[upsuper]

Every time I saw this kind of discussions, my first question is, what happens when sun is not shining? Like in the night or when it's very cloudy?

In many places in Australia, we have so many solar panels installed that's enough to power everything in the day time, but when the sun sets, coal still has to be burnt regardless.

I'm quite skeptical to grid-scale battery projects. Every such project has a total capacity of like 2hrs, making them only useful at some short peak time in the day, rather than overnight or over a cloudy rainy week. The only power storage that makes a difference to me is pumped hydro like our Snowy 2.0. But it's constrained by its location, and it's taking a decade to build.

I'm not sure what's the way forward. Maybe more wind farms can complement solar, but I guess that probably means we should really be deploying more wind farms rather than solar at this point.

[cbmuser]

» Every time I saw this kind of discussions, my first question is, what happens when sun is not shining? Like in the night or when it's very cloudy?«

We're burning coal or gas. At least that's what happening in Germany which had to reactive 19 coal-fired power plants with a total capacity of 7.3 GW after shutting down 8.4 GW of nuclear capacity.

See: https://www.smard.de/home/rueckkehr-von-kohlekraftwerken-an-...

Don't be like Germany, support nuclear!

[thecopy]

Dont let perfect be the enemy of good.

This HN thread might interest you [1] "A near 100% renewables grid is well within reach, and with little storage"

From one of the comments:

>That's what is different about this new study. It uses real time supply/demand figures instead of annualized averages. It meets 98.8% of demand with renewables and fills in with fossil power the rest of the time.

1 https://news.ycombinator.com/item?id=32580844

[upsuper]

I was not saying we have to be all on renewable perfectly. We are too far from even reaching a reasonable level. Power generation at night is dominated by coal plants.

The linked article is interesting, and it kinda confirms what I was wondering that it is probably wind farms that we need way more, not solar.

[karmakaze]

The top comment there:

> "in Australia" is an important qualification here. Australia has a very high ratio of available solar and wind energy to population.

"Don't let perfect be the enemy of good." doesn't mean not to think it through. Show me the math.

[TheLoafOfBread]

Whole renewable energy industry is dead end without usable grid scale storage.

Like inventing a car without brakes.

[defrost]

Things take time.

Currently there's more than 100 concentrated solar thermal plants, generating 7GWh of power, deployed around the world with a another 30 under construction right now in China and a third generation plant being designed here in Australia while the second gen is currently being built and tested after the success of first gen pilot.

https://theconversation.com/batteries-wont-cut-it-we-need-so...

It's happening, it just hasn't yet arrived at scale.

In parallel we're also seeing the rise of solar -> green hydrogen | ammonia | methanol for use in heavy primary industry (mining and transport) which is a decent chunk of fossil fuel use to be displaced.

[cbmuser]

»It's happening, it just hasn't yet arrived at scale.«

Making it at scale is a MAJOR challenge.

Germany alone consumes up to 1.6 billion kWh on a single day. That's the capacity of 16 million Tesla-S batteries with 100 kWh.

Solving the storage problem is simply infeasible and is never going to happen in the foreseeable future!

[plastic3169]

Germany has 50 million cars. Are you saying that after those have been turned eletric their batteries alone would be enough to cover the countrys battery needs?

[TheLoafOfBread]

Usually people buy cars to drive them around, not to use them as batteries for poorly designed grids.

[defrost]

Ergo the rise of concentrated solar thermal plants (CSPS) and using excess peak solar to produce hydrogen, ammonia, methonal, etc for off peak (night time) demand.

Batteries aren't the only way in which energy can be offset by 10 hours to meet lower night time demand.

[Kon5ole]

Renewables still help without storage. Every TWh of electricity produced from wind and solar is a TWh that was not produced by burning coal. If you reduce the coal consumption in the existing coal power plants by 50% it's as beneficial as closing half the number of plants.

That said sure, we need to build storage, and I think the first and most important step is to remove the political obstacles currently in place to prevent people and companies from generating and storing their own electricity.

[cinntaile]

Assuming there is no solution to when the sun is not shining you still managed to reduce the usage of coal, no?

[TheLoafOfBread]

No, because you can't switch off the coal power plant on spot, it takes around a week.

[cinntaile]

You can (and this is being done in practice) regulate the power output instead of turning it off completely and then turning it on again, doing it your way would be extremely detrimental to the power plant's life due to thermal stress. It's also the case that different coal plants have different capabilities so when you claim it takes a around week to turn off a plant, you should provide some more information about the plant (type) you're talking about.

[TheLoafOfBread]

You can disconnect output, yet you need to still burn coal anyway, unless you want to damage the coal power plant.

[cinntaile]

I'm not talking about disconnecting output, I'm talking about reducing it. You don't burn as much coal, which was my original statement.

[cbmuser]

You actually can and we're doing that in Germany. The plants remain on stand-by.

However, you always need conventional power plants on the grid as otherwise you won't be able to do load-following.

Most 100%-renewable-energy plans suffer from a deficit of knowledge how large electricity grids actually work.

There is a reason why there is no 100%-renewable-energy grid anywhere in the world which does not heavily rely on hydro power or geothermal power.

[TheLoafOfBread]

But you are still burning coal, because you need to keep them hot, otherwise they will get damaged.

[hef19898]

400+ GW of installed solar in 2023 seems hardly a dead end...

[TheLoafOfBread]

That's installed. How much energy does it produce during night? 0W

[hef19898]

Assuming a balanced installation across the world, that number is more like 200 GW. But whatever.

[sokoloff]

The energy produced in a day from a solar panel is closer to 4-5 hours of its peak rating, not 12 as your statement suggests.

[cbmuser]

Yes, because electricity consumers in the US profit at night when solar cells in Asia are generating electricity. /s

[hef19898]

That wasn't the question so, was it?

[brucethemoose2]

I have been told that the big problem is actually transmission and load scaling.

Energy storage is a big part of that, but really boring, non headline grabbing things like better/more transmission lines and slightly more sane usage patterns make up the low hanging fruit.

[TheLoafOfBread]

Solar/wind power plant + storage at the same place and consider it as one unit. Then you have a powerplant which can supply electricity on demand (as gas, coal, nuclear can) and you don't need to worry about rebuilding whole grid.

[brucethemoose2]

But ultimately you still need to move the electricity.

I know in Texas, we are largely making more wind/solar power than we can even transmit. There are projects to address this, but they are slow.

[cbmuser]

You still have the unresolved problem that wind and solar do not produce on-demand.

Any other market would have dropped a production machine already that does not produce on-demand.

It's like having a worker that only works when they feel working and be it 3 AM in the morning. No company boss would accept such a behavior in the long term.

For wind and solar, it's just widely accepted and rather than accepting that you can't build an electricity grid on top of unreliable generation, people try to come up with all kind of weird solutions to force a solution based on solar and wind.

[hef19898]

And seem to fail to understand that industrial electricity demand is flexible nowadays. And has been for almost a decade now.

So to put it in your words, yes, companies are absolutely accepting that kind of behaviour from their electricity suppliers. Companies are even benefiting greatly from it.

[izacus]

> Every time I saw this kind of discussions, my first question is, what happens when sun is not shining? Like in the night or when it's very cloudy?

What's been happening now in Europe - the electricity prices go negative during the day and in the evenings the gas plants are turned on and start burning fossil fuels again to make up for the demand.

Luckily in some places it's supplanted by wind (when available - e.g. Germany), but a lot of EU countries just burn gas in those examples.

[Kon5ole]

The basic idea is to produce enough power when the sun shines to last when it doesn't shine, by using some kind of energy storage. Batteries are one option.

How long batteries last is controlled entirely by how long you want them to last. A 2 hour installation is made to last 2 hours, if you attach it to half as many consumers it will last 4 hours, if you double the size as well it will last 8 hours. Some modern EV's can power a single home for several days.

Another interesting option is to synthesize gas. Australia could for example power Sydney from solar+batteries+synthesized gas by the end of this decade if they wanted to, construction could start tomorrow.

It seems that worldwide, the main obstacle really is "Wanting to". Everybody says they want to but there are so many economic structures closely tied to the status quo that actual change is quite slow.

[data_maan]

Just imagine what would happen if lawmakers decided that it would be illegal for end consumers to use fossil fuels in the night if you have fossil fuels during the day... :D:D

After an initial "WTF I have to go to sleep now, because there's no electricity?!", people would get crazy innovative and find new solutions, and -to some extent- adapt.

Unfortunately law makers are not keen on making people suffer a little now, in order to avoid a whole more of suffering later, once climate change effects hit irreversibly and tangibly.

[cbmuser]

»After an initial "WTF I have to go to sleep now, because there's no electricity?!", people would get crazy innovative and find new solutions, and -to some extent- adapt.«

You cannot enforce innovations. That's not how it works, really!

[mstipetic]

Well read up on it then instead of constantly asking basic questions. Do you think nobody ever thought of that?