I don't believe that means the power plant or company is throwing energy away, it means how much is lost to inefficient devices or processes, including at the end user. So the more efficient LED lights throw away less energy than the older incandescent bulbs, since we know we can literally feel the heat radiate off those. And since the heat isn't the intended function of that bulb, light is, that heat is just wasted energy.

Since those Bitcoin blockchain calculations are pretty intense, they make your processor work hard. In doing so there is extra energy that literally gets wasted bc it heats up the processor, and again just like the bulb heat isn't the intended function so that heat byproduct is just wasted energy.