[zamfi]

This is cute. But the conclusion is wrong — we can actually generate as much energy as we are currently using directly from sunlight.

It’s not trivial — costs $1X trillions, covers lots of land (a 300-mile square!) and will take a long time. But then, we have more paved roads than we would need land covered by solar farms, so it’s not a completely ridiculous amount of space.

We don’t necessarily need to sacrifice lifestyle to use energy sustainably. We just need to stop burning fossil fuels pumped/mined from underground.

[bigato]

You are ignoring the concept of EROEI - Energy Return Over Energy Investment. Basically, how much energy you need to use to produce additional energy. Or, as the comics put it, how many slaves you need to produce additional slaves. The solar farms also require maintenance and ongoing replacement. Their EROEI will never be as high as fossil fuels were when we started mining them, which allowed us to bootstrap the industrial era. We will never have such easy energy from solar alone due to physical limits on the technology. Our economy will be fundamentally affected by this change in paradigm. Even if we use the remaining fossil fuels to bootstrap solar farms, over time the EROEI will revert to solar’s, because fossil is increasingly costlier to extract.

Another way to understand EROEI is, given a solar panel system (including batteries, circuits, etc) typical lifespan of say, thirty years, how many other systems equal to this would you be able to build with the resulting e energy during those 30 years? It’s improving, but if you also account for the maintenance and required labor to keep it working, it’s still looking really bad when compared to the output we had from fossil until a few decades ago.

For more detailed information on EROEI: https://forum.earlyretirementextreme.com/viewtopic.php?f=3&t...

[zamfi]

I did not mention this because it bears more on how much energy infrastructure is required to build more energy infrastructure rather than to maintain our energy-hungry lifestyle.

EROEI is much harder to calculate for solar, wind, battery, etc. than for literal mining from the ground, but it seems like we’re around 10 for current utility-scale solar and hydro pumped storage.

That said, there are a lot of studies presenting extremes either way, usually funded by those who would benefit by the real number falling at such an extreme, so who knows.

Also, for those interested, the Wikipedia article on EROEI is actually good resource: https://en.m.wikipedia.org/wiki/Energy_returned_on_energy_in...

Nothing will ever beat the EROEI of oil spilling out of the ground ready-to-burn, but it’s also not a given that we need that to bootstrap industrial civilization.

[anonymous5133]

If it was such a great investment, wouldn't everyone be running to install it more or less? I live in Southern California (prime location for solar) and so far by my calculations, it does not make economic sense to install the panels. The economics are better if you just assume you have to pay for the panels and exclude labor, installation etc.

[Lazare]

Pumping a barrel of oil out of the ground costs about $10 in Saudi Arabia, and gives about 1600 kWh. Electricity generally costs around $0.10 to $0.25 per kWH, so if you do the math, you can see that's just enormously profitable.

Renewable energy cannot compete directly with that. For some rough numbers, you'd expect about 150 hours of usable sunshine a month (depending where you are), so to generate a barrel of oil worth of power per month, you'd need around 10 kW of solar panels, which will cost around ....maybe $35,000 to build. (Then add a few more $k for batteries, controllers, whatever...)

These numbers are super rough, and vary a lot, but just as a general order of magnitude thing, obviously it's better to pay $10 to pump a barrel of oil out of the ground every month than it is to pay $35-40k upfront to build a solar system that generates the same power; it'd take centuries for the solar system to even break even (and it's only going to last decades).

BUT. We're obviously running out of oil in general, and cheap oil in particular, and the cost of solar power is dropping fast. And also, while it would be extremely expensive (today, at least) to switch to solar and other renewables for everything, it's a thing we can do. And by the time we really will have to do it, it may not even be that expensive. And if you factor in the impact of carbon, the numbers start to look more even.

> If it was such a great investment, wouldn't everyone be running to install it more or less?

A lot of solar is being installed; for a variety of reasons domestic rooftop installations don't tend to make a lot of sense (you didn't have a coal power plant driving a steam turbine in your basement either), but that doesn't mean all solar is un-economical.

But no, it's not an amazing investment yet. But it is feasible. The comic essentially suggested that we're squandering our only chance to live beyond the power of human muscles, and that's far from true. And given the cost curve on solar panels, it's not even clear we're being too slow to make the switch.

[ZeroGravitas]

Half that energy will be lost in conversion to electricity, more if used to move a vehicle.

And recent PPAs for solar in that region are closer to 2 cents, which puts then roughly on par and the prices are still moving, in opposite directions. And if you have the sunshine but not the oil then it becomes a no brainer, why rely on another country with a history of manipulating prices to maximise their profit when you can generate your own electricity.

[ZeroGravitas]

It is a great investment and people are installing crazy amounts of it around the world.

However on an individual scale, market externalities mean that individual choices often lead to inefficient outcomes because the true cost is not borne by the person making the choice.

This is almost certainly the case when you decide that solar doesn't make sense for you economically.

[candiodari]

Meaning half the time taxpayers are paying for the installation and/or maintenance of those solar panels.

Ironically it's now flipping around. Governments have realized that in many locales, from Australia to the Netherlands and Belgium that if richer people were to cut them out by cutting the grid connection they'd be thoroughly screwed, and because the electricity prices that would have to be charged ... mostly to apartment renters in large cities would be a lot more than they pay now (the grid is 50%-80% of electricity cost, so if 20% of people outside of cities disconnect that same cost now has to increase by 25%. If it ever gets to 50% it doubles. Grid costs are mostly paying off the loans used to build the grid so they don't go down much because someone doesn't use some part of it. So that means now governments are running scared and introducing measures to make private solar panels artificially ... expensive. Yes, really.

In .au this has more-or-less changed the calculation to "it's about a neutral investment if you do it, assuming conservative panel lifespan. If you can disconnect from the grid, however ... definitely worth it. In the outback, there's no alternative". Varies by locale, as local councils have a lot of policies that matter too.

https://www.pv-magazine.com/2017/08/23/australia-aemc-shies-...

Solar might make living in cities quite a bit more expensive, especially in the places were already a lot of poor people live.

[ZeroGravitas]

That's a real interesting grab bag of reasons you don't like solar.

You want to help the urban poor and stop the rich taking advantage but you don't like government intervention or taxes. Must be tough coming up with solutions that you actually would accept when you place those kind of constraints on yourself.

Me personally, I'd use progressive carbon taxes and mostly let the power of the free market sort it out. But I guess that involves taxpayers paying for it, which I guess is now considered bad somehow? Like the military and police and schools and courts and half of modern civilization and all that terrible stuff that taxpayers pay for.