Driven to meet its climate commitments over the last years, China continues to focus on its solar glass production.

The country became the world’s biggest manufacturer of photovoltaic (PV) products aiming to reduce coal usage and increase renewable energy sources.

PV glass is a technology that enables the conversion of light into electricity by the means of transparent semiconductor-based photovoltaic cells.

While the PV glass demand is outpacing the production capacity, local glass manufactures rush to expand existing workshops and build new installations.

In addition, a new market trend has developed to replace traditional backboards of solar modules with another layer of PV glass to extend panel lifetime.

Following the burst of the solar glass production, Fives, an international engineering group, has supplied more than 60 annealing lehrs in China over the last 12 months.

A new contract for a 6m lehr – the widest lehr currently in China and internationally – with a production capacity of 600 tonnes per day has recently been signed by Fives Stein Metallurgical Technology (Shanghai), a Fives’ subsidiary in China, with Hebei Yingxin Glass Group.

Yingxin is a private glass manufacturer located in Shahe City, Hebei Province, which is known as the China Glass City.

Yun Pan, Managing Director of Fives Stein Metallurgical Technology (Shanghai), a subsidiary of Fives in China, said: “We have been leading technical innovations in annealing lehrs for automotive glass, ultra-thin and PV glass over the last ten years, which allowed us to have a great amount of the local market supply, including to Xinyi Glass, Kibin and now Yinxin.

"Increasing the lehr for the glass ribbon width from the current 5.2m to 6m can save energy consumption up to 10%, which leads to a decrease in production costs by up to 5%."

Continuous annealing

The annealing lehr is not sophisticated equipment, but it’s the key to slowly cooling glass to relieve internal stresses after it was formed.

Fives has proprietary expertise for the hot air continuous annealing process to accurately control the cooling curve at every point of the glass ribbon – longitudinally and transversally.

Annealing lehr key features include:

• Optimised heating to thickness and width requirements

• Up to seven transversal cooling zones for smoother control

• Specific solution for high-capacity production of ultra-thin glass

• Accurate thermal balance calculation and proportional control system

Domestic glass makers have confidence that a constant growth in the photovoltaic industry will continue bringing sound profitability in the medium and long run, with a main focus on innovations, cost effectiveness and local manufacturing.