One cent solar dream still alive: Yingli

Yingli Solar's chief technology officer, Dengyuan Song, has big ambitions, with the company ultimately aiming for a utopian US 1 cent per kilowatt-hour.

After majoring in micro electronics in China, Prof Songessor cut his teeth in solar technology, learning from world-leading Australian solar researcher Martin Greenat his University of New South Wales' photovoltaics laboratory.

Song notes, "At the moment, PV power cost in China is double or triple conventional electricity. But just by having innovation, costs will go down quickly".

He is confident that with further R&D their already low module production costs of 53 US cents per watt, could be brought down substantially.

He believes that synergies between solar PV and the micro-electronics industry could reduce silicon costs, while ingot growth was among the upstream polysilicon measures that could continue to deliver higher performance cells, along with wafer cutting. 

"The ingot quality is directly related to the conversion efficiency of solar cells, and thus it is key factor to the cost of PV electricity. Yingli Solar developed high-performance multi silicon ingot technology by using small and uniform grains at the initial stage of solidification or using mono silicon seed layer. This technology makes improvement of the ingot quality, and thus increased solar cell efficiency more than 1 per cent," he said.

Dr Song is also optimistic about the potential for hydrogen passivation technology, which could drive efficiency gains.

"The improvement of silicon wafer quality by hydrogen passivation technology results in increasing solar cell efficiency. Therefore, we can drastically reduce that solar power cost," he said.

"The technology is to use hydrogen atoms to counter defects in silicon wafers used in making solar panels. As a consequence, poor quality silicon can be made to perform like high quality wafers. Silicon wafers account for more than half the cost of making a solar cell."

Dr Song also sees a role for new thin-film CdTe and CIGS cells which can be deposited on "flexible substrate materials".

"Thin film solar cells have a PV market share of 5 per cent for CdTe cell and 2 per cent for CIGS cell in 2013. CdTe and CIGS cells are an important part of PV technologies in the future because of its potential low cost," he said.

Dr Song – whose company's 1.4MW solar-powered hotel in Baoding features double glass PV panels and provides about 30 per cent of the building's lighting – says China's domestic solar market was going to be the main driver for growth in coming years.

"China is not balanced, 78 per cent [of electricity] is from coal but we will be seeing renewable energy more and more, they are starting to pay a lot of attention to new policies supporting solar and biomass," he said.

"Last year the government set up a feed-in tariff, like Europe, and the Chinese market is booming."

Dr Song says while ground-mounted, large-scale solar was dominating China's mix thus far, in the long term transmission costs were likely to see rooftop solar gain ascendancy in the Middle Kingdom, as evidenced by the government's rooftop installation target of 8GW compared to ground-mounted's 6GW for 2014.

"The problem in China [with ground-mounted solar plants] is the efficiency is too low. You look at the China map, it's easy to invest there [in the west] but PV needs long-term transport to the other side of the country, and is uses a lot of energy," he said.

"I think in the long term rooftop will be a lot more popular in China than grounding."