A 22.1 billion yuan investment has increased Beijing's power supply by 33 percent to 68.9 million kilo-voltage amperes (kva) to meet peak demand during the Olympic Games in August.

"Seventy more above 110 kv transformer substations were added to the power grid, bringing the total to 337," said Zhao Honglei, Beijing Municipal Electric Power Corporation spokesman, on Wednesday. "The maximum power supply was increased from 52 million kva to the current 68.9 million kva."

In September 2006, Beijing invested 22.1 billion yuan (US$3 billion) in upgrading its electricity networks. The project was completed on January 1.

"The power grid in Beijing is well equipped and able to resist heat, humidity, thunder and other extreme weather," said Zhao. "It will ensure a safe and stable electricity supply for the Olympic stadiums."

Zhao said the maximum power load during the Games is expected to hit a record 14.6 million kilowatts since the events coincide with the city's peak power demand in summer.

Electricity demand in Beijing fluctuates with climate change and the city greatly relies on power imported from other areas.

Air-conditioning use is believed to be the main cause of rising consumption during summer.