>300-600 watts per hour

Watt is a measure of energy/time. It doesn't make sense to say watts per hour.

Electricity consumption is traditionally metered per kilowatt hour, that is the amount of energy used sustained over the course of an hour.

I believe this is what the GP was referring to - the sustained usage of 300-600W over the course of an hour. Thus being very expensive to run for long periods of time.

In my area I’m charged at 16.56 pence per kilowatt hour, meaning at an average consumption rate of 450w - that television would cost me in the region of £13.41 a month to run, assuming 6hours usage per night. Which is quite expensive.

> It doesn't make sense to say watts per hour.

Perhaps, but that doesn't change the fact that Plasma TVs are generally more expensive to run than modern LCD or OLED TVs. [1]

Pioneer's 9th generation Kuro KRP-600A had an operating power consumption of 478 watts. [2]

[1] https://www.rtings.com/tv/learn/led-oled-power-consumption-a...

[2] https://www.whathifi.com/pioneer/krp-600a/specs

That was true only for the very old plasmas. Newer ones were comparable to same age LCDs.