The package looks at ways of moderating energy demand, increasing production in Europe including from renewable sources, and developing an internal energy market. Energy sources, suppliers and routes should be diversified to reduce the risk of supply problems, the Commission said.
The package includes moves to ensure access to gas supplies. Dependence on external suppliers such as Russia makes Europe vulnerable, and the Commission proposes a shift to a regional rather than a national approach, with a "solidarity principle" where neighbouring states would help to ensure gas supplies for households and essential social services.
Under the new law member states would also have to gain approval from the Commission on any intergovernmental agreements with non-EU countries.
A liquefied natural gas (LNG) strategy will improve access to LNG for all states as an alternative source of gas, in an attempt to end the single-source dependency of some states, the Commission said.
Finally the strategy looks at changing how buildings and industry are heated and cooled. Currently, this is 76% powered by fossil fuels, the Commission said.
The publication of the energy security package follows the climate change agreement reached in Paris in December, by "placing clean energy on an irreversible pathway and setting the scene for a global energy transition", the Commission said.
Miguel Arias Cañete, commissioner for climate action and energy, said: "After the gas crises of 2006 and 2009 that left many millions out in the cold, we said: 'Never again'. But the stress tests of 2014 showed we are still far too vulnerable to major disruption of gas supplies. And the political tensions on our borders are a sharp reminder that this problem will not just go away. Today's proposals are about a reliable, competitive and flexible system in which energy flows across borders and consumers reap the benefits. They are about standing together to protect the most vulnerable. And they are about securing our clean energy future: I can assure that our commitment to a clean energy transition is irreversible and non-negotiable."