Many people who have ever been to Yuchai Group often noticed the modern production lines in the workshops only, but never thought there was a roof PV power generation project over their heads. With the largest-ever installed capacity in the country, the project has gone into normal operation.

When I climbed to the top of Yuchai's office building and looked down, I could not help exclaiming in surprise. The roof of every workshop was covered with myriads of dark blue poly-silicon panels which were just like blue lakes in the sun.

With an installed capacity of 30,002kW and a static investment of 330 million yuan, completed in June 2012, Yuchai's PV power generation project involves 125,000 240W poly-silicon modules. With an area of 380,000 square meters, the project was constructed on the roofs of 38 plants in 10 plant areas without using land resources.

With a designed useful life of 30 years and an average annual generating capacity of 27 million kilowatts-hour, the project uses a scheme of block generation and centralized grid connection. It actually generated 25.5 million kilowatts-hour of electricity in 2013 and 12.5 million kilowatts-hour in the first half of this year. About 87 percent of generated power is for internal use and the rest is directly transmitted to power grid.

Roof power generation and below-roof production has become a view of Yuchai. Then how many people are needed to manage such a large PV power generation project? 13! Ma Xuechen, manager of the General Management Department of Yuchai New Energy Co., Ltd., replied, taking me by surprise.

"The project will automatically start when the sun rises and shut down the sun sets to accomplish real-time full-automatic operation and full-automatic remote monitoring," said Ma.

In the monitoring room, the supervisor Liang Changjian showed me the power station's remote monitoring system. Through optical fiber, the data acquisition module and computer monitoring equipment transmit operational parameters such as the system's generating capacity and voltage as well as environmental parameters such as illumination intensity and ambient temperature to the monitoring system.

The project's primary operating expenditures are for labor, panel cleaning and other maintenance items. Use of an automatic control system has greatly reduced the project's daily operation cost.

It has been more than two years since the project went into operation. How is Yuchai's economic and social benefit from such a heavy investment? I asked Ma to do a calculation:

"The national subsidiary for the project was 189 million yuan and we raised an amount of 140 million yuan, according to the generating capacity in these two years, the charge of self-use electricity was some 12 million yuan, the charge of electricity transmitted to power grid was some 3 million yuan, so the total charge was 15 million yuan. As far as the self-raised part is concerned, we expect the project to recover the cost in 10 years and the benefit will be very considerable afterwards according to the designed life of 30 years."

"The project can save some standard coal by 10,800 tons annually, correspondingly reducing carbon dioxide emission, sulfur dioxide emission and nitric dioxide emission by some 26,924 tons, 810 tons and 405 tons respectively. The solar energy on the roofs has absorbed and reflected the vast majority of energy to make the workshops cooler and reduce use of refrigeration equipment such as air-conditioner and fan."

According to sources, the project's generating capacity accounts for around 6 percent of Yuchai's annual power consumption only. Yuchai actively initiated the project at that time because it felt it tallies with the core concept of "Green Development & Harmony Win-win". The project's success has become the superb annotation for the green concept as well as a brilliant symbol of energy conservation, emission reduction and PV buildings.

"Despite a long payback period, the project is fairly stable. We can continue to tap the potential of generating capacity. It is believed that the country will intensify support for green energy, energy conservation and emission reduction and the charge of electricity generated by new energy will increase gradually," Ma said.

The project's installed capacity has exceeded the total installed capacity of all the previous "Golden Sun" projects in Guangxi, is of great demonstrative significance for Guangxi to explore the way to improve the capacity for sustained energy supply, thoroughly push forward building energy conservation and promote BIPV, and has provided precious experience for the construction of large distributed PV power stations in the country. "According to the project's operation conditions, I feel this way: I The project has a heavy investment and a long payback period, distributed PV power generation projects are inseparable from the country's support, and timely appropriation of financial subsidies is the key to project implementation; II Modern means of technology should be taken to minimize daily operation cost; III Economic benefit should be balanced with ecological benefit with a focus on long-term development; IV A rational mechanism of electricity pricing should be worked out to make electricity price reflect input cost and ecological benefit," Ma said.

(Tong Zheng/Economic Daily)