At 11.4 cents/kWh, the USD cost of electricity to run a system 24/7 for a year equals its wattage. e.g. A CPU which draws 100 Watts will cost you $100/yr if your electricity is 11.4 cents/kWh. It's a happy coincidence for Americans since 11.4 cents/kWh is pretty close to the average price of electricity in the US (usually 10-12 cents/kWh; currently 10.4 cents/kWh). You can just look at the Wattage of a device, and put a dollar sign in front of it to see roughly how much electricity it would cost you if you ran it 24/7 for a year.
So when electricity is 3x11.4 = 34.2 cents/kWh, a 135W CPU run 24/7 for a year will cost you 3x135 = US$405/yr in electricity.
However,
we're not comparing against zero. We're comparing against another CPU which draws (nominally) 105 Watts. So the wattage delta is only 30 Watts. Meaning the
difference in electricity cost over a year between your two choices is only $30/yr in the U.S., 3x30 = $90/yr @ 34.2 cents/kWh.
And if you're not running it at max power 24/7, say it spends only 5 nights per week rendering, dropping average wattage to just 1/3 the peak, then now the difference drops to just $10/yr in the U.S., $30/yr @34.2 cents/kWh.
These CPUs cost around $500. So although the lifetime electricity cost can be on the order of the CPU cost, when comparing between two CPUs the electricity consumption difference is usually not enough to change a purchase decision. It only becomes a significant factor when you're building things like a large server or render farm. (And in that case, you're probably looking at $ per performance, rather than $ per component or $ per year.)
It's mostly mobile systems where power consumption (between choice of CPU) is a significant factor. And that's because your energy budget is constrained by your battery capacity, not because of the cost of electricity. (In fact this is the root cause of all our climate change woes. There's little incentive for an individual to save energy because the savings is peanuts on a per person basis. But multiply that by 8 billion people and it becomes a massive amount.)