World's first dual-tower solar thermal plant boosts efficiency

In China's Gansu Province, two towering structures now dominate the landscape, marking a significant advancement in renewable energy.

The new facility, featuring two 650-foot-tall (200-meter) towers and an array of 30,000 mirrors arranged in concentric circles, is set to generate over 1.8 billion kilowatt-hours of electricity annually.

While photovoltaic panels are commonly associated with solar power, solar thermal or concentrated solar power (CSP) systems offer a different approach, Caliber.Az reports citing the foreign media.

CSP relies on heliostats, mirrors that reflect sunlight to a central point, heating a transfer fluid that then evaporates a working fluid to turn a turbine and generate electricity.

The world's largest solar thermal power station until now, the Ivanpah Solar Electric Generating System in the Mojave Desert, opened in 2014 with a capacity of 392 megawatts. The Noor Complex Solar Power Plant in Morocco, producing 510 megawatts, currently holds the title of the largest CSP. However, the new project in China, developed by the Three Gorges Group, represents a significant evolution in CSP technology.

The Ghazhou solar thermal energy storage project distinguishes itself by using two towers, both connected to the same steam turbine, unlike the separate heliostat fields of the Ivanpah facility. The innovative arrangement of mirrors in overlapping concentric circles allows them to follow the Sun’s path and efficiently reflect light to either tower. This design is projected to enhance efficiency by 24 per cent, according to project manager Wen Jianghong.

"The mirrors in the overlapping area can be utilized by either tower," Jianghong explained, noting that the mirrors boast a 94 per cent reflection efficiency, meaning most of the solar energy hitting them is redirected to the power-producing towers.

The nearly complete plant will also employ a molten salt method to store heat during the day, enabling continuous power generation even at night. The CSP system is expected to integrate with surrounding photovoltaic panels and wind turbines, contributing to a comprehensive clean energy initiative. This facility aims to save 1.53 million tons of carbon dioxide emissions annually.

Scheduled to come online later this year, this dual-tower solar thermal plant represents a significant leap forward in the quest for efficient and sustainable energy solutions.