GM will add backup power function to its electric vehicles

General Motors said Tuesday that it planned to equip all of its electric cars and trucks with the ability to act as backup power supplies during blackouts.

The decision to install two-way charging technology in Chevrolet, Cadillac and GMC electric cars and trucks, enabling them to power homes in an emergency, shows how carmakers are marketing the vehicles as being not just cleaner than their gasoline counterparts, but also more practical.