[Retric]

> over much longer time periods

It’s not clear there would be much longer time periods. Build enough low carbon generation to guarantee a surplus every day and you have a surplus every day.

Anyone claiming we need days worth of storage is inherently making an argument that days worth of storage is cheaper than simply building more generation and generation is really cheap while batteries aren’t.

[pfdietz]

We can get hard numbers on the storage required using this simulation/optimization site:

https://model.energy/

I often point to this, but it's such a fun and useful site I'll do it again.

What you get is typically (it depends on where you are) producing steady output from solar + wind requires some hours of batteries (typically much less than a day) and usually a fairly large backup of hydrogen (particularly far from the equator). The hydrogen gets burned in combined cycle plants with a mediocre round trip efficiency; most of the stored energy goes through batteries and back again at high round trip efficiency.

So, yes, one does need days worth of storage, but it's not batteries, it's a rainy day hydrogen account where storage capacity is very cheap.

[nox101]

According to several studies you need up to 2 weeks of storage, not just 24hrs, because checking on the long term, every decade or 2 you get 2 weeks of clouds or 2 weeks of no wind, etc....

[Retric]

> 2 weeks of clouds or 2 weeks of no wind

AND not OR. To actually need 2 weeks of storage you would need both 0 output in solar for 2 weeks and 0 wind for two weeks and 0 output from hydro. That doesn’t happen.

You still get solar power on cloudy days, it just takes more panels to generate some specific level of power.

The goal is to minimize X$ for generation + Y$ for storage while guaranteeing sufficient supply. Any study approaching things from any other set of assumptions is going to give you nonsensical answers.

[tonyarkles]

So I'm living up north here where from Nov 15 to Jan 26 we get less than 9 hours of daylight per day and the sun is at a low angle above the horizon. We won't be generating anywhere near nameplate capacity even if the sky is clear due to the ubiquity. Add clouds and the short day... and it's really rough for a few months. Sometimes it's windy when it's dark and cold, and sometimes it just stays cloudy and calm for a while. To make it through the winter here you're going to need to either build out massive amounts of storage or dramatically over-provision the wind and solar and deal with curtailing it in the summer.

[kelnos]

This is why advances in even-longer transmission lines will be necessary. Even if you your power is generated 3000km south of you and needs to be shipped up, the transmission line losses will only be, what, around 10% or so? That might mean your electricity is a little more expensive than it is for people who live farther south, but it's probably still cheaper than what we have now.

[7thaccount]

The idea of an HVDC macrogrid is possible, but will be hard to believe expensive and would be a huge vulnerability.

[Retric]

Sending a meaningful chunk of US electricity through HVDC lines is probably not that expensive.

A hypothetical estimate of 100% NYC’s electricity from Southern Arizona to NYC across HVDC adds up to ~1,300$/per person for infrastructure that lasts ~50 years.

East/west is even cheaper because people on both ends would want to move electricity. Florida solar kicks in early in the morning for California and California solar is still available late into the evening Florida time. You have some losses across HVDC, but you have losses and battery degradation with storage.

[rgmerk]

Corollary: energy is going to much more expensive the further you get away from the equator (in the absence of very predictable winds/lots of hydro/cheap geothermal).

[tonyarkles]

Yup… we’re probably building nuke plants. We are also building wind and solar. And some new natural gas plants. We don’t really have a whole lot left to tap for hydro, don’t really have good geography for pumped hydro storage, and while there is a pilot project on the go to try to generate electricity from mediocre geothermal we definitely don’t have good geothermal potential either. But… we sure grow a lot of food! And are starting to look at shuttering the coal plants.

[pfdietz]

No, we'll build lots of wind, and also smooth long term imbalances with hydrogen.

Heavy industry will tend to migrate to sunnier areas.

[hnaccount_rng]

That is the opposite of what we are seeing though. Which largely comes down to "hydro works really well with melting snow" and some level of "it's windy up here". But for solar, you probably have a point

[medoc]

> You still get solar power on cloudy days, it just takes more panels to generate some specific level of power. That is wrong. On cloudy winter days the inverters often just stop. Source: have 20kW of panels on a house in the south of France.

[Retric]

That’s a technical problem on your end. I still get electricity on cloudy days when the panels are covered in inches of snow.

Now my personal power output does tank during this period, but such extremes are local events. Further hydro, nuclear, and geothermal just don’t care about clouds.

[beAbU]

Theres something wrong with your setup. I get about 10-15w of production in the dead of night with a full moon. Source: 5.5kW of panels on a house in South Africa.

[jillesvangurp]

There are counter arguments to this. Clouds and wind are local weather patterns. We can use cables to move power around between areas with and without clouds. Moving power over large distances has gotten more feasible with high voltage direct current (HVDC) cables. There are a few projects in the works to move power from e.g. Australia to Singapore and Morocco to the UK. And there are already cables moving power between e.g. Canada and California, Norway and various countries in Europe, etc. More cables means more resilience in the grid. Continent wide absence of wind and solar generation is not a thing that happens a lot. Certainly not for weeks.

Another point here is that demand shaping is an effective way to deal with fluctuating supply of power. By creating financial incentives, you can get energy consumers to scale up or down their consumption of power. Night tariffs are still common in places with a lot of static generation, for example. With solar generation now being so common, we even get occasional negative energy rates in some places where the static generation can't be scaled down.

Batteries and cables are a key enabler for demand shaping. Also, the time windows that energy gets sold for are getting shorter. It used to be that you'd buy x amounts of mwh for some price for hours. It's now getting down to minutes. That means grids can respond more rapidly to fluctuations in supply and demand. And of course it creates incentives for companies to invest in being able to scale up or down their energy consumption from the grid and benefit from these price fluctuations. For example by having batteries and using their roofs for solar generation.

Base load is of course a very flimsy concept and the discussions about it tend to be very hand wavy and rarely cite specific numbers in GW needed. Because as soon as you do that, you can talk solutions: cables, storage, more solar (it always generates some power), etc. And cost.

Hysterical assertions that we need to spend double digit percentages of GDP on things like nuclear or fusion kind of fall over when you apply some rationality to that. How much power for how much $? Maybe do something less mad and cheaper instead. Build some cables. Add some off shore wind. Much cheaper, faster, and way less risky.

Of course the reality is that we still have plenty of base load for the foreseeable future. That's why the vast increases in wind and solar generation, which are now the dominant source of power in a growing number of places, isn't really causing any outages or rolling blackouts. Whatever amount of base load we need, apparently it's way less than we currently have because we have been removing lots of it from the grid.

[TheOtherHobbes]

A reminder that 40% of the world's shipping is just there to move oil and gas around.

If someone was starting from scratch and looking at fossils, the arguments against would be so obvious and compelling that any arguments for would look insane. Nukes aren't much better.

The arguments against renewables are purely opportunistic and political.

We need clean energy now, not 10/20/50 years from now. We could have clean energy with some fairly cheap local build out - panels over carparks, for example - combined with regional power farms, and buffered with existing storage technologies and an improved grid.

https://www.forbes.com/sites/nishandegnarain/2020/09/25/loud...

[nradov]

Sounds good, but even in the most optimistic scenario it will take decades to build out significant storage capacity and the supporting grid improvements. None of that will be cheap. Expect electricity prices to continue rising even as the cost of solar generation falls.

[Retric]

It may be decades to hit 100%, but the grid can be 90% carbon free reasonably quickly at which point there’s far less need to hurry.

Further, the economics will dictate what happens not just our current predictions. It makes a real difference if solar panels are 25% or 30% efficient in 2035+ similarly how flexible demand for charging EV’s is and how expensive battery storage ends up being etc.

[Nasrudith]

Given the sheer thermodynamic effect of the earth's rotation I have to ask what would it even take to get 2 weeks without wind? It would probably take at least globe spanning superconductors or very careful heating of the world to ensure constant temperatures in order to not have wind from the temperature cycling. That is 'Dyson sphere builders fooling around with their power for laughs' territory.