Another advice for cooking pasta: The water does not need to be boiling the whole time. You can boil the pasta just 2 minutes, turn off the stove, close the lid and leave the pasta in the water for the rest of the time until reaching the desired cooking time, plus around one more minute. The result will be the same and you would have saved round 80% of the energy.
I don't do this, but I'm impatient so I start with scalding hot tap water. Not sure if there is any energy saving (or waste) there, since it takes at least 30 sec for hot tap water to reach max temp.
Also important for efficiency and speed is to use the least amount of water possible.