Oettinger said companies with reservations about hydrualic fracturing, the controversial drilling practice dubbed fracking, should keep all options on the table.
"I estimate that Europe has the potential to secure about a tenth of our needs this way in the long term," he said Sunday.
Some countries in Eastern Europe are examining their shale natural gas potential. Other countries in Western Europe, however, have placed moratoriums on the controversial drilling practice. Shale efforts in Great Britain, meanwhile, are in their infancy.
European leaders are looking for ways to break the Russian grip on the region's energy sector. Russia meets about 20 percent of Europe's demand for gas. Oettinger in May said members of the European Union should develop stronger energy partnerships to avoid falling victim to "political and commercial blackmail."
Oettinger is a German politician aligned with Chancellor Angela Merkel.
The German government estimates its shale gas potential at between 24 trillion and 81 trillion cubic feet.