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Comment by monero-xmr | Hacker News Reader

I am still very confused how power will be generated cleanly on cloudy, no-wind days with solar and wind. I am hopeful that hydrogen can be generated in the desert and moved by hydrogen-truck. Or grid-scale batteries actually exist someday. But if we write off nuclear, a lot of coal and natural gas will be burned.

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> I am still very confused how power will be generated cleanly on cloudy, no-wind days with solar and wind.

You are making it harder by adding that "cleanly" requirement, because the simple answer is going to be "natural gas". Unlike coal or nuclear, natural gas power plants are fast to start and stop (hydroelectric is even faster, but depends on favorable geography), so they can be left powered down (using no fuel) until they're necessary; and both overbuilding wind and solar, and spreading them over a wider area, can reduce the amount of time where that natural gas (or hydroelectric) backup is necessary.

By requiring a perfect solution (100% clean), you are excluding the 90% solution which is already possible, and which can be incrementally enhanced to get closer and closer to that 100% goal (by adding more wind and solar, by strengthening the interconnections so the generation is spread over a wider area, by sprinkling a bit of storage like batteries or reversible hydroelectric, and even by dynamically reducing consumption when there's a generation shortage).

Reversible hydro is actually pretty possible in much of the world, particularly the US, because all you need is something bowl-shaped at a high elevation. Pumped hydro for the most part needs storage measured in hours or days, and something like the size of Lake Mead behind Hoover Dam is overkill.

It's also more advantageous than regular hydro, because it does not need to be in the path of flowing water, so you avoid issues with silting up, lack of suitable locations, it's much less environmentally destructive, etc.

funded by backdoor taxes if texas is any indication. Prop 7 passed, which is basically just shifting the cost of grid reliability from the energy companies to the tax payers. So now you get to pay top dollar for the energy which is 50%+ carbon sources, while also paying to keep the plants operating from the general budget.

Its like a wet dream for those energy traders.

https://ballotpedia.org/Texas_Proposition_7,_Creation_of_Sta...

The problem with this 90% solution is that the more renewables are added, the more natural gas capacity is required to cover the capacity. Good problem for the natural gas industry.

Going clean with nuclear isn’t cheap right now, and it shouldn’t be. It wasn’t at the start of renewables when solar was expensive.

Cheap, reliable, clean; pick two.

> The problem with this 90% solution is that the more renewables are added, the more natural gas capacity is required to cover the capacity.

That can be the case only if the demand also increases. If the demand stays the same, adding more wind and solar can only decrease how much the natural gas power plants are used, and the required capacity (that is, how much they can produce at full power) either stays the same or decreases (if the newly added wind and solar are non-correlated enough to reduce the chance of all of them "going dark" at the same time).

or if existing plants shut down, for example coal and nuclear plants

they are in fact shutting down in many cases because they can't compete with renewables, and the result is that more grid-scale storage or peaker capacity (or demand response!) is needed

but this is a good kind of problem to have, if you replace 900 megawatts (produced) of coal with 400 megawatts (produced, not nameplate) of solar and 500 megawatts of gas, you've still cut carbon emissions by two thirds, and lowered electricity prices at the same time

There already is a massive amount of natural gas generating capacity. But if this capacity is used one tenth as much as it is currently used it will only use one tenth as much natural gas and will last much longer.

Indeed, and EV's batteries will become more and more significant ( https://en.wikipedia.org/wiki/Vehicle-to-grid ), as will the clean backup provided by green hydrogen (obtained thanks to electricity overproduced by renewables, then fed to turbo-alternators during periods of insufficient production).

It’s possible to build mostly renewable grids today with existing technology without nuclear. For example Marin Clean Energy generates over 90% of its energy from carbon free sources [1].

Storage and batteries are the key. Although lithium ion has limitations in the use case of long term discharge and storage, new chemistries are becoming commercially available that are appropriate for grid scale power. Iron Air batteries are made out of cheap, common materials, can discharge for up to 100 hours and can store power for long periods of time. Form Energy is building a plant in West Virginia that will produce these batteries and will open in 2024 [2].

Renewables are getting increasingly cheaper. Storage is increasingly more available. The writing is on the wall. Renewables are going to win out and it’s going to happen much sooner than conventional wisdom says.

[1] https://www.mcecleanenergy.org/wp-content/uploads/2021/11/20...

[2] https://www.reuters.com/business/energy/form-energy-build-lo...

The thing about cloudy no wind days is:

1. These are conditions that don't coincidence as often as one would think

2. If they do happen at the same time they are limited to certain places

Now the only thing you need to have your solar and wind installations not in one place and make sure it is unlikely enough to have all of them inoperational at once.

If you have the proper energy storage and a big enough grid that can balance itself this is totally doable.

Deserts don't tend to have much water, so where do you expect to get the hydrogen from? Getting water to the desert takes a pile of energy as it is, and typically once it gets there people want to turn it into plants.

you can use the hydrogen an arbitrarily large number of times once you get it there, and the amount of water needed is so small that this is not a major part of the cost of a grid-scale storage system system even if you have to truck it in, which you don't because even deserts have groundwater

please do the math instead of posting random bullshit without respect to whether it's true or not

specifically hydrogen is 142 MJ/kg https://en.m.wikipedia.org/wiki/Energy_density and is 1/9 of water by mass, so each kg of water you drill, truck in, or collect from cisterns can store 15.8 MJ as hydrogen. a square meter of 21% efficient pv panel produces 210 watts nameplate, or 52 watts derating for the 25% capacity factor typical for deserts. that is 4.5 MJ per day. the water needed to store the panel's daily production weighs much less than the panel itself and is therefore much cheaper to truck in

obviously it would be stupid to truck it back out again unless you decided to do your grid-scale storage somewhere else

Deserts all have way more humidity than you could ever need for your hydrogen production. Extracting hydrogen from atmospheric water vapor is a win because it is cleaner than ground water, and has already been vaporized.

Why would you move the hydrogen? It would be generated near a storage cavern, stored there, then brought up and burned in turbines there.

Also, moving hydrogen by truck is a nonstarter. Pipelines are much better.

It's never 'not windy' everywhere, plus gravity batteries can store power for days/weeks.

Geothermal is also an 'always on' renewable.

If it was this easy, gravity batteries and geothermal would be everywhere and widely used, but they remain niche.

Because there are currently cheaper options. Those are last mile, high hanging fruit solutions.

gravity batteries and geothermal are too expensive to be competitive, except in the niches of pumped hydro, district heating, very polar regions, and stranded assets from before pv and wind got so cheap

Incidentally, the only viable gravity batteries known today are pumped hydro reservoirs. On the up side, they only need a hill. On the down side, they need a hill.

(Gravity Vault, BTW, is 100% scam.)

Suspending weights from ocean platforms (e.g. scrapped supertankers), for flat places with deep sea nearby, should be a viable alternative, but it has not been done yet. Deep cave systems are another, either draining water into them or (for those below the water table) pumping air in. There are a lot of deep caves.

Is it possible to transport wind / solar energy across the country via high powered transmission lines?

No, because of physics you lose more power the longer distance it travels. It is also very expensive and difficult to build a network that can move power great distances to where it's needed given how dense the areas that need it are (major cities).

You can certainly get it to places closer, then shift those areas' power to farther away places, etc.

China has a large network of HVDC lines. Unfortunately, due to how the Chinese power market works, they're mostly underutilized, even in times of high power stress.

Sun Cable, formerly known as PowerLink, is an ambitious idea that involves sending solar power via an undersea cable 4,200 kilometers (2,610 miles) from Darwin, Australia, to Singapore.

https://en.wikipedia.org/wiki/Australia-Asia_Power_Link

Yes, and it's already done today; for instance, in Brazil these high power transmission lines transport wind power from the northeast region (which has lots of wind due to favorable geography) to the southeast region (where most of the electricity consumption is). The total distance is on the order of 2000 km.

(A fun fact: many of these high power transmission lines were originally to send power from the hydroelectric power plants in the southeast region to the water-starved northeast region. With the rapid expansion of wind power in the northeast region, the usual direction of the flow has reversed, and it's not uncommon for that wind power to provide over a quarter of the power for the whole country.)

Genuinely curious - why is wind power being cancelled in the North East because it isn't cost competitive, if it's so easy to do?

https://apnews.com/article/offshore-wind-orsted-cancellation...

you're confusing the northeast of brazil, which is what cesar was talking about, with the northeast of the usa

these are not just in different countries but in vastly different climates in different hemispheres

the exact page you linked in your comment literally answers your question: 'due to problems with supply chains, higher interest rates and a failure to obtain the amount of tax credits the company wanted. ... High inflation, supply chain disruptions and the rising cost of capital and building materials are making projects more expensive while developers are trying to get the first large U.S. offshore wind farms opened.'

maybe you should have read it

please don't post random bullshit without respect to whether it's true or not

It’s strange because wind is supposedly overwhelmingly cheaper and better, yet even with tons of government subsidies and political will behind it, it still can’t be built. Wouldn’t something truly more cost effective be easy to build because it’s cheaper? Clearly something doesn’t add up.

> It’s strange because wind is supposedly overwhelmingly cheaper and better

There's two kinds of wind power: onshore and offshore. Their costs are different, with onshore being cheaper. The ones in Brazil are all onshore, while the one in the article you linked to is offshore. In the USA, offshore is even more complicated because of the Jones Act (it needs specialized ships to transport and erect the structures, while onshore needs only common cranes).

obviously enough, numerous projects that are profitable when you can finance them at 1% become unprofitable when you have to finance them at 6%, particularly when you're competing with incumbent assets financed at 1%

https://fred.stlouisfed.org/series/FEDFUNDS

feb 02022, 0.08% interest. since august, 5.33%

nothing is easy to build in the usa; it's halfway to being zimbabwe

Because the Jones Act of 1920 prevents use of the existing European installation ships so they have to start from scratch in uncompetitive American shipyards.

https://spectrumlocalnews.com/nc/charlotte/news/2023/04/03/t...

https://www.cato.org/policy-analysis/rust-buckets-how-jones-...

this is just one of many factors, and one that was understood by oersted when they originally started the project; the article mentions others that are more relevant

in particular, you should expect to see many, many cancelled projects across the entire economy with the interest rate hikes the usa put in place

obviously none of this is relevant to brazil

There are mild externalities assumed and feared about offshore wind, despite it being pretty good in a multitude of ways. States are playing a dumb game, because we would be better off if there was lots of offshore wind, but each state individually is better off having offshore wind SOMEWHERE ELSE.

For example, here in maine, our premier engineering school has spent two decades now being a premier wind energy investment and research institution, and we have minted hundreds and hundreds of trained people into the field, yet our Democrat governor still decided to sign a bill that bans offshore wind, something that Orono has explicitly invested into for years.

Our state desperately needs new generation to bring power costs down, but there's no real incentive for anyone to do so (why build new supply to bring down your own revenue?) and apparently the state government has zero interest to help itself there.

Ignore the sibling comment, it is definitely possible, typically via HVDC transmission. With 3% losses per 1000km, HVDC transmission of variable renewable energy is absolutely part of our future energy systems.

Wind is especially well suited to this - to a certain extent it's always windy SOMEWHERE whereas with solar you ain't generating any at night, no matter what.

> whereas with solar you ain't generating any at night, no matter what.

Nitpicking: that's only the case for photovoltaics. Solar thermal can store the heat for a while, and keep generating even after the sun goes down.

solar thermal is dead tho

just like other thermal power plants, it's too expensive to compete with pv and wind

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