[dredmorbius]

Solar panels do have some low-reserve raw-materials requirements. CSP (concentrated solar thermal power) rather less so, though it has higher costs and isn't as easily deployed widely (PV can be installed pretty much on any existing structure, CSP generally requires its own dedication installations).

Though really, all this says is that even under a renewables scheme, we're not going to be able to provide power at the level some have come to expect for the population we've now got (7 billion) or are projected to have (10 billion).

The bigger problem from my PoV is that the existing financial and economic systems discount the sustainability capabilities of even a partial capacity provided by renewables to the point that little if any of it gets built -- the biggest hazard I and some others (Gail Tverberg is a pretty notable leading voice, Richard Heinberg another) see is that the financial and economic systems collapse well before energy or other limits fully impose themselves.

And yes, others note that renewables as presently envisioned draw heavily on nonrenewables for fabrication and construction:

https://www.readability.com/articles/oqtyksza

http://www.countercurrents.org/adair301110.htm

The fact that providing energy needs under a renewables basis is going to be really hard doesn't make nonrenewables any better -- they're only going to work until they don't and we fall off a cliff.

What's your suggestion.

[nitrogen]

Though really, all this says is that even under a renewables scheme, we're not going to be able to provide power at the level some have come to expect for the population we've now got (7 billion) or are projected to have (10 billion).

This is best viewed as an engineering problem; those are much easier to solve than social problems.

[dredmorbius]

It's not an engineering problem to the extent that you've got populations whose very existence depends on these energy streams.

At that point, it becomes a rather pressing existential problem.

You cannot simply "engineer" more energy into existence.

Yes, there's quite a bit more energy striking Earth every day from the sun than humans use today. However it's not in forms we can utilize directly, other than simply basking in it. The most widespread process for converting sunlight into useful energy is about 1% efficient, we're already using 14% of all its productivity on the planet, and using it to replace existing fossil fuel uses would require another 21%. That's plants, and for humans to directly utilize 35% of all net primary productivity strikes me as manifestly infeasible.

Source: Jeffrey Dukes, "Burning Buried Sunshine"

http://globalecology.stanford.edu/DGE/Dukes/Dukes_ClimChange...

And the lack of an engineering solution means that this is a social problem -- that's the fundamental conflict here: deciding how to allocate scarce resources.

[nitrogen]

Well, either we find a way to give people what they want, through efficiency or new energy sources, or America keeps bombing the Middle East. And I expect viable fusion to be easier to solve than the politics of a world running out of energy.

[dredmorbius]

Bombing the Middle East is going to be producing markedly diminishing returns by and by. It's not a permanent solution.

[sliverstorm]

The fact that providing energy needs under a renewables basis is going to be really hard doesn't make nonrenewables any better -- they're only going to work until they don't and we fall off a cliff.

What's your suggestion.

My suggestion is to pick our energy sources carefully. Solar panels mean a dependence on China, which is hardly a departure from our current foreign dependence. Maybe there is no energy source that doesn't put us completely at the mercy of another nation, but who knows if that's the case? No one, because renewables are marketed as inherently endless. I'm not a civil engineer, so I don't know all the details and I can't tell you what the best system is. I defer to the actual experts on that. But I can tell you that the endlessness of renewables may be technically true, but often not at all in practice. That's all I'm getting at.

[dredmorbius]

Solar panels mean a dependence on China

If you're referring to rare-earth production, my understanding is that this is more a matter of where mining operations are considered viable and acceptable (largely on a basis of environmental impacts). The elements themselves are relatively abundant in the Earth's crust, they're simply not concentrated as other minerals have traditionally been (though we've done a rather good job of ensuring that concentrated ores no longer exist).

Materials dependence is also different from fuels dependence. In the latter case, short-term interruptions can have massive disruption effects on whole economies. Look at what possible military action in Syria is doing to current oil prices, let alone the disruptions of the 1974 and 1979 oil embargoes. Were material flows interrupted, what would be disrupted would be additional energy systems development, but existing systems would continue to function fine (modulo maintenance and retirement).

the endlessness of renewables may be technically true, but often not at all in practice.

There's a fair bit of truth to that. Many renewables technologies are dependent on specific and limited materials, or on complex technology stacks: PVs also require an extensive chip-fabrication infrastructure. Once it's established and producing it's pretty efficient, but having to build it from scratch would be a challenge.

You're touching on issues that many who are looking at future paths (generally: "collapse", "transition", or some combination / variant of these and other options) with cold, clear vision see.

My point is that whatever challenges renewables offer, they're out only hope, so if it turns out that they do have profound limitations, we'd best start getting used to that idea. If this means going back to animal power and firewood -- well, we have a rough idea of what sort of population can be supported on that technological stack. And I don't paint renewables as necessarily being sufficient for present-day (or even technologically advanced) lifestyles, though I suspect they might be able to offer that.

[sliverstorm]

My point is that whatever challenges renewables offer, they're out only hope

Ok, we're on different pages then. I don't dislike renewables. I think at least one of them is probably the way of the future. I just dislike the black-and-white way renewables vs. nonrenewables are addressed.

[dredmorbius]

I just dislike the black-and-white way renewables vs. nonrenewables are addressed.

Then do some research.

I've, literally, dedicated the past 9 months to figuring out what the hell is going on. And one way or the other, we're going to run out of fossil fuels in any practical economic sense (there will always be some coal, oil, and natural gas underground, but the ability to extract it and gain useful economic productivity from it will eventually expire).

You can quibble over whether we've got enough to last for 5 years, 50, 500, or 5000, but they will run out. Almost certainly at some point in the timespan I've just given. Very likely sooner rather than later for oil (on which we're tremendously dependent for anything involving transportation), and likely not much longer for gas and coal. And those timespans are well within the span of existing human history. Which is to say: we're facing the very probable end of industrial civilization of humans on Earth.

It's also hardly a "green" or "liberal" viewpoint: the finite nature of fossil fuels was realized quite early in the Industrial Revolution. William Stanley Jevons is often mentioned ("The Coal Question", 1865), but he was beat by 76 years by John Williams, "The Limited Quantity of Coal in Britain", 1789. More recently, M. King Hubbert (petroleum engineer), Hyman Rickover (US Navy admiral), and Colin Campbell (petroleum engineer).

It's geology, physics, and math. Not ideology.

And even if we've got reserves to last a million years, the environment can't take it. CO2, mercury, sulfur dioxide, particulates, and other pollutants from coal, oil, and gas will kill us.

We're stuck between those two prongs.

And beyond energy, there's a host of other resources which humans have done an exceptionally good job of drawing down. As if it's our job (and I could make a fair case that it has been).

And, as with any coldly rational bottom-line focused employer, once an employee has provided all the useful work they can provide you, you let them go.

That's us: humanity is very close to having worked its way out of a job. And no, the Universe doesn't offer unemployment insurance, welfare, or a pension.

Think it over. Do some research. See what conclusions you come to.

[sliverstorm]

You're so eager to defend renewables you're projecting opinions you want me to have, on me.

What I mean is I don't like how anything that is grouped into "renewables" is considered to be equally perfect. Like, "It's not fossil fuels so it's the holy grail". Nevermind that hydro backs up rivers and solar panels require rare earth metals. This sort of mindset, I figure, will hamper our ability to choose the best renewables. I'm not saying we should stick with fossil fuels.

[dredmorbius]

What I mean is I don't like how anything that is grouped into "renewables" is considered to be equally perfect.

In which case, you're projecting opinions on me which aren't correct.

In the world of energy sources available to humans, there are two classes:

Renewables which replenish given time.

Nonrenewables which don't.

For all of human existence save the past 250 years, we've depended virtually entirely on renewable resources. Which isn't to say they didn't have negative impacts on the land humans occupied. Deforestation and desertification are very common in human history and prehistory.

For the past 250 years or so we've had coal, oil, and gas. The chart looks roughly like this: https://plus.google.com/photos/104092656004159577193/albums/...

There are a handful of other nonrenewables which are sufficiently abundant that they might be able to address some of our energy needs (mostly electricity -- transportation, liquid fuels, and chemical feedstocks remain a major issue). They have some pretty tall technical challenges however. Thorium reactors are more probable, fusion rather less so: we've been unable to reach technical let alone commercial viability with 50 years' research during the period of maximum abundance.

And there's a very clear relationship between energy, economic growth, and population: http://ourfiniteworld.com/2012/08/29/the-long-term-tie-betwe...

Anyhow, as I said: list out your options. Figure out how viable they are, and what the negatives are.

A list of questions I like to keep in mind:

1. How Much Energy is Returned for the Energy Invested (EROEI)?

2. Have the claims been verified by an independent third party?

3. Can I see the alternative energy being used?

4. Can you trace it back to the original energy source?

5. Does the invention defy the Laws of Thermodynamics?

6. Does the inventor make extravagant claims?

7. Does the inventor claim zero pollution?

8. Can I see blueprints, schematics or a chemical analysis of how it works?

9. Infrastructure Requirements -- Does the energy source require a corporation to produce it? How will it be transported and used? Will it require new engines, pipelines, and filling stations? What will these cost? Who will pay for them and with what? How long will it take to build them?

From: http://www.fromthewilderness.com/free/ww3/052703_9_questions...

Have fun.