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goodsam2 t1_j7vmfl4 wrote

Reply to comment by ForHidingSquirrels in Renewables are on track to satiate the world's appetite for electricity by ForHidingSquirrels

I just don't see how it's possible with current tech.

I'm a huge optimist with renewables with batteries and their S curves. I just think we have all the answers to increase renewables and batteries for another decade(which we probably have a better idea of what to do in a decade in 8/9 years) but having a 100% wind/solar grid with batteries is hella expensive, some firm dispatchable energy is required. The amount of solar panels equal to 100% up time goes up a stupid amount.

I think we get to a floor of 60% renewable(based on current tech) but 100% is a problem.

Hydro can fill this some places but others I'm not so sure.

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dontpet t1_j7vtzhd wrote

I look forward to the time when we are confronting the question of what to do about the last 10%.

I suspect we will have much better answers by then than nuclear power.

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goodsam2 t1_j7vx1ov wrote

Me too.

Yeah I mean some niche places are getting close to the upper end but renewables can get us rather far.

Yeah we have clear answers about what to add on the marginal short to medium term for decarbonization. Something like 60% renewable on average is the estimated floor I've seen and by the time we get closer to that we'll know what to do for the next part or at least yeah a better idea.

I think geothermal is a clear winner with improved drilling techniques. Leading to less obvious geothermal being added. IDK how far that goes but lots of places could add some.

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stevey_frac t1_j7ysvcs wrote

They are demonstrating geothermal boreholes with plasma drills now. The plan is to do a 20km deep borehole, in just 100 days, next year.

If that is actually achievable, we can drill a borehole next to every single coal plant in the world, and run the turbine off of super critical geothermal steam... Basically forever.

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stevey_frac t1_j7ysn4t wrote

Because you don't just use all solar?

You mix solar, with geo-seperated wind farms, and existing hydro resources.

It tends to be sunny during the day and windy at night. It tends to be sunny in the summer and windy in winter. They kind of naturally dovetail. Also, off -Shore wind has incredibly high capacity factors...

Batteries, especially cheap and durable LFP batteries can definitely help cover peak loads, and then we start talking long scale storage, with things like ammonia / hydrogen storage, where we can start storing weeks worth of energy.

And even still, you probably have natural gas turbines hanging around for a few decades for those low periods, but we use them less and less as we increase storage and over build our wind and solar installs.

Huge thermal storage for industrial process heat is also coming.

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goodsam2 t1_j7z6raw wrote

>And even still, you probably have natural gas turbines hanging around for a few decades for those low periods, but we use them less and less as we increase storage and over build our wind and solar installs.

That's not the 100% promised that I don't think we have answers to. We have answers for the next step for a decade+ but don't know the grid at 100% carbon free.

With geothermal like you mentioned in your other comment the math all works fine on top of already built hydro.

The study I always talks about 80% renewables with 12 hours of batteries (which is a shit ton) and 20% firm hydro, nuclear geothermal, biomass etc.

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stevey_frac t1_j830yme wrote

I mean, the batteries are already coming. Ontario is bringing a 250 MW battery facility online point the next two years, as a part of a plan to deploy 1500 MW worth of battery capacity.

That's nearly 10% of our average demand being supplied by batteries, and it's cost effective to do so...

We can charge them with cheap overnight power, and use it to trim our peaks... Or prevent wind turbine from curtailing by starting to charge our battery banks.

12h hours of battery storage for our province should come out to only about 20 billion assuming you can do it with $100/kwh with LFP cells.

Considering we just spent $13 billion on a nuclear refurbishment, this doesn't seem crazy levels of investment at all.

My number might be a bit optimistic, but I'm assuming building the biggest battery plant in the world will net you some discounts.

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rileyoneill t1_j7xx08e wrote

Here in California there are periods where during the day, renewables cover 70% of the demand on the CAISO. 15 years ago critics were claiming it was never going to surpass 10%. If we double the current solar, on most days, when the sun is shining, the solar output would be comparable to the total demand.

Renewables are dropping so much in price that it will be soon cheaper for households in the US to full rooftop solar and battery storage and then only buy the absolute minimum energy from the grid.

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goodsam2 t1_j7xxl3x wrote

But that's the thing is that California has a bunch of natural gas peaked plants because it's hard to get over 70% renewable.

I mean double the solar panels and you are adding excess capacity at the wrong times. The duck curve is a thing so the marginal value added from a solar panel means getting over 80% is incredibly hard with batteries.

Having some amount of firm and dispatchable power is necessary unless our batteries improve an insane amount. Lithium ion isn't the best store of electricity over say 6 months when you are banking solar energy from the winter.

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rileyoneill t1_j7y3g6n wrote

We had all the natural gas first. The renewables have only really been added over the last 10 years, and the majority of them since like 2016. That 70% is not any sort of hard limit. It was literally the maximum renewable today on the CAISO. Despite still being winter, our solar still puts out and hits its capacity all the time. We get sunshine in the winter months.

We do not have more solar than we have demand. Solar is around 13GW on the CAISO. The demand has never been under 18GW, most days its in the mid 20s, and in the summer days its in the 30-50GW range. So this idea that solar over producing is somehow a big problem is not founded on reality.

We do not need batteries for 6 months. We only need batteries for about 2 days, and even 8 hours would reduce our natural gas consumption considerably.

The plan is to keep installing solar, wind, and batteries and gradually ween off natural gas, to eventually between those three main systems we are not running natural gas. We might keep the plants around and they might get fired up 2 weeks a year, but it would be an enormous reduction.

We have about 10GWH of battery on the CAISO. I figure we are about 1% where it needs to be.

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goodsam2 t1_j7y3zot wrote

https://www.bloomberg.com/news/articles/2021-08-19/california-to-build-temporary-gas-plants-to-avoid-blackouts

The point is not maximum 100% is easy but 100% on the cloudy not windy days you need electricity. There is 0 downtime.

There is enough to continue to reduce consumption but there basically is not a 100% renewable grid. The natural gas would be run sporadically contributing around 10% of power on the low end.

Getting to 100% electricity is hard with renewables. I'm not disputing 60% or even up to like 80%, 90% is a little niche these days.

We have the technology to make massive improvements but not the answer to 100% renewable 0 down time.

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dunderpust t1_j7yo1i9 wrote

Some people thinks that this means we can just give up on renewables. As if in 20 years time, when we are reaching the crunch points, we will had have no technological development at all. Heck, if massive electrification happens and we get, say, 70% of our energy needs from low-carbon sources, we have already bought ourselves time for further technological development, and that's a huge boon already.

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goodsam2 t1_j7z6xd1 wrote

Yeah but it's a huge distinction. We don't have the technology to finish the job but we do have the technology for the next steps for a decade+

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dunderpust t1_j828fx6 wrote

Yep, no excuse for not going full speed ahead.

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rileyoneill t1_j830cq4 wrote

We have enough natural gas to run the entire grid during a windless and cloudy day. Our demand on those days is usually fairly low. The extra deman for brownouts was due to us having brief periods of 50GW of demand during an extreme heatwave.

The periods of extreme demand do not occur during cloudless days, the demand is brought on by AC. I have never seen on the CAISO where the daytime solar demand is under 20%, statewide storms like that are extremely rare.

My point is that if we are 90% renewables and 10% natural gas, that is a huge improvement. Then perhaps it can be 91% and 9% natural gas.

Because 6 months out of the year is extremely predictable weather regarding sunshine, we can probably get by with 300GWH of battery, 70GW of solar, and 25GW of wind. May 1st, October 31st could likely be 95% renewable.

Tony Seba of Rethink X made a presentation where they actually went and tracked historical weather data, then designed a system that would have 100% uptime. They then took the cost projected prices for renewables and gave capacity numbers for solar, wind and battery storage for California, Texas, and New England.

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https://www.youtube.com/watch?v=6zgwiQ6BoLA

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The main idea is that solar will be so cheap that it will be viable to just overbuild by some huge factor so that on cloudy days where output is diminished by 80%, the remaining 20% is still collecting and that 20% is enough to satisfy demand, taking the edge off the batteries.

In one example he proposed 330GW of solar for California. Our normal demand is 20-35GW (with peak summer at 50GW). But it would be 30GW powering the grid and 300GW charging batteries. So every 1 hour of sunshine covers 8-10 hours of battery storage.

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