What is the real limit of expanding solar+wind power?

I don't understand this at all.

I can see a grid alternate between 22% -> 55% renewable energy one day, then 26% -> 48% the next day and ponder what that will look like when even more wind and solar get added.
Negative prices, exploding prices, the demand and supply of electricity have to match at all times.
in the op, you wrote

I thought that solar + wind power can't go above 20% of an interconnected power grid without disaster.

to prove this, you listed

Let's see where we were in 2020 since that is good data.

Europe-27 - Solar+Wind 19%
(All the countries connect together into effectively one power grid with various levels of connectivity)
EU Power Sector 2020 | Electricity Trends | Ember (ember-climate.org)

USA - Solar+Wind 11.6%
(All the lower 48 states, except Texas, connect together into an eastern and western power grid)
(*I can't figure out how to pull Texas out of that 11.6%. The real number should be a bit lower than 11.6% for the lower 48 states)
Renewables = 20.6% of US Electricity in 2020 - CleanTechnica

Texas - Solar+Wind 25%
Graphic Shows What Percentage of Texas' Energy Is Renewable (newsweek.com)

Australia - Solar+Wind 18%
Electricity generation | energy.gov.au

which is just the current state of the grid, it does not display what capacity is possible, but what capacity countries have decided to go for

i refer back to my punching comparison

or i could rephrase the punch: i think that me, angst, cannot post more than 14,538 posts without dying. seeing that i've posted 14,538, and i'm not dead, this proves that if i post another post, i will be dead, and that this is the possible # of posts i can make

see the problem?

(and as is probable, my current post count will probably change after i posted this, as the grid also does; change. point is that simply listing the current percentage of power sources doesn't do anything much but list the current percentage of power sources)
 
The reality of the sun setting on a windless day means there needs to be enough fossil fuel, nuclear, or hydro to power the whole country at night.

No matter how much solar and wind expands, that remains true.

Perhaps my 20% overall figure is wrong.
 
Why wouldn't the solar farm provide higher net income to the farmer if they're replacing crop land with it?
 
The reality of the sun setting on a windless day means there needs to be enough fossil fuel, nuclear, or hydro to power the whole country at night.

No matter how much solar and wind expands, that remains true.

Perhaps my 20% overall figure is wrong.
the 20% cap may be true (it's not from the literature i've personally read, but i'm not here to discuss that); the point is just that the numbers are what's being done, which has no inherent connection as to what is possible

in the op, you just listed what was being done, not what was possible. the eu keeps expanding its fossil dependent grid every year, there's grants to fossil fuel companies - yes, while also expanding green energy, but the whole point is that the percentages are definitely a result of policy, and not inherently what the industry is capable of. the former may follow from the latter, but it's simply not surefire
 
Is there strongarming going on, taking the land from people who'd rather farm? But yeah, I can't imagine that it would allow the soil to regenerate underneath. Like, the shady thing in my yard has clover under it so I can get a twofer. But I'm not constantly tromping under it to kill the soil.
 
It's all just incentives. Solar farms prairies aren't. I assume there are lower density ways of doing it, they just aren't what's going up.
 
Thanks to wind power in Spain we have been experiencing abundant electricity excedents and negative prices lately ('we' here means wholesalers and such as us final consumers always have to pay handsomely thanks to our imaginative legislation). So wind power works apparently pretty well at the only cost of ruining many beautiful landscapes. There is a project to build the largest sea wind farm in the world in front of Cape Trafalgar (can hardly imagine a more windy place) which has met harsh opposition from tourist and fishing sectors (and the British who says it is a war grave :rolleyes: )

Solar power is also experimenting a huge boom at a more individual level to the point there are zones where it is difficult to look anywhere and not see a roof with some solar panels on it (I am going to install a good bunch of panels on my own too btw). However solar's more surface intensive nature is bringing up a new problem as many farmers find covering their lands with solar panels far more profitable than growing edible things, so some regions are making mandatory to plant a number of trees or similar vegetable stuff for every solar panel installed or something.
 
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British who says it is a war grave
That is one of the silliest reasons against wind farms I have heard, and there are some silly ones. From here:

Some 449 British and 4'408 French and Spanish seamen died during the battle​
Why then are the British the ones complaining?

which raged over a 20-30 mile stretch of the Spanish coast between Cadiz and Gibraltar.​

Does a battle stop land use for hundreds of years after?
 
That is one of the silliest reasons against wind farms I have heard, and there are some silly ones. From here:

Some 449 British and 4'408 French and Spanish seamen died during the battle​
Why then are the British the ones complaining?

which raged over a 20-30 mile stretch of the Spanish coast between Cadiz and Gibraltar.​

Does a battle stop land use for hundreds of years after?
I think it is not because the dead but because it is the scenery of the greatest British victory. In any case it is purely anecdotal as it won't determine anything. OTOH I can understand the touristic reason, it is one of the most scenic stretches of coastline in Spain, wouldn't like to see the sunset there ruined by thousand windmills. The fishing reason I am not very sure about. Don't know how it would affect sea life, I know such structures are beneficial in the long run since they are used as refuge by sea creatures.
 
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This research is funded, in part, by Eni S.p.A. through the MIT Energy Initiative, the U.S. National Science Foundation, and the Natural Sciences and Engineering Research Council of Canada.

"Eni S.p.A. is an Italian multinational energy company headquartered in Rome. Considered one of the seven "supermajor" oil companies in the world, it has operations in 69 countries with a market capitalization of US$54.08 billion, as of 11 April 2022." Wikipedia
 
The reality of the sun setting on a windless day means there needs to be enough fossil fuel, nuclear, or hydro to power the whole country at night.

No matter how much solar and wind expands, that remains true.

Perhaps my 20% overall figure is wrong.
You connect together a continent, and the wind is blowing, and the sun is shining. The solution is a large area smart grid.
 
And again, this is something that can be, and is, modelled for pretty easily from real world weather patterns. Like you can map weather records over a given spread and volume of VRE capacity and it's generally possible to produce nearly all required power, at nearly all times, from the sum and average of variable generation spread across a continent, along with surprisingly little (but still significant) storage. I promise everyone that modellers, engineers and planners have actually figured out that night time exists.

I posted this ANU model here earlier of a hypothetical 100% renewable grid at the cheapest costs (comparable to current grid) by overlaying Australian weather records on a model of installed capacity. They came up with storage having to meet 16 of about 200 TWh consumption per year, while everything else is met by wind (136), solar (36) and existing hydro (17). So the fullback position from that would be less storage and just filling that last little bit with some fossil fuel (presumably open cycle gas) and just having a 90% renewable grid for a while instead of 100%.

(Note that the ANU model is a few years old and solar is cheaper now, so would be a bigger part of the mix than shown)

But the point is, it shows that if a form of 100% renewable grid was already installed on these parameters, including with the storage, it would work. Crudely, people are arguing against increasing from 20% to 90% because that last step to 100% is maybe a bit hard.

80% or 90% does seem to probably be where a lot of countries are heading as the solar and wind installation really accelerates over the next fifteen years or so. Here's where the Australian grid operator sees things going, with Step Change considered the likeliest:

AEMOispfig16.jpg
 
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Current tech is mostly already out of date. see @Arwon above. I would suspect that in a decade solar and wind tech will be very different. I don't know if they will solve the problems, but they will likely move us much closer to a solution.
 
Solar farms out in the countryside are pretty dumb. They replace the solar catch of plants. Should probably move towards getting paneled surface on the top of almost everything we're already ruining, like the tops of buildings and corporate lawns around warehouses and stuff.
The best place for solar panel is parking lots. No plant hidden from sun as it's all built anyway, and it also shade cars and people reaching from them from heat and rain. And it cools down concrete, which helps immensely in local temperature.
(also as you said, top of buildings)
 
‘No miracles needed’: Prof Mark Jacobson on how wind, sun and water can power the world

The influential academic says renewables alone can halt climate crisis, with technologies such as carbon capture expensive wastes of time

“Combustion is the problem – when you’re continuing to burn something, that’s not solving the problem,” says Prof Mark Jacobson.

The Stanford University academic has a compelling pitch: the world can rapidly get 100% of its energy from renewable sources with, as the title of his new book says, “no miracles needed”.

Wind, water and solar can provide plentiful and cheap power, he argues, ending the carbon emissions driving the climate crisis, slashing deadly air pollution and ensuring energy security. Carbon capture and storage, biofuels, new nuclear and other technologies are expensive wastes of time, he argues.

“Bill Gates said we have to put a lot of money into miracle technologies,” Jacobson says. “But we don’t – we have the technologies that we need. We have wind, solar, geothermal, hydro, electric cars. We have batteries, heat pumps, energy efficiency. We have 95% of the technologies right now that we need to solve the problem.” The missing 5% is for long-distance aircraft and ships, he says, for which hydrogen-powered fuel cells can be developed.

Jacobson believes progress towards a 100% renewable energy system can be fast: “The goal is 80% by 2030, and 100% by 2050. But, ideally, if we can get 80% by 2030, we should get 100% by 2035 to 2040.”

Storage can be batteries, pumped hydro, flywheels, compressed air and lowering and raising heavy weights. Jacobson thinks batteries will win, but says others could contribute if they can compete on cost. New research indicates that electric vehicle batteries alone could provide the short-term storage needed by global grids as early as 2030.

Jacobson also advocates heat storage for some buildings: “Storing heat in boreholes, aquifers or water pits is dirt cheap, excuse the pun. It’s less than $1 a kilowatt hour of storage.”

New nuclear plants are too slow to build and too expensive compared with wind and solar, in Jacobson’s view: “You end up waiting 15 to 20 years longer, for a seven to eight times higher electricity price – it just makes no sense. Even if they improve [build times], say to 12 years, that’s still way too long. We have cheaper, faster, safer technologies. Why waste time?”

Biofuels are also dismissed by Jacobson: “The biofuels push was really not helpful. They hold constant, or increase, air pollution and they use a huge amount of land.”

He is a little more measured when it comes to direct air capture (DAC): technologies that can suck CO2 from the air for burial. It has no role today, he says, with spending on renewables far more cost effective in cutting emissions. But even when fossil fuel burning ends, many scientists have concluded that CO2 will have to be drawn from the air to avoid the worst effects of the climate crisis. At that point, Jacobson says, the costs of DAC should be compared with other ways to sequester carbon and limit global heating, such as reforestation and cutting emissions of other more powerful greenhouse gases, including methane from livestock and nitrous oxide from fertilisers.


Hybrid power park with solar panels and wind turbines in Sabugal, Portugal
 
I'm curious as to how he reconciles agriculture.
 
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