MOSCOW (Reuters) - Russia and China aim to wrap up a 10-year series of talks about Russian gas supplies before President Vladimir Putin visits China in May, media quoted the deputy prime minister as saying on Monday.

The Russian deputy premier, Arkady Dvorkovich, also said China is interested in alternative energy projects on the Black Sea peninsula of Crimea, annexed by Russia from Ukraine in March.

Moscow and Beijing have been involved in painstaking talks about possible Russian gas supplies to China, with price being the main obstacle to a deal.

"The gas talks are wrapping up. There is a common intention to complete this work before the Russian president's visit to China in May this year," Interfax news agency quoted Dvorkovich as saying in a meeting with Prime Minister Dmitry Medvedev.

Last week, Dvorkovich went to China as part of a Russian delegation to discuss cooperation in the energy sector.

Putin has urged Russian companies to expand their exposure to Asia as Europe's economy falters and countries there seek less dependence on energy supplies from their former Cold War foe. Europe is the key buyer of oil and gas from Russia.

Russia's top natural gas producer Gazprom plans to start supplying China with 38 billion cubic meters of gas per year - around a quarter of Russia's exports to Europe - in 2018.

Dvorkovich also said Russia and China plan to boost cooperation in oil and oil products, as well as in coal and power supplies.

Russia's top oil company Rosneft aims to triple oil supplies to China from the more than 300,000 barrels per day it sent last year.

"The key decisions have been taken, but both the Chinese partners and we have a desire to boost cooperation," Dvorkovich said, according to Interfax.

He also said China is interested in developing Crimea.

"The Chinese colleagues who are involved in alternative energy projects, are looking with interest at participating in similar projects in the Crimean republic," Dvorkovich was quoted as saying.