distribution from new energy producing areas in the central and western regions of China.

Meanwhile, senior engineer of the State Grid Energy Research Institute, Ye Xiaoning, said that the development of pumped storage hydropower plants is no longer just pursuing large capacity. Economic efficiency and environmental sustainability factors are also a major concern.

According to Ye, plants like Tiantai will help the power grid respond quickly to load changes in the east, while stabilizing the supply of wind and solar power in the west and north so that electricity distribution to other areas is more reliable.