I'm not sure about pressure cooker economy as it takes a while to heat the whole thing up to pressure, and then of course it is quick.
I've also heard on the radio that it is cheaper to heat up water for a cup of tea in a small saucepan by GAS because electricity costs about 4x more for the same amount of heat, and you always need to put more into the kettle than you need (although I put the excess into a vacuum flask).
When I cook an omelette I like it firm all over, and light brown top and bottom. I've never had any success turning it over in the pan, so I brown the top under the grille. Unfortunately it takes ages to heat up to red hot, and longer than the few minutes it takes to brown the top. Any omelette cooking ideas?