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Comment by forty | Hacker News Reader

The main obstacle to overcome is to decrease the consumption of energy :) it's tough because people don't really care about the environment as soon as they have to even slightly change any of their habits, and the situation would require that people significantly change their habits (so I'd say we are probably screwed)

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>> Can the world just run on renewables like Greenpeace is claiming?

> The main obstacle to overcome is to decrease the consumption of energy

If we can’t produce enough power using renewables to meet current demand you cannot run the world on renewables. So “no”.

We obviously could supply much more than current demand with renewables. After all, the world is constantly being hit by 100,000 TW of sunlight, and total world primary energy demand is 18 TW.

If you are saying the currently installed renewables cannot meet current demand, why do you think additional capacity cannot be installed?

The commenter suggested that the problem with renewables is convincing people to consume less. That is not a direct replacement.

Can capacity be installed? Sure. Do we have the resources to use renewable energy immediately available to meet our current demand? No, it has to be mined, manufactured, and installed. Can we do that in a way that is economically feasible is the real question.

Of course if you look at what's immediately available, it doesn't do. How could it possibly? No one has wind and solar fields sitting around idle, just waiting to be turned on. New capacity would have to be built. That takes time (but much less time than nuclear). It takes resources, but the resources required are small compared to what industrial society as a whole consumes. And if you look at raw mass of material extracted from the ground, fossil fuels are the vast majority of mass extracted (ignoring ground water). In comparison, the metals and other materials needed for renewable sources are much less (orders of magnitude less) for a given amount of energy production.

Yeah I'm not sure why it was concluded from my comment that I was suggesting to keep the current renewable energy production at current capacity. We need to lower consumption and build more clean (or cleaner, nothing is really clean except what's not produced) energy production.

It may be a good idea to lower current consumption, but it's by no means necessary. The available renewable resource is very large. Total world rate of primary energy consumption is around 18 TW (which might correspond to 10 TW of work); the world is constantly being hit by 100,000 TW of sunlight.

You are probably right in theory, but I think all serious plans I have seen to switch to full renewable energy involved some reduction of the consumption. It's not that it's strictly necessary, but it's probably more practical in the short term at least.

I think all plans globally involve serious increases in consumption. Otherwise, one is assuming most of the world's population stays in a state of energy poverty.

I didn’t conclude that you were suggesting that we could—-quite the opposite, I posted both the original comment and yours to make the distinction. Your comment was responding to the notion that the world can run on renewables. You didn’t make the claim that it could, you made the claim that we would need to decrease consumption so it could.

So the answer is “no” at current consumption and current renewable capacity. Further consumption will only increase, so to get to a 100% renewable place, we need to account for capacity increase and build that into the equation. We cannot make moving to renewables dependent of something that will not happen.

> So the answer is “no” at current consumption and current renewable capacity

What is this "current renewable capacity" nonsense? Currently installed capacity? Current rate of construction of renewable capacity? None of those are physical constants of nature. We want more renewables, we build more. We want them faster, we build more factories.

You seem to be trying to imply there's some sort of limit that prevents renewables from being installed to replace fossil fuels. There really isn't any such limit.

You need investment to do it and to get that investment, you need a payback that encourages the investment. Without that there is a limit.

I am talking a real ROI—not based on some apocalyptic prediction of “if we don’t invest a $1 now it’s going to cost us $100 90 years from now…”. That sort of scaremongering is not going to encourage investment because the return needs to be on a smaller time scale. We need industry to see that when they put up $1000 in renewables, it’s going to result in a $5000 return vs we put $1000 in fossil fuel tech that results in $3000 in the same time frame.

What, you're objecting because an energy system to power an industrial economy is expensive? Of course it's expensive, regardless of whether it's extracting fossil fuels, fissioning atoms, or capturing sunlight or wind.

We spend something like 5% of our GDP on energy. There is a very large budget available for replacing current energy sources with new ones.

What renewables have in their favor over fossil fuels is the lack of externalized costs foisted on everyone else. Toss in those costs -- as one should do, if one is honestly looking at the cost of an energy source -- and renewables save money, and a lot of it.

You are reading much more into my comment than is what is actually there. You need industry to make renewables happen, but industry will focus where the greatest return is first. A global scale move to renewables will only happen when their are not other options with more return.

Energy orgs and their investors are looking at the shorter game…the <10 year ROI, they do not care as much about the longer game with the >50 year ROI. Frankly I bet you will not find an energy organization CEO in 2023 who truly gives a shit if their company even exists in 2073 let alone showing a profit.

So what do you do? Find that entrepreneur willing to play the long game. One name comes to mind, but now he is pretty much universally hated on HN, so god forbid we bring his name up. But…you need a nut job type like an Elon to push the envelope and be willing to bleed some money for a long time to move the needle just enough to show that there just might be a market worth exploring by others.

You touched on the resource availability but not the economic viability. Mining, manufacturing, and land—all expensive. Renewables are a great goal, but without realistic economics you will simply will not get the level of investment to get there a fast as the proponents would like.

To give a personal example—I live in a very efficient home in Florida. My electricity runs me average about $115/mo, despite running A/C almost all year round. The cheapest I can put solar on my roof to have net $0 electrical consumption costs is around $135-150/mo (with a 15 year pay off, which will be long past when I sell this home). Additionally, because of our wetter summers and some problematic installers some of my neighbors have had roof leak issues. Thanks to incorrect installations homeowners are dealing with voided roof warranty issue revealing a hidden cost of owning solar. These issues make solar an occasional barrier in real estate sales. Considering all of the I don’t see a realistic economic reason to put solar on my roof.

Land is not expensive in most parts of the world. In west Texas, for example, land contributes maybe 1-2% of the cost of a PV field.

Other resources (steel, glass, aluminum, for example) needed to build a renewable energy system capable of powering the world will be small compared to the resources otherwise used by that world industrial economy. Renewables don't require any resource that isn't required in general (some renewable sources or storage technologies do, but this is not generally true.) Those other resources would be consumed even if the world were powered by something else. So, if resource constraints prevent renewables from working, they prevent industrial society from working at all.

Home PV in the US is several times more expensive than utility scale PV, because installing PV at small scale on awkward elevated surfaces like residential roofs is a more complex problem than just laying them out on the ground (not even mounting hardware is needed now; just lay them flat. https://www.erthos.com/ )

As you’ve identified, few people will opt into a lower quality of living in the name of the greater good. The solution is to find better power generation methods, rather than force people to accept a downgrade.

Well, it's not that much about acceptance, the downgrade is being forced on people right now (via drought, ocean rise, heat, fire, and other climatic events, and all this will also cause hunger, population move and wars), and it's a much worse downgrade than what people could do volontarily to mitigate the issue.

To what degree is personal consumption driving the demand for energy?

And to what degree are industrials, workplaces or collective activities we do as part of the society?

In any case, what are the ways to reduce consumption of energy at an individual level and society as a whole?

Are there any novel ideas that are yet to be explored?

For personal consumption, I'd assume a large part of the energy used directly come from home heating/cooling and transportation (cars). Solutions exist to improve both in many cases (insulation and public transportation/biking/walking).

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