Yes, thats right, it flys around the clock, even at night! It uses solar panels to charge onboard batteries to power extremely efficient motors. It is so light it almost lifts uff the ground immediately. Under the wing are four engine pods or nacelles, each with a set of lithium polymer batteries, a 10 hp (7.5 kW) motor and a twin-bladed propeller. Over an ideal 24-hour cycle, the motors are designed to deliver a combined average of about 8 hp (6 kW). It is quite an accomplishment. There is text & videos at their site. Interesting technology.
SOURCE LINK - SOLAR IMPULSE - AROUND THE WORLD IN A SOLAR AIRPLANE