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Comment by cbmuser | Hacker News Reader

Renewables _always_ require a fossile backup. You are _not_ fixing the climate with just renewables.

Look at electricitymap.org and compare the emissions of Germany (50% renewables) with France (70% nuclear). Germany is 7 times dirtier in its electricity sector.

I don’t understand why people keep repeating that non-sense that renewables reduce emissions at large scale, they don’t.

And building NPPs fast is no problem, look at China and Russia. Heck, Japan used to build new plants in just about three years.

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That's simply untrue. Iceland for example is already 100% renewable. Other grids with large installed hydro generation (eg New Zealand) could move to solely renewable with the installation of more intermittent generation and transmission infrastructure.

Yes, most grids still rely on non renewable resources. But that is simply a relic of the fact that they were built that way. The existing examples prove it's possible.

That’s the equivalent of saying “be born rich” to a poor person. Iceland is running on geothermal which most places don’t have and dams are a non-starter in the vast majority of river systems due to the ecological destruction.

There are no countries running on wind/solar, which is the only renewable technology that can actually run everywhere.

Iceland also has the population of a small to midsized city (~300k, if I recall correctly).

The comment I was replying to stated that "Renewables _always_ require a fossil backup". This is clearly untrue, as the multiple examples of grids that do not have or need fossil backup shows.

Certainly the examples I have given are those that have the easiest path to renewables. It is entirely logical that they would be the first to transition. But it proves that it's possible.

Hydroelectric power isn't quite as clean as many believe though.

>We estimate that GHG emissions from reservoir water surfaces account for 0.8 (0.5–1.2) Pg CO2 equivalents per year, with the majority of this forcing due to CH4.

https://academic.oup.com/bioscience/article/66/11/949/275427...

That's between 2% and 3% of our global greenhouse gas emissions. About three quarters of greenhouse gas emissions come from energy production and about 15% of all energy production is hydro power if I recall correctly.

It's much better than fossil fuels, but not quite clean.

> Renewables _always_ require a fossil backup.

If the backup is run infrequently enough then that becomes a non-issue. I can definitely forsee a future where the fossil backup is only used once a decade in particularly abnormal weather conditions.

It would be possible if you have a huge well-connected grid, spanning thousands of kilometers, with low costs of sending energy over long distances and small energy loss (ideally, spanning multiple timezones, or connecting sunny regions and windy regions with the less renewable-friendly ones).

There has been some research into this topic, but we're not there yet. First, the connectedness of e.g. EU grid is not that high. Second, it's a very political subject in a way (everyone wants to be energy independent on its own, without needing to import too much). Finally, IMO Europe is not that big to be sustainable on its own regardless of weather (which is often similar on large part of continent).

Alternatively we build out masses of storage capacity, coupled with much more aggressive load shifting (this would be disruptive to the economy, but not overwhelmingly so). We're not there yet either, but it doesn't seem like an insurmountable problem to me.

I agree with you that it probably can be done. The question is whether it can be done without using more energy than it saves.

Ah yes, let’s use the last country to see a massive nuclear disaster as a model. That will end well! /s

We’d need less “dirty” backups if we invested more in batteries.

Every power source requires some reserve capacity; nuclear goes offline for long periods of time to refuel, for example. Large generators trip offline.

Germany emissions don't come from the 50% renewables, they come from burning 50% coal. I'm not sure why you are blaming renewables for those coal emissions.

France is currently at 23% renewables:

https://www.electricitymap.org/zone/FR

Will you blame their current emissions on renewables? No because if you click on the "emissions" tab you'll see that it's almost all coming from gas, and second highest source of emissions are nuclear.

Does nuclear always require a fossil fuel backup? No, of course not, so there's no need to make up false rules about other sources. Wind reserves can come from hydro, geographically distant wind (offshore is running at insanely high capacity factors these day), batteries as we start to deploy them, and yes even from existing nuclear plants.

But having built nuclear many years ago, and Russia and China building some now, doesn't mean that France or Germany or the US will be successful when they try to build. However, the one thing they have been successful at is building more wind. I hope they lean into their strengths, instead of betting everything on something they have repeatedly failed at.

Please look at the latest Germany figures: https://energy-charts.info/charts/energy_pie/chart.htm?l=en&...

Germany coal percentage in electricity production in 2020 is 21% and 66% of electricity generation is 0 carbon (renewable + nuclear). Coal part in total production is decreasing year over year.

Of course Germany is using other country to import when wind is not blowing, but at the scale of a continent we can see that most west European countries can go soon to an almost 0% carbon electricity production.

Yes, I've looked at those, but I don't see what your point is. The carbon comes from coal, not renewables. When you see a mix of 50% coal and 50% renewables, and you blame Germany for high emissions by not even mentioning the coal, I kind of wonder what's going on in the poster's head. I have seen this repeated again and again in this thread, and I literally can not comprehend the logic that chains these types of statements together, because the only connections seem to be huge and incorrect logical leaps, so I therefore have not engaged with what seems to have no logical way forward for discussion.

I will say this: Europe has been decreasing its carbon emissions by replacing fossil fuels with renewables. Renewables reduce carbon emissions everywhere that they replace fossil fuels. This is just physics.

My point (I'm not the OP) was that Germany situation is even better than what you stated :) and that as of today the 50% coal is in reality 20%.

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