Natural gas extraction in Poland should grow by 10 billion cubic metres in the coming 5 years, Treasury Minister Mikolaj Budzanowski said at the 2nd Shale Science Conference in Warsaw on Wednesday. \"Today we are talking about 10 billion cubic metres of natural gas as the extraction should grow to this level in a five-year horizon,\" Budzanowski noted.  The minister reminded that shale gas extraction should be started in Poland as early as 2015. \"In 2011 the Europeans had to pay about USD 120 billion for 320 billion cubic metres of gas imported from outside the EU. The question is whether we can afford it (...) the answer is clear - we can\'t, but we can afford to invest large sums in unconventional resource exploration, especially of oil and gas,\" the treasury minister said.  Poland extracts over 4 billion cubic metres of natural gas annually. In recent years the Polish Ministry of Environment has issued over 100 unconventional gas exploration licences.