The sudden surge in the popularity of electric vehicles has taken everyone by surprise – and is causing unexpected problems.

The late night hours, when offices and industries shut down, and after people go to bed and turn off their stoves, heaters and TVs, used to be low-demand times on local electricity grids – but no longer.

Millions of electric cars are now on charge through the night, and regional power grids are hitting the wall.

Brownouts and blackouts are becoming increasingly common in cities around the world as local utilities struggle to match demand. “We have always anticipated growth in energy demand, but the extent and speed of this has taken us by surprise,” admits one city power chief.

Some cities have acted swiftly and implemented high-tech smart-grid systems that dynamically balance loads, and companies providing such technologies are in the pound seats. Jacques Dubois, spokesman for global electronics firm Schneider Electric, reported that sales had never been higher. “We are really struggling to keep up with demand from almost every corner of the world.”

But most local authorities, hammered by years of recession and incessant budget cuts, have been caught in the dark – literally.

New power sources, from alternative to traditional, are being exploited – but all take time to come on stream, as do the smart-grid systems. In the meantime, consumer protest is growing as bureaucratic performance once again lags behind technological development.