>Electrical transmission systems are roughly 85% efficient to the consumer; together with boring old resistive electric radiators which are 100% efficient.
I'm wary of attempting comparisons of end to end efficiency, just because these aren't apple to apple comparisons. Solar panels are 20% efficient. Nuclear power can be anywhere between 60 and 90% efficient. Coal plants can be between 35 and 50% efficient. Each of these can have an economic rationale despite these differences in efficiency.. A Dyson sphere with 0.001% efficiency could be a winning value proposition. Granted, these are energy sources rather than transmission infrastructure, but the point is the same.
I would want to know about the efficiency loss from whatever primary source of energy was generated before it gets transmitted across the electrical transmission infrastructure, and I would want to know how it compares to a steam source, which could plausibly be such a thing as waste heat. If your steam is cheap or potentially even free it could conceivably win out in the final assessment, even if it has higher relative transmission losses.
Maybe this just makes your point, but solar panels being 20% efficient is about "how efficiently it converts energy from the sun into usable electricity"
All that matters is the actual power generation since there's no marginal utility of "what else we would use that space for" (unless you're consuming farmland etc for the solar panels)
Ah, but a thermal solar panel is more like 60% efficient, and it's built of glass, black spray paint and a garden hose. If the ultimate goal is to heat something with sunlight, you know which approach is the best. Several times as much area coated in special silicon stuff, or.... garden hose spray-painted black.
If the purposes are mixed, of course a photovoltaic panel can generate electricity for many purposes, while sunlight shining on a garden hose can only heat water. So it might be a more useful system, even more cost-effective, despite being much less thermally efficient.
It's the same with burning things to make heat, versus burning them for electricity and then using electric heaters.
I'm wary of attempting comparisons of end to end efficiency, just because these aren't apple to apple comparisons. Solar panels are 20% efficient. Nuclear power can be anywhere between 60 and 90% efficient. Coal plants can be between 35 and 50% efficient. Each of these can have an economic rationale despite these differences in efficiency.. A Dyson sphere with 0.001% efficiency could be a winning value proposition. Granted, these are energy sources rather than transmission infrastructure, but the point is the same.
I would want to know about the efficiency loss from whatever primary source of energy was generated before it gets transmitted across the electrical transmission infrastructure, and I would want to know how it compares to a steam source, which could plausibly be such a thing as waste heat. If your steam is cheap or potentially even free it could conceivably win out in the final assessment, even if it has higher relative transmission losses.