Not ready? Most electric clothes dryers, heaters, and air conditioners already use 4500 watts each. I'm sure the grid may notice an increase, the utilities will charge for the extra consumption, and upgrade accordingly. The common 200 ampere service in homes should handle another 30 amps...
A 4500W clothes dryer or heater seems like a stretch, and besides, most people don't run those with a 100% duty cycle for hours. Saying that "utilities will upgrade accordingly" hides a lot of complexity under a simple statement.
