A Thought on Geothermal Energy

eclipsenow said:

Nimbyism really kicks in with ugly transmission lines that dominate the skyline

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I guess that's why no one makes a fuss about damming up rivers? I've never heard of the tree huggers having a stroke about flooding habitat?

eclipsenow said:

Siting and evaporation? Was there something else?

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That's not enough? The way you throw that off confirms to me that you're vastly underestimating the technical and political difficulties posed by the siting issue, and the expense required to resolve them.

Time will tell.

chilehed said:

I guess that's why no one makes a fuss about damming up rivers?

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They sure do! Which is why these are off-river - and do not wreck rivers.

It's why they're built faster - in 3 years instead of much longer - as they can work on both reservoirs and tunnels and power rooms all at once.

It's why there are so many more potential sites than previous papers thought. EG: As an extreme counter-example, who could forget the American National Academy of Science spanking "Wind, Water, Solar" author Jacobson for his awful overestimation of potential on-river hydro throughout America - just to get the costs of storage down? That was so outrageous it turned me off 100% renewables for years!

But these are off river.
These use 10% of the water per person compared to thermal coal plants, SAVING water.
These can have rubber balls and floating solar panels to reduce evaporation.
These are closed loop.
You pipe the water in slowly from a river nearby - I'm imagining a few miles or even further.
These can be topped up during a rainier season when the river is high?

These can even be built anywhere there's a cliff next to the ocean! Adapt them for salt water and you'll never run out of water.

They can be scaled up large in appropriate sites near big cities, or scaled down to basically oversized ponds up a hill on some farmer's property - generating him a little more income. Seriously - many farm stations in Australia are bigger than other countries. EG: Anna Station is bigger than Israel. Some of these will pay a farmer some good income, and their properties are so big they can well and truly afford the space! IF we go down this route in a PPP (Public / Private Partnership) it's likely they'll hardly ever see the dam and associated HVDC power lines.

I've never heard of the tree huggers having a stroke about flooding habitat?

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Australia has 300 TIMES the potential sites than we need, America 200 TIMES the potential sites you need. In sheer geology. Let's assume we eliminate all sites with any biodiversity concerns, negative land use or tourism or environmental appearance concerns. Say you rule out 80% of the available sites due to Nimbyism. That's not even threatening 100% renewables as it's still FORTY TIMES the off-river pumped hydro topology than you need.

Off river.
Saves 90% of the water used in coal plants.

That's not enough? The way you throw that off confirms to me that you're vastly underestimating the technical and political difficulties

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The way you're still throwing ON RIVER at me makes me wonder if you're even reading my posts properly? You strike me as a smart person curious about the world - have you been in a rush or something and speed reading this stuff?

eclipsenow said:

The way you're still throwing ON RIVER at me makes me wonder if you're even reading my posts properly?

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The way you ignored me saying it's about flooding landscape makes me think you're so in love with this idea that you're blind to the significance of the problems has.

chilehed said:

The way you ignored me saying it's about flooding landscape makes me think you're so in love with this idea that you're blind to the significance of the problems has.

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Storage = 10% the solar area required.
That little yellow dot over on the edge of California is the solar area required to power the USA if it were 100% solar power. 10% of that for ALL the storage the USA would need.
And you have 200 TIMES the topology required to get it done.
Gee - I wonder how we'll find the space?

eclipsenow said:

What are they? Frequency control?

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That can be part of it, but with any generation, you have to sync it to the cycles of the grid. With mechanical generators, once you do, the grid cycles tends to keep it synced, sort of like an old fashioned plug in electric clock. But there are also safety issues, and things like disconnects. It doesn't do for generation to put current on a line when the line is literally down. There are other issues that pertain to grid stability, which is why there have been episodes when generation has disconnected, causing blackouts, and has to carefully restored.

BTW, this pertains to all generation, not just solar and wind. My exposure was great big diesel generators, the last time was maybe 23 or 24 years ago, and there was a long procedure when the connection to the grid "locked out." I don't pretend to remember all of it.

eclipsenow said:

Nimbyism really kicks in with ugly transmission lines that dominate the skyline, but these PHES are not up in the sky.

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You have to have transmission lines due to things like line losses and conductor ampacity. The exception is distributed generation, which, as the name says, is more diffuse. There can still be issues involving upgrading the size of conductors. The whole reason we have transmission and primary distribution lines (possibly an "Americanism" with the last term) is that when you step up voltage, you decrease the amps in the conductor, which in turn decreases voltage drop.

Any boost to local economies by solar and wind are short lived. Most happens during construction. After that, you only have maintenance, which requires less personnel than during construction.

Of course there will be a bit of an artificial boom to local economies as the construction kicks in. But if we're talking the MEGA solar farms some imagine, won't they be recycling and replacing the panels on a 40 year revolving basis? (I know they're only rated for like 25 years but even if they degrade to half capacity generation over 40 years, as long as the land is cheap enough, I can't imagine an economic case for recycling them faster than that?) I imagine - depending on the size of some of the MEGA farms - that it might be more like painting the Harbour Bridge. By the time you get to one end, it's time to start all over again back at the other end. Smaller farms might get finished and sit there for 30 years before anything exciting happens. But the big ones? There will probably always be some hail or wind damage to fix, some panels going on the blink early, and replacing some that are just plain too old.

eclipsenow said:

Of course there will be a bit of an artificial boom to local economies as the construction kicks in. But if we're talking the MEGA solar farms some imagine, won't they be recycling and replacing the panels on a 40 year revolving basis? (I know they're only rated for like 25 years but even if they degrade to half capacity generation over 40 years, as long as the land is cheap enough, I can't imagine an economic case for recycling them faster than that?) I imagine - depending on the size of some of the MEGA farms - that it might be more like painting the Harbour Bridge. By the time you get to one end, it's time to start all over again back at the other end. Smaller farms might get finished and sit there for 30 years before anything exciting happens. But the big ones? There will probably always be some hail or wind damage to fix, some panels going on the blink early, and replacing some that are just plain too old.

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Haven't observed it operating that way. Suppose you install solar panels with a 40 year average life span. Most likely you have some that fail sooner and some that fail later. That would make a nice bell curve. But the thing about bell curves is that frequency starts to pick up near the "peak." So you'd likely have panel failures in dribs and drabs, then, around the 40 year mark, you have more, then tapering off. That means most replacements will be around the 40 year mark, not at a constant rate. Even then, it would be less than the number employed for installation.

Tuur said:

Haven't observed it operating that way. Suppose you install solar panels with a 40 year average life span. Most likely you have some that fail sooner and some that fail later. That would make a nice bell curve. But the thing about bell curves is that frequency starts to pick up near the "peak." So you'd likely have panel failures in dribs and drabs, then, around the 40 year mark, you have more, then tapering off. That means most replacements will be around the 40 year mark, not at a constant rate. Even then, it would be less than the number employed for installation.

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Yeah, probably. But about other services - like if a big enough solar farm also produced hydrogen or some sort of synfuel / alternative jet fuel?

No offense, but what if we had fusion power? You engineer based on what you have now, not what you hope to have.

Tuur said:

No offense, but what if we had fusion power? You engineer based on what you have now, not what you hope to have.

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No offence taken.
That's exactly my point - you engineer based on what we have now. WWS. Wind Water and Solar.
What products those energy sources manufacture and what the hypothetical long-term local economic gains might be are speculative. I happily grant this. But we have a climate crisis and an energy security crisis and a health crisis from our addiction to coal, oil and gas. That's more than enough reasons to engineer up a plan for clean energy security from WWS. If they happen to also get into producing hydrogen, synfuels, and fertilisers from those energy sources - all the better. I mean, we'll still need nitrogen fertiliser, right? And I'm not sure which way heavy long-distance freight is going to go - Tesla or hydrogen?