ReneSola Ltd, a China-based solar wafer producer, said it started shipments of its high-efficiency wafers and modules in June to a number of its top customers in Europe.

The company said it shipped a total of about 54.8 megawatts (mW)of its Virtus wafers, and 20 mW of modules in June.

ReneSola had unveiled its Virtus wafer in January, saying they have conversion efficiency rates of 17.5-18.2 percent, one percent higher than the industry-standard for solar cells that use multicrystalline wafers.

Monocrystalline cells, though expensive, are more efficient than multicrystallines. The most efficient silcon-based cells have an efficiency of more than 20 percent.

The company said virtus wafer production is now running at an annual capacity of 900 mW, and is to reach 1.8 gigawatts by year end, when Virtus wafer is expected to replace all its other multicrystalline wafers.

The company said it will also discontinue nearly 200 mW of monocrystalline wafer production to focus on multicrystalline wafers. It had an annual monocrystalline wafer making capacity of about 400 mW as of last year.

ReneSola's rival JinkoSolar Holding Co last month said it will target to raise the conversion efficiency rate of its monocrystalline cells to more than 18.6 percent, and 17.5 percent for multicrystalline cells.

ReneSola on Tuesday slashed its second-quarter revenue and gross profit margin view, as lower subsidies in major European markets weigh on sales and prices.

ReneSola shares, having nearly halved their value this year, closed at $4.71 on Tuesday on the New York Stock Exchange.