The electricity, smart grid and gas projects will connect energy networks, increase the security of energy supply, and contribute to sustainable development, the Commission said.
"The Energy Union strategy has at its centre the transition to a low-carbon, and secure and competitive economy. Properly interconnected electricity lines and gas pipelines form the backbone of an integrated European energy market," it said.
Investing in sustainable and renewable energy sources will speed up the EU's move towards low carbon technologies, the Commission said.
Of the 18 projects selected for funding, seven are in the electricity sector and receiving €176m in support, 10 in the gas sector, with €228m in funding, and one for smart grid with €40m in support. Five relate to construction works and 13 to studies, the Commission said.
In the electricity sector, a €40.25m grant will support implementation of the preparation phase of Germany's largest energy infrastructure project, the SuedLink project. 700 kilometres of high voltage cables due to be laid underground to create a link between the wind power generated in the north and consumers in the south of Germany.
Other projects include a €90m grant for a compressed air energy storage project in Larne, Northern Ireland, a €102m off shore liquid natural gas terminal in Croatia and a smart grid project to make the electricity transmission grid in Slovenia and Croatia more efficient.
The money for the projects comes from the Connecting Europe Facility (CEF), an EU funding support programme for infrastructure that has allocated a total of €5.35 billion to trans-European energy infrastructure for the period 2014-2020.
Commissioner for climate action and energy Miguel Arias Cañete said: "This is another milestone in the setup of a cleaner, more competitive European energy market. An energy infrastructure which is fit for purpose is essential for renewables to thrive. Thanks to this upgrade, the proposals in the Clean Energy for All Europeans package are even closer to become a reality. The EU is demonstrating its commitment to delivering cheaper, more sustainable and secure energy to European consumers."