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Comment by dahfizz | Hacker News Reader

How do you power the grid with 90% solar when the sun only shines 40% of the day during the winter?

Renewable optimists consistently under-estimate the storage problem by orders of magnitude. We don't have enough batteries on Earth to hold one single day's worth of electricity. And for us to actually rely on solar, we would need to store multiple months of electricity to survive the winter.

Solar is cheap because you're comparing a generation source that works on occasion with a generation source that works 24/7.

I'm not anti-solar at all. But I am realistic about what we can and can't do with it. The thing that will make a solar grid practical _today_ is focusing on variable loads. When the sun is shining, we should be cranking the AC of every home and office, smelting aluminum, filling dams, etc.

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>How do you power the grid with 90% solar when the sun only shines 40% of the day during the winter?

Maybe not the national grid, but there are plenty of places in the US where the sun shines a lot more than 40% of the day during the winter. Start there. If Southern CA, AZ, NM, TX, FL, etc.. which all get a ton of sun no matter the season can reduce their reliance on the federal grid, that's a hell of a start, and we should be celebrating that as a great first step and building off of that.

I thought the whole point of alternative energy sources is acknowledging that certain locales have potential for different energy sources (solar, hydroelectric, wind, etc..) and we should as a society should take full advantage of that? We know oil isn't going away any time soon, but why aren't we saying "oh City XYZ or State ABC is abundant in (alternative energy source), let's make use of that as best as we can"?

> Maybe not the national grid, but there are plenty of places in the US where the sun shines a lot more than 40% of the day during the winter.

It looks like Los Angeles only averages about 37% for the year as a whole, and Albuquerque averages about 38%, so I'm skeptical that there's anywhere that gets "a lot more than 40%" in winter. You have to take clouds into account as well, remember. Cloudy days exist even in desert areas.

https://en.wikipedia.org/wiki/List_of_cities_by_sunshine_dur...

Thats 39% in ABQ of all hours in the year including night time.

Nobody is pretending that solar can provide electricity via night time generation. That's what storage systems and alternative sources are for.

The daylight story in ABQ is this:

> "It is sunny 78.9% of daylight hours. The remaining 21.1% of daylight hours are likely cloudy or with shade, haze or low sun intensity. "

http://www.albuquerque.climatemps.com/sunlight.php

Exactly - I've lived in AZ, FL, and spent a lot of time in SoCal. There is plenty of sun in those places.

If you can generate solar power 80% of daylight hours, that's a pretty good place to start.

Again, it's not an end-all-be-all solution. But you're talking about some very highly populated areas that could be using solar energy a hell of a lot more than they are now. Phoenix, Tucson, San Antonio, Dallas, LA, San Diego, Houston, Miami, Orlando, Las Vegas....that's a lot of places that could be utilizing solar power in a way that does move the needle. That's some 30-50 million people (if not slightly more) that could reduce their use of the federal grid in a measurable way.

I'm about 50 miles north of ABQ. I have a 6.7kW ground mount array. Using its rated output, and the average of 9.28 hours of sunshine per day, and no adjustment for hourly insolation variation I should get about 1.9MW a month. I actually get about 1MW, with not much variation from month to month.

I am optimistic that Santa Fe will soon see a new utility scale PV generation install that ought to generate power (with storage!) corresponding to roughly 1/3 of the city's residental use. The standard NIMBY-but-I'm-all-for-solar-have-some-myself crowd is out in force, however.

Some of these, maybe. It rains quite a lot in Miami and Houston -- Texas is big, and Houston is right on the Gulf Coast. It's more like New Orleans than it is Lubbock.

> Nobody is pretending that solar can provide electricity via night time generation.

The OP appeared to be suggesting exactly that.

It's like the (many) solar advocates who pretend that a solar nameplate capacity of x watts is equivalent to a conventional nameplate capacity of x watts, when in fact you're going to need 2x watts at a minimum, with an expensive storage system on top of that.

It's polite when reading something it's polite to interpret it in the way that makes the most sense.

Your last paragraph is something different -- that's not an implication that solar can generate at night. Note that levelized cost of energy does take into account that consideration (that why it's "levelized"). And renewables are trouncing new construction nuclear on that metric.

It sounds like a problem at first glance but it isn't. For one, there's an easy solution: overbuild solar. With solar generation that is 2x-3x peak demand, you only need 4 hour storage to have a robust, clean grid with near 0 downtime. Add a bit of longer term storage and you've got a grid that's more reliable than the one today.

That's the conceptually simple solution, but ofc there's more practical ones. Mix in wind, some nuclear, different storage solutions (Ev2grid, pumped hydro, rocks-in-a-box, etc..), demand-side solutions (VPPs), efficiency improvements (insulation, heatpumps), a few of the hundreds of advanced projects being researched (solar in space, enhanced geothermal, iron air batteries, SMRs, etc..). Combine the 1000s of solutions being proposed, researched and scaled out and you have a very solid plan of attack.

The comment didn't say "90% solar", it said "90% renewables". That includes hydro and wind, which don't stop at night or in the winter.

https://gridwatch.templar.co.uk/

Wind can be very low for days and low for weeks.

Hydro is ecologically devastating and there aren't enough sites for it.

Unlike oil and coal which are very ecologically beneficial?

That's not a fair reply at all. If we don't care about the ecology, then we might as well just continue to use petroleum!

Ecosystem damage from hydro is local, ecosystem from fossil fuel is global. We are heading for extinction as a species, and under such circumstances it makes sense to cause local ecosystem damage in the form of flooding.

> We are heading for extinction as a species, and under such circumstances [...]

We absolutely are not headed towards extinction as a species. We are like cockroaches and the human species will survive. Using "oh no, the human race is dying out altogether and we must preserve it all costs" is a ridiculous argument.

> [..] it makes sense to cause local ecosystem damage in the form of flooding.

It isn't just the (risk of) flooding. It's hubris to believe we can actually foresee all the second-order ramifications from such large-scale terraforming projects. (Hydroelectric) dams have devastated the local wildlife, transformed the surrounding permaculture for the worse, and set off horrible chain reactions with devastating consequences for the local flora and fauna which have global ramifications down the line, as we are discovering today. Nothing happens in a bubble.

This same argument was once made of fossil fuel emissions (when we thought that smog in the biggest industrial cities was our biggest problem and outsourcing them to developing nations was a great win-win /s). That obviously wasn't true. Why would you wish to repeat the same mistake?

We certainly aren't even close to going extinct.

I recommend reading actual IPCC projections and analysis rather than whatever media hype you've been fed.

Arguments aren't soldiers. It's both possible for hydro to be damaging and for it to be less damaging than coal.

There are really interesting innovations in hydro power ecology in the last many decades. Things like salmon runs, salmon ladders, and salmon cannons. (They benefit other freshwater fish, too, we just tend to like salmon the best in our naming scheme bias.) "Devastating" is a bit strong given all the work going into sustainable hydro power and environmentally aware hydro projects.

Current and near-future grid cannot handle such a balance of renewables, especially hydro takes a lot of beating when the water level goes up and down constantly.

Nobody is blind to the fact that the grid will need to be updated to be more flexible.

Thats a myth. You cannot have baseline power with renewables only throughout the year. Hydro only works in very specific places and the same for wind.

Yes, you may need various kinds of storage as well, filled by renewables. E-fuels can be used to shift energy across seasons.

Why? Build more. Interconnect with HVDC.

You don't you build solar and wind, which have different seasonal productions. Wind power is actually higher during winter. See: https://www.researchgate.net/figure/Estimated-normalized-mon...

And if you combine the graphs for solar and wind from this: https://aleasoft.com/european-solar-and-wind-energy-producti...

You can nicely see that they are complementary in terms of energy production.

You combine it with wind, batteries, and storage via an e-fuel like hydrogen.

The latter is crucial. The cost of providing "synthetic baseload" in Germany doubles if you don't include it.

See https://model.energy/ for optimization of an energy system using these to provide synthetic baseload, using various tweakable cost assumptions and historical weather data. The cost is not outrageous, likely well below new construction nuclear.

In a place like India, you don't even need wind and hydrogen. PV and batteries will do just fine.

There is an already pretty old (2013) study from Fraunhofer, which shows how 100% renewable energy in electric power and heating is possible in the medium term future (2050). Their ideas for storage are battery storage (52Gwh), pumped storage (60Gwh) and methane storage (86Twh) on the electric side.

See [1] for a very short English description and [2] for the German original.

[1] https://deepresource.wordpress.com/2017/09/16/blueprint-100-... [2] https://www.ise.fraunhofer.de/de/veroeffentlichungen/studien...

Exactly! We have led seasonal lives for thousands of years. This is no biggie.

Brownouts and blackouts lasting for weeks during windless winter weeks are hardly solution.

Trying to sell it as "no biggie" will not work well.

Having heat in the winter is, in fact, a biggie.

>How do you power the grid with 90% solar when the sun only shines 40% of the day during the winter?

Where?

Maybe we should try a more global approach to energy.

> Where?

Almost the entire world? The sun is up for less than 9.5 hours in winter unless you are very close to the equator.[1][2][3][4]

And that's assuming 0% cloud coverage. In reality, places like Germany only get an hour or two of real sunshine a day in the winter[5].

[1] https://www.timeanddate.com/sun/usa/new-york

[2] https://www.timeanddate.com/sun/usa/san-francisco

[3] https://www.timeanddate.com/sun/spain/madrid

[4] https://www.timeanddate.com/sun/china/beijing

[5] https://www.statista.com/statistics/982758/average-sunshine-...

The middle of winter in Europe, North America, and Asia is the middle of summer in South America, Southern Africa and Australia. Yes, global transmission of electricity is a problem. But the problem is not a global lack of sunshine.

Land - and thus population - is not evenly distributed across the globe, there is far more of both in the northern hemisphere.

Global transmission of electricity isn't a "problem," it's non-existant.

Transmission losses seem like a huge impediment to a global approach.

Long distance power transport is tricky for security reasons and also transmission losses (1% per 100 miles or so?).

Europe tried a very global approach to energy with Russia, went swimmingly for them.

Which is why it's so important to make Russia pay dearly. They didn't just attack Ukraine, they attacked civilization. Every human alive will suffer to at least a small extent as a result.

Russia must be confronted with economic, political, and yes, military incentives to behave very differently in the future, or at least to take more responsibility for the reckless actions of their leaders. In the meantime, working towards independence from fossil fuels has become even more important, even for those who aren't otherwise known for advocating good climate stewardship.

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