Two Chinese companies have proposed a massive, 1-gigawatt solar photovoltaic power plant in China's northwest, one that would be the worlds biggest if it's completed.

The China Technology Development Group Corp. (NSDQ: CTDC) and Qinghai New Energy Co. announced this week that they had formed an agreement with local Chinese officials to start the project, according to a report from research firm JL McGregor & Company.

The project in Qinghai's Qaidam Basin will start out in 2009 with a more modest initial goal of 30 megawatts at a cost of 1 billion Yuan ($146 million), and will combine crystalline silicon and thin-film solar panels, the firm reported. The timeline and projected cost of the entire 1-gigawatt project were not disclosed.

But if built, it would be almost twice the size of the largest solar photovoltaic power project announced so far, a 550-megawatt thin-film power plant to be built in San Luis Obispo, Calif. by OptiSolar to supply power to California utility Pacific Gas & Electric Co. (see PG&E to Buy 800MW From OptiSolar, SunPower and Can OptiSolar Make Thin-Film Dreams Real?).

Hong Kong-based China Technology Development Group entered the solar market in 2007 with a focus on manufacturing tin oxide glass plates for use as substrates for amorphous silicon thin-film solar cells. In September it announced the opening of a factory expected to build enough of the plates to supply 20 megawatts to 30 megawatts of thin-film cells by 2009.

Given China's meager installations of photovoltaic solar power plants so far, China Technology Development Group and other Chinese solar companies like Suntech Power Holdings (NYSE: STP), China Sunergy (NSDQ: CSUN) and Yingli Green Energy Holding Co. (NYSE: YGE) have so far focused on exporting products to the rest of the world (see China Pulls in Green Energy Investment).

A Worldwatch Institute report released in May said that solar photovoltaic power projects within China remain in their infancy compared to Japan, Germany and the United States, with most of the estimated 20 megawatts of generation capacity installed in 2007 being used for remote, off-grid applications.

Earlier this month, an experimental, 166-megawatt grid-connected solar photovoltaic power project started construction in the town of Chilin in southwestern China, People's Daily Online reported. That project is expected to cost 9.1 billion Yuan ($1.3 billion).