Cambridge-based GreatPoint Energy Inc. has inked a development deal with Chinese giant China Wanxiang Holdings worth $1.25 billion to build a large coal-to-gas plant in China, according to a published report, the details of which were confirmed to Mass High Tech by a GreatPoint spokesperson.

The deal, as reported in The Wall Street Journal Monday, includes a $420 million in GreatPoint by China Wanxiang Holdings. The report calls that the largest ever investment in a privately held U.S. company by a Chinese corporation. Since it was founded, GreatPoint has taken in approximately $150 million in venture backing, from investors including Advanced Technology Ventures, Kleiner Perkins Caufield & Byers, Khosla Ventures, Sustainable Development Investments, Dow Chemical Co., The AES Corp., and Suncor Energy Inc.

According to the report, the new jointly developed plant in China should be able to generate 30 billion cubic feet of natural gas per year by 2015, and reach one trillion cubic feet of natural gas each year at its peak.

GreatPoint established a $25 million pilot-scale manufacturing plant and research and development center in Somerset in 2007.

In 2009, GreatPoint investor Dow gained an option to purchase natural gas from facilities that use GreatPoint's CO2 capture and hydromethanation technology to convert coal, petroleum coke and biomass into clean natural gas.