When European Union leaders meet for their summit in Brussels this week, energy security will continue to top the agenda. One priority is likely to be addressing concerns about Russia’s ability to provide reliable and affordable energy supplies given its current rate of investment in the natural gas sector.

While the world’s preoccupation with energy security has traditionally focused on oil, this is changing rapidly. The recent interruptions of Russian gas supply to Ukraine and western Europe focused global attention on the vulnerability of consumer countries. The European Commission has already reacted, publishing a green paper that outlines a comprehensive strategy for “secure, competitive and sustainable energy for Europe”. But there is an even broader reason for concern.