Future US and European electricity systems will depend on the harmonious evolution of low- and medium-voltage 'smart' grids with high-voltage 'super' grids (see M. Amin Nature 499, 145–147; 2013). Without care, these two developments could undermine, rather than reinforce, one another.

Both smart and super grids involve three layers (see go.nature.com/7flk7s): physical (power flows), cyber (information technology) and socio-economic (stakeholders). There are important issues in the physical layer, but the greatest tensions will emerge in the socio-economic layer as self-interested stakeholders advance local or continental interests.

Smart grids relate to local consumers becoming electricity producers themselves. This could diminish the need for high-voltage transmission grids as local power starts to serve nearby users.

Super grids will help to integrate massive renewable sources and to ensure reliability. Their development will be led by transmission companies at a time when those businesses must adapt to emerging smart grids.

If smart and super approaches are not aligned, the result will be a frailer electricity system. It is not just technologies that need to match up: policy regulations and market structures must do so too.

Smartness should not just be an issue for better local grids, but for the electricity system as a whole.