Savings electricity when cooking pasta

I didn't make our dinner on time one day and I started preparing pasta. I brought it to boil and it probably was boiling for about 5 min when we had to leave. I had to choice, but turn off the stove, close the lead, and leave. We came back an hour later and pasta was ready! So, instead of boiling it and using the stove for 30 min, I only did it for about 5 min :) That was a nice discovery!