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Comment by venk12 | Hacker News Reader

Any energy expert(s) here? Can the world just run on renewables like Greenpeace is claiming? What are the significant obstacles to be overcome?

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Significant obstacles like:

- Batteries don't work at the scale of a grid. There are a few 'natural' batteries, like the water level of a hydro dam, but none for renewables.

- Sometimes it's cloudy

- Sometimes there's no wind

- The renewable grid isn't, you know, BUILT yet.

So, despite handwaving these issues away, the "baseload" capacity remains a problem which has to be addressed by something with storable energy - eg. nuclear, hydro or coal.

Do you believe we have the technology needed to safely dispose nuclear waste without affecting the environment and future generations?

Do you believe the possible threat of nuclear waste to future generations, considering our current waste management technologies, to be higher than the impact due to more CO2 generation by running electrical coal plants instead of nuclear ones? That seems a more relevant question to me.

There's no silver bullet, and pointing problems on one side only may help win arguments (maybe?) but is not so helpful when trying to find the "best" option. Which, in real life, usually means the less bad option. Warts everywhere...

Indeed, you are correct! Is there an 'impartial' governing body that has examined these two alternatives and determined the advantages and disadvantages of each? Or is there any relevant literature that focuses on simulating/evaluating these options?

Yes.

Easily, yes. It's easy and safe to dispose of, and doesn't take much space at all.

Disposing nuclear waste effectively means putting it under ~3m of water in a place where people won't mess with it.

As of 2016, France has produced 14,000 tons of nuclear waste *in its entire history*. That's about 7 normal olympic swimming pools in total volume.

We have much bigger issues with other forms of waste, nuclear waste has always just been a scaremongering tactic for the anti-nuclear crowd.

Nuclear waste is also the issue the nuclear stans like to bring up, to propagate the falsehood that it is the issue that's holding back nuclear (so they can then correctly argue that it's not that big a problem, so incorrectly claim building more nuclear is a good idea.)

Batteries work fine at scale. What they don't do is get you to 100% renewables. But hydrogen can be used for that last 5-10%, and Europe has many petawatt hours of hydrogen storage potential available in salt formations.

Sources on "they work fine at scale"?

Last I checked 4 years ago they didn't at all in terms of costs or pollution to produce/dispose of.

Natural stores energy like nuclear or hydro remain best.

Now you're moving the goal posts. If something is too expensive, it's too expensive at small scale as well as large scale.

There is no engineering reason why a grid cannot have very large amounts of batteries attached to it. If they're at the moment too expensive, that's no inherent obstacle, since battery prices have been falling rapidly, much faster than nuclear's price ever did.

> Sources on "they work fine at scale"?

Hitchen's Razor. I can dismiss your original claim without evidence, since it was presented without evidence. In other words: sources? You go first.

I suspect you are parroting studies that assume batteries are used to get to 100% renewables, then clutch their pearls at how many batteries are needed. Using batteries for that last 10% or so is just bad engineering, so those studies are strawmen.

If you have many petawatt-hours of hydrogen storage, you don't need batteries at all.

Batteries are likely going to be better for short term storage, due to their higher round trip efficiency. Hydrogen would win for long term storage (seasonal, for example) and backing up the system against rare prolonged dark-calm periods. A combination of the two storage modes could be better than either one alone. Adding additional capabilities (transmission, intermediate term storage, dispatchable demand of various kinds) can only make things cheaper.

Ignoring the high cost of batteries and the environmental harm in building them. You can eliminate pretty much an entire class of storage needs and all the cost that portains. Heck, even pumped hydro doesn't really need to exist if you have this one, practically unlimited storage system.

> Batteries don't work at the scale of a grid

https://www.irena.org/-/media/Files/IRENA/Agency/Publication...

They do. This is from 2019, there are probably better and more recent sources.

> Sometimes it's cloudy > Sometimes there's no wind

Yes, so you always use a mix. The biggest problem is when there is no sun and no wind and this happens for an extended period. At those times power will likely become a lot more expensive. And as long as we don't have seasonal storage there will always be periods in the year like that, no matter where you live unless it is close to the equator.

> The renewable grid isn't, you know, BUILT yet.

You don't need a 'renewable grid', the one we have will serve just fine.

Gamechanger: HVDC to offset day/night and seasonal cycles because it allows the transport of electricity over far larger distances. This + a relatively modest amount of storage may well be the ticket.

Batteries are expensive + needs to be replaced periodically, which is making whole setup even more expensive in the long run. Batteries are dead end for energy storage.

Batteries are emphatically not a dead end, there are many more chemistries than Lithium Ion and the life spans are approaching 6000 cycles for the best kinds which is a 20 year lifespan. Yes, they are expensive, so is everything else connected to the power grid. The cost of storing a KWh and retrieving it has been steadily dropping over the past two decades making this now a feasible method to store energy at grid scale. Even so, like everything else, it is an optimization problem, you don't want to overdesign your battery storage because the safe assumption seems to be that future tech will be even better so pacing the roll-out of such tech is a prudent approach.

Germany is running on coal. It's by far the worst example of energy vs pollution in Europe.

I think Poland might be worse actually, but yes Germany is bad.

But this coal is endorsed by Greenpeace so it's basically renewable energy.

It's renewable if Greenpeace can somehow release the CO2 from our childrens lungs.

1. Poe's law

2. Removing CO2 is basically 50% of the lungs job and they do it just fine.

That a dumb and incorrect statement.

Here is the first link when you google "greenpeace coal germany".

The level of stupidity from this and many other comments makes me wonder how many russian plants are here trying to push some agenda.

https://www.greenpeace.org/international/press-release/20429...

Russian plants are feeling accomplished ever since Germany started building gas power plants like crazy. Phasing out coal is great, phasing out nuclear before coal is as idiotic as you can get.

I'm convinced that European Greens are 50% Russian assets 50% useful idiots.

Coal used to be a biomass, therefore coal is renewable by definition.

it's 33% coal and 34% wind + solar in 2022 (https://www.destatis.de/DE/Presse/Pressemitteilungen/2023/03...).

Greenpeace want a collection of energy policies to be implemented: demand reduction, renewable power generation, no nuclear power, no fossil fuel power.

[1] is their policy from 2010. It suggests more CHP, renewable electricity generation with demand peaks balanced with hydrogen storage, improved electric public transport, rail rather than road freight, etc.

I don't have time to read it now, it is 260 pages with lots of figures.

[1] https://wayback.archive-it.org/9650/20200402044541/http://p3...

Yes, the world can run on renewables. This has become completely clear. And it's likely to end up cheaper than using nuclear, especially when you consider that today's thermal reactors cannot power the world for more than a few years before the cheap uranium runs out.

Europe's problem is that they're not well sited to use solar, compared to places closer to the equator. So heavy industry may move elsewhere. Nuclear will not change this, since solar in those best locations is very cheap.

I'm pro renewables, but I think the supply side is a significant obstacle https://www.youtube.com/watch?v=MBVmnKuBocc

I'm not going to waste time watching a video; they're very poor at efficiently transmitting information compared to text. Can you summarize the argument so I can poke holes in it?

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)

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).

>> 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/ )

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