this post was submitted on 16 Nov 2024

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305

Anon questions our energy sector (slrpnk.net)

submitted 7 hours ago by [email protected] to c/[email protected]

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[–] [email protected] 15 points 6 hours ago (4 children)

Sometimes the sun doesn't shine, sometimes the wind doesn't blow. Renewables are great and cheap, but they aren't a complete solution without grid level storage that doesn't really exist yet.

[–] [email protected] 2 points 3 hours ago (1 children)

Let's be clear, the only reason grid-level storage for renewables "doesn't exist" is because of a lack of education about (and especially commitment to) simple, reliable, non-battery energy storage such as gravitational potential, like the ARES project. We've been using gravitational potential storage to power our mechanisms since Huygens invented the freaking pendulum clock. There is simply no excuse other than corruption for the fact that we don't just run a couple trains up a hill when we need to store massive amounts of solar energy.

[–] [email protected] 1 points 1 hour ago* (last edited 1 hour ago)

There is simply no excuse other than corruption for the fact that we don't just run a couple trains up a hill when we need to store massive amounts of solar energy.

How about basic maths? I

Scale is a huge fucking issue. The little country of the Netherlands, where I happen to live, uses 2600 petajoule per day. So let's store 1 day of power, at 100% efficiency, using the tallest Alp (the Mont Blanc).

Let's round up to 5000 meters of elevation. We need to store 2.6e18 joules, and 1 joule is 100 grams going up 1 meter. So to power a tiny little country, we need to lift roughly 5e13 kilos up the Mont Blanc. To visualize, that's 1.7 billion 40ft shipping containers, or roughly 100 per inhabitant.

Using 555m blocks of granite, you'd need 166 million of them (9 for every person in the country). Assuming a 2% slope, you'd need to build a 250.000m long railway line. And if you lined all those blocks up, with no space in between, you'd need 3328 of those lines (which then couldn't move, because they fill the entire space between the summit and sea level).

And that's just 1 small country.

[–] [email protected] 10 points 5 hours ago

https://www.theguardian.com/environment/2024/oct/24/power-grid-battery-capacity-growth

US power grid added battery equivalent of 20 nuclear reactors in past four years

[–] [email protected] 14 points 6 hours ago* (last edited 6 hours ago) (1 children)

Thats a chicken/egg peoblem. If enough renewables are build the storage follows. In a perfect world goverments would incentivice storage but in an imperfect one problems have to occure before somebody does something to solve them. Anyway, according to lazard renewables + storage are still cheaper than NPPs.

[–] [email protected] 0 points 6 hours ago (2 children)

Imagine this (not so) hypothetical scenario:

Yellowstone or another supervolcano erupts and leads to a few years of volcanic winter, where there is much less sunshine. This has historical precedent, it has happened before, and while in and of itself it will impact a lot of people regardless of anything else, wouldn't you agree it would be better to have at least some nuclear power capacity instead of relying solely on renewables?

Sure, such a scenario is not probable, but it pays to stay safe in the case of one such event. I would say having most of our power from renewables would be best, having it supported by 10-20% or so nuclear with the possibility of increase in times of need would make our electric grids super resilient to stuff

[–] [email protected] 3 points 5 hours ago

Nature catastrophes are the top 1 danger to nuclear energy. See Fukushima.

And the real question here would be a comparison between risk of a nuclear accident event and a renewables-impacting climate event.

[–] [email protected] 6 points 5 hours ago

Yeah let me imagine a supervolcano explosion of that scale to effect global weather patterns. What do you think will happen to your reactors? No, they are not indestructable just because they can handle an earthquake of normally expected proportion.

[–] [email protected] 20 points 6 hours ago (2 children)

Solar with Battery grid storage is now cheaper than nuclear.

[–] [email protected] 4 points 5 hours ago* (last edited 5 hours ago) (2 children)

Would love to see a source for that claim. How many 9's uptime do they target? 90%, 99%

[–] [email protected] 4 points 5 hours ago* (last edited 1 hour ago) (1 children)

Uptime is calculated by kWh, I.E How many kilowatts of power you can produce for how many hours.

So it's flexible. If you have 4kw of battery, you can produce 1kw for 4hrs, or 2kw for 2hrs, 4kw for 1hr, etc.

Nuclear is steady state. If the reactor can generate 1gw, it can only generate 1gw, but for 24hrs.

So to match a 1gw nuclear plant, you need around 12gw of of storage, and ~~13gw~~ 2gw of production.

This has come up before. See this comment where I break down the most recent utility scale nuclear and solar deployments in the US. The comentor above is right, and that doesn't take into account huge strides in solar and battery tech we are currently making.

The 2 most recent reactors built in the US, the Vogtle reactors 3 and 4 in Georgia, took 14 years at 34 billion dollars. They produce 2.4GW of power together.

For comparison, a 1 GW solar/battery plant opened in nevada this year. It took 2 years from funding to finished construction, and cost 2 billion dollars.

So each 1.2GW reactor works out to be 17bil. Time to build still looks like 14 years, as both were started on the same time frame, and only one is fully online now, but we will give it a pass. You could argue it took 18 years, as that's when the first proposals for the plants were formally submitted, but I only took into account financing/build time, so let's sick with 14.

For 17bil in nuclear, you get 1.2GW production and 1.2GW "storage" for 24hrs.

So for 17bil in solar/battery, you get 4.8GW production, and 2.85gw storage for 4hrs. Having that huge storage in batteries is more flexible than nuclear, so you can provide that 2.85gw for 4 hr, or 1.425 for 8hrs, or 712MW for 16hrs. If we are kind to solar and say the sun is down for 12hrs out of every 24, that means the storage lines up with nuclear.

The solar also goes up much, much faster. I don't think a 7.5x larger solar array will take 7.5x longer to build, as it's mostly parallel action. I would expect maybe 6 years instead of 2.

So, worst case, instead of nuclear, for the same cost you can build solar+ battery farms that produces 4x the power, have the same steady baseline power as nuclear, that will take 1/2 as long to build.

[–] [email protected] 1 points 4 hours ago* (last edited 4 hours ago) (1 children)

Uptime is calculated by kWh, I.E How many kilowatts of power you can produce for how many hours.

That's stored energy. For example: a 5 MWh battery can provide 5 hours of power at 1MW. It can provide 2 hours of power, at 2.5MW. It can provide 1 hour of power, at 5MW.

The max amount of power a battery can deliver (MW), and the max amount of storage (MWh) are independant characteristics. The first is usually limited by cooling and transfo physics. The latter usually by the amount of lithium/zinc/redox of choice.

What uptime refers to is: how many hours a year, does supply match or outperform demand, compared to the number of hours a year.

So to match a 1gw nuclear plant, you need around 12gw of of storage, and 13gw of production.

This is incorrect. Under the assumption that nuclear plants are steady state, (which they aren't).

To match a 1GW nuclear plant, for one day, you need a fully charged 1GW battery, with a capacity of 24GWh.

Are you sure you understand the difference between W and Wh?

[–] [email protected] 1 points 1 hour ago* (last edited 1 hour ago)

My math assumes the sun shines for 12 hours/day, so you don't need 24 hours storage since you produce power for 12 of it.

My math is drastically off though. I ignored the 12 hrs time line when talking about generation.

Assuming that 12 hours of sun, you just need 2Gw solar production and 12Gw of battery to supply 1Gw during the day of solar, and 1Gw during the night of solar, to match a 1Gw nuclear plants output and "storage."

Seeing as those recent projects put that nuclear output at 17 bil dollars and a 14 year build timeline, and they put the solar equivalent at roughly 14 billion(2 billion for solar and 12 billion for storage) with a 2 - 6 year build timeline, nuclear cannot complete with current solar/battery tech, much less advancing solar/battery tech.

[–] [email protected] 5 points 5 hours ago (1 children)

This is old news now! Here's a link from 5 years ago. https://www.forbes.com/sites/jeffmcmahon/2019/07/01/new-solar--battery-price-crushes-fossil-fuels-buries-nuclear/

This is from last year: https://www.lazard.com/research-insights/2023-levelized-cost-of-energyplus/

As to uptime, they have the same legal requirements as all utilities.

I was pro nuke until finding out solar plus grid battery was cheaper.

[–] [email protected] 2 points 4 hours ago (1 children)

Source (1)

Later this month the LA Board of Water and Power Commissioners is expected to approve a 25-year contract that will serve 7 percent of the city's electricity demand at 1.997¢/kwh for solar energy and 1.3¢ for power from batteries.

The project is 1 GW of solar, 500MW of storage. They don't specify storage capacity (MWh). The source provides two contradicting statements towards their ability to provide stable supply: (a)

"The solar is inherently variable, and the battery is able to take a portion of that solar from that facility, the portion that’s variable, which is usually the top tend of it, take all of that, strip that off and then store it into the battery, so the facility can provide a constant output to the grid"

And (b)

The Eland Project will not rid Los Angeles of natural gas, however. The city will still depend on gas and hydro to supply its overnight power.

Source (2) researches "Levelized cost of energy", a term they define as

Comparative LCOE analysis for various generation technologies on a $/MWh basis, including sensitivities for U.S. federal tax subsidies, fuel prices, carbon pricing and cost of capital

It looks at the cost of power generation. Nowhere does it state the cost of reaching 90% uptime with renewables + battery. Or 99% uptime with renewables + battery. The document doesn't mention uptime, at all. Only generation, independant of demand.

To the best of my understanding, these sources don't support the claim that renewables + battery storage are costeffective technologies for a balanced electric grid.

[–] [email protected] 1 points 1 hour ago

It looks at the cost of power generation

Yes.

But then you added the requirement of 90% uptime which is isn't how a grid works. For example a coal generator only has 85% uptime yet your power isn't out 4 hours a day every day.

Nuclear reactors are out of service every 18-24 months for refueling. Yet you don't lose power for days because the plant has typically two reactors and the grid is designed for those outages.

So the only issue is cost per megawatt. You need 2 reactors for nuclear to be reliable. That's part of the cost. You need extra bess to be reliable. That's part of the cost.

[–] [email protected] 11 points 6 hours ago (4 children)

If the demand goes up I have some doubt, also, mining for Lithium is far from being clean, and then batteries are becoming wastes, so I doubt you would replace nuclear power with this solution

I guess in some regions it could work, but you're still depending on the weather

[–] [email protected] 1 points 4 hours ago (1 children)

you know that grid storage does not always mean "a huge battery", you can also just pump water in a higher basin oder push carts up a hill and release the potential energy when you need it...

[–] [email protected] 0 points 4 hours ago (1 children)

Pumped storage is a thing yeah. But might just as well go full hydro, if you're doing the engineering anyways.

[–] [email protected] 1 points 3 hours ago (1 children)

I feel like we're missing the part about "push carts up a hill", which involves virtually no serious engineering difficulties aside from "which hill" and "let's make sure the tracks run smoothly". See: the ARES project in Nevada

[–] [email protected] 0 points 2 hours ago* (last edited 2 hours ago) (1 children)

Yeah, that's 50MW, storing power for 15 minutes, so 20MWh. (1).

There's also a similar company: gravicity.

They're a fun academic endeavour. But if gravity provides the potential, water beats them per dollar spend. It's not even close.

So do regular batteries.

[–] [email protected] 1 points 2 hours ago* (last edited 2 hours ago) (1 children)

A fair point, but given how the best places to build solar infrastructure tend to not have easily accessible large volumes of water, I should think that economies of scale can apply if we were to put actual investment into scaling up the gravitational potential. Sure, it's not a geometric law like for kinetic energy, but greater height and greater mass are both trivial quantities to scale in places with large empty areas. I'm simply pointing out that we've never invested in that obvious possibility as a civilization. Am I missing something obvious that makes the scaling non-viable?

[–] [email protected] 0 points 2 hours ago (1 children)

Transportation of electrical power is quite efficient. I think that colocation of generation amd storage are economically rarely a technical necessity.

I can see it work in terms of national security, but then again, regular li-ion have better economics.

The biggest problem with gravitational potential is P=mgh, that is, potential energy only grows linearly in mass and height.

[–] [email protected] 2 points 2 hours ago* (last edited 2 hours ago) (1 children)

I agree with you on the linearity issue. I just feel like using its size as a criticism is invalid, given that the very source you cited pointed out that the reason it's so small is because they chose to reuse an already-disturbed site, rather than building it on 100 acres of BLM land, which I'd argue is quite admirable. The colocation point is also fair, though our water resources in the entire american west are severely limited, and will become moreso over the next 50 years. Utah's declining snowpack and the overdrawn Colorado can only cover so much. I feel like, while the GPE law is linear for both mass and height, the fact that we can scale both is a point in favor of both pumped hydro and rail storage, and rail storage can be stored virtually indefinitely, as long as it doesn't have time to rust in place. Being able to supplement the off-hours is absolutely doable with rail.

[–] [email protected] 0 points 2 hours ago (1 children)

In practice, you're usually using existing geography (historical or geographical) for height. So you're left with scaling m.

I honestly also hoped it would be a great idea. I donated to gravicity back in the day. You live and learn.

[–] [email protected] 2 points 2 hours ago (1 children)

Again, a fair point. Assuming that anyone with an idea of the meaning of "potential energy" survives the next ten years, I'd still like to see it more fully explored in the american west, but it is, unfortunately, rather a moot point for at least five years.

[–] [email protected] 1 points 2 hours ago

Ah that's politics.

I'm fine with talking polite politics. So far you seem to me like a polite and educated person.

My point of view is from EU, not US. To me US always looked like higher highs, and lower lows, in terms to a person's achievements.

To me, EU always seemed like: wear the uniform, don't stand out. No new ideas please.

I envy living in US.

[–] [email protected] 13 points 5 hours ago* (last edited 5 hours ago) (1 children)

You don't need lithium. That's just the story told to have an argument why renewables are allegedly bad for the environment.

Lithium is fine for handhelds or cars (everywhere where you need the maximum energy density). Grid level storage however doesn't care if the building houising the batteries weighs 15% more. On the contrary there are a lot of other battery materials better suited because lithium batteries also come with a lot of drawback (heat and quicker degradation being the main ones here).

PS: And the materials can also be recycled. Funnily there's always the pro-nuclear argument coming up then you can recycle waste to create new fuel rod (although it's never actually done), yet with battery tech the exact same argument is then ignored.

[–] [email protected] 0 points 4 hours ago* (last edited 4 hours ago)

Density doesn't matter much when it comes to grid scale, indeed.

What battery technologies are you thinking of? Zinc-ion? Flow batteries?

[–] [email protected] 7 points 5 hours ago

They're currently bringing sodium batteries to market (as in "the first vendor is selling them right now"). They're bulky but fairly robust IIRC and they don't need lithium.

[–] [email protected] 1 points 6 hours ago* (last edited 6 hours ago)

Yeah, lithium mining and processing is extremely toxic and destructive to the environment. On one hand, it's primarily limited to a smaller area, but on the other hand, is it sustainable long-term unless a highly efficient lithium recycling technology emerges? And yes, I know there are some startups that are trying to solve the recycling problem, some that are promising.