Russia and China are closing in on a mammoth energy deal which could insure that Beijing has the fuel to run its factories and cities and Moscow has a vast new market for its natural gas empire.<br/><br/>Russian Prime Minister Vladimir Putin today wrapped up a three-day visit to the Chinese capital, during which Russia signed dozens of commercial pacts worth 3.5 billion US dollar and set the framework for a separate, multibillion-dollar agreement to build two natural gas pipelines to China from gas fields in Russia's Far East. Together, those pipelines would be capable of supplying China with 68 billion cubic meters of natural gas annually, representing a whopping 85 per cent of the gas China currently consumes. Once the energy partners agree on a final price and the pipelines are built, China could become Russia's single biggest customer for natural gas. The agreement highlights the determination of both nations to diversify their economies and seek new customers and vendors.