Define electricity drain? Can you post a picture of where it says that this is a requirement?
Also, I used to have an Inspiron 15 in the 3000 series... It was pretty crappy... Dual core at 2.3GHz, 4GB RAM, onboard video... Cost $600. I really wanted something else but my father refused to buy anything else at the time...
I'm actually getting better performance out of my old Latitude E6400.