Scotland's University of Edinburgh on Wednesday opened a centre to research the use of carbon to retrieve oil otherwise hard to extract from reservoirs, a method which could unlock three billion barrels of trapped North Sea oil worth 190 billion pounds ($300 billion).

A number of developers of carbon capture and storage (CCS) projects have already suggested using the method, also known as enhanced oil recovery (EOR) that has been used in North America for decades, to enhance the economic viability of their plants which are expensive to finance.

Tough new limits on the maximum sulphur content of shipping fuels will come into effect in Europe at the end of the decade, after EU governments agreed on draft legislation on Wednesday.

Air pollution from marine fuels with a high sulphur content is estimated to cause 50,000 premature deaths a year in Europe, the European Parliament has said.

"This is excellent news for our health and the environment, especially in ports and coastal areas," EU Environment Commissioner Janez Potocnik said in a statement.

Over a beer or two, Danes like to tell a story that goes like this: One night the energy ministers of the countries around the North Sea got together to divide up its oil and gas wealth. The Danish minister got very drunk, but the Norwegian managed to stay sober. As a result, Norway carved out a jagged shape that included Ekofisk, which has proved to be a major field, and Denmark was left with the dregs.

The ongoing gas leak at Total's Elgin platform in the North Sea has not contaminated fish in the area with hydrocarbons, the Scottish government said on Tuesday, confirming findings made after a fish tasting test in mid-April.

Chemical analysis of fish samples collected by government research group Marine Scotland just outside the two-mile exclusion zone around the Elgin platform found no residues of oil or gas.

Britain's North Sea has the potential to lead the world in offshore wind and carbon capture and storage technology, British Prime Minister David Cameron said as over 20 companies signed a deal to turn the region into a major renewable energy hub.

Major utilities such as Britain's Scottish Power and Norway's Statoil, manufacturers ranging from Siemens to Gamesa and supply chain companies are supporting a plan to develop the offshore wind potential of the North Sea, provisionally named Norstec.

The ongoing North Sea gas leak at Total's Elgin platform has not directly contaminated the marine environment, the Scottish government said on Wednesday citing the results of tests of water and sediment.

"All data gathered to date continues to demonstrate that the effects on the marine environment of the Elgin gas leak are, so far, minimal," Scottish Environment Secretary Richard Lochhead said in a statement.

Samples collected on the edge of a two-mile exclusion zone around the evacuated platform found no traces of oil and gas pollution, the government said.

The natural gas leak at French oil group Total's Elgin platform in the North Sea is not having a major impact on the environment, the company said in a statement on Tuesday.

Total said a surveillance aircraft had spotted a sheen on the water near the platform estimated at about 30 cubic metres.

"Preliminary assessments indicate no significant impact to the environment and dispersants are not considered necessary at this stage," Total said.

The company has said it may take six months to halt the flow of gas leaking from the abandoned Elgin platform.

Legislators in the European Parliament backed plans on Thursday to limit the maximum sulfur content of shipping fuels to 0.1 percent in some cases, meaning ships would need to switch fuels or be fitted with exhaust filters.

"Urgent action is needed to stem the rapid growth in pollution from shipping, with air pollutant emissions from shipping expected to outstrip land-based emissions by 2020," Satu Hassi, a Finnish MEP who is co-drafting the measure said.