Earlier quoted context omitted.
Dispatchable. That's the term. Thanks. The thing is, by the time you talk about the design lifetime power output of wind in particular, and couple in the 20% figure you quote for the round trip, one has to wonder if it is worth it. It's a lot of metal (and in particular the "weirder" metals - rare-earths and the like) to smelt and move around to get a relatively small amount of power. And the increased power losses d…
There are a few people who've done calculations of the EROEI (energy returned on energy input) of various renewable energy technologies, most notably the guy who came up with the term, Charles A.S. Hall. I've had a few discussions with him on this. Wind power has a modestly high EROEI, around 18. For solar PV, his numbers are far lower -- around 2.6. The problem comes in when you account for whether there's a minimum…
If you're talking about an EROEI on wind of 18, and a 20% storage efficiency, that brings down the EROEI to 3.6. Probably more, as not all energy will pass through the storage. Still well below replacement. Or is that already factored into the EROEI? Does that include the unmetered power usage of windmills? If so: how? Does that factor in increased power-line losses, and the cost of building and maintaining those power lines? What are the details of the windmills measured? Is that real-world data, or simulations? If real-world, where?
I agree that current foodstuffs are not suitable for biodiesel. And raises food prices. But two things. One, I was talking about synthetic production. And two, that's assuming current plants. Personally, we shouldn't be looking at land-based solutions anyways. We already have space issues, at least at that scale. Look at sea-based ideas instead. Algae farming on megascales, that sort of thing. Much more efficient, much more land available, and can be situated closer to the equator.
I knew I shouldn't have just said "rare-earths and the like". I am aware that rare earths are a misnomer in general. Although... Neodymium isn't rare, but the bulk of the world's production thereof is in China. Has that energy cost been factored in? Much less the other costs? (Amount of radioactive release, etc.)
> As for synfuels: since you're converting surplus generating capacity, your marginal energy cost is nil.
Wrong. Your marginal energy cost is the cost of building and maintaining the plant and supporting infrastructure. And even just that may be less than unity overall. It may be useful, but I'd want to see the numbers.
As for the trade you mention ("Even assuming you're building capacity specific to the need, what you're trading is a non-storable, non-mobile, non-dispatchable form of energy for one which has all of those properties"), I agree partly, but the question remains: what energy input should we use? Is it worth it to build wind generators or solar power stations? Should we stick to nuclear? Or what?
Fundamentally, we currently have a couple of different energy sources. Geothermal, direct solar, indirect solar (wind, hydro), tidal, "biological solar", nuclear energy, and potentially fusion. Everything else is just energy storage. (Well, to be pedantic, so is fission and fusion, but by the time we're worrying about those running out we'll have worse issues.)
Current biological solar solutions are not exactly efficient. Your figures show direct solar isn't either. Wind is iffy for various reasons - maybe not insurmountable, but still. Geothermal is great, but only in limited areas. Same with hydro and tidal. Nuclear is great, but the political climate is rather iffy to put it mildly.