A worker climbs outside an Apple store in Hong Kong, April 10, 2013. Reuters/Bobby Yip

Apple Inc. aims to build 200 megawatts of solar power projects in China and work with local suppliers to cut its carbon footprint. The announcement is Apple’s second green initiative in six months as the company seeks to repair its image after harsh criticism over pollution from the company's Chinese supply chain.

“Climate change is one of the great challenges of our time, and the time for action is now,” Apple CEO Tim Cook said in Beijing.

Apple said in April that it would build two 20 megawatts solar farms in Sichuan province, which is now complete, creating more than the total amount of electricity used by Apple’s offices and retail stores in China.

As part of Wednesday's announcement, Apple’s largest Chinese supplier, Foxconn Technology Co. Ltd., said that it will build 400 megawatts of solar energy projects by 2018, starting in Henan province. Foxconn has committed to generate as much renewable energy as its Zhengzhou factory uses in final production of the iPhone, Apple said.

The program will avoid over 20 million tons of greenhouse gas emissions in China between now and 2020 and will significantly expand the company’s clean-energy investments in China. The new projects will collectively amount to a total of 2 gigawatts worth of solar power installations for Apple's Chinese factories, according to a company statement.

According to Reuters, the iPhone maker said it would buy about $850 million worth of power from a solar farm to cut its energy bill in its home state of California in February. Other Silicon Valley giants are also moving into renewable energy, including Google, which announced a new wind power investment in Kenya this week.