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Comment by ZeroGravitas | Hacker News Reader

> The only real solution is to make energy ubiquitous and plentiful.

Renewables have been the boring, consensus answer to this for about a decade.

There's some obscure academic discussions about the exact makeup of the last 15% of energy needs, but most of those options revolve around how to best reuse the massive amounts of nearly free electricity that a sensible overbuild of renewables will create at other times.

I know the mainstream media flips between it all being a hoax and us all going to die but I still don't understand how it's possible for so many HN posters to have a worldview that so neatly excludes these world shaking tech developments.

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The radical insistence on renewables as the ONLY energy source, and the equally radical opposition to Nuclear is part of why we aren't improving fission and researching fusion more, which would get us out of the woods.

No compromise is being pursued from the renewables side, while the nuclear side completely agree that renewables will be a major part of our grid.

The opposition to nuclear fission is no more radical than the "opposition" to Solar CSP, Tidal, Wave, Vertical Axis Wind, Hydrogen cars and heating etc.

We tried a few things and figured out what worked best. That sucks if you have a weird emotional attachment to one of those techs that didn't make the cut but that's life.

There's nothing radical in insisting on using a solution that you have now to a problem you have now. It's called being practical.

Nuclear is simply still too expensive to “overbuild” on, if we got costs down then sure, but we can’t just magic up all the capital needed to build and even maintain the plants, even if they are cheap to fuel. But right now solar, wind, and perhaps more hydro (if we aren’t at our limit yet) make more sense.

Wind, solar, and geo haven't really made up a significant enough portion of overall energy generation. Also they don't seem to be scaling up quickly enough. We're still seeing many coal plants operating and new ones coming online in the West.

> they don't seem to be scaling up quickly enough.

They're scaling up at a rate of 5% of total electricity production per year. And that rate is increasing by about 1/3 per year.

That's insanely quick.

https://electricenergyonline.com/article/energy/category/cli...

> IEA figures shows that it expects global electricity generation to rise by 2,493TWh between 2022 and 2025.

> The IEA expects the growth in renewable generation to cover the vast majority of this total, growing by 2,450TWh. This is equivalent to 98% of the overall increase in global demand.

https://www.commondreams.org/news/fossil-fuels-global-energy...

Fossil Fuels Made Up 82% of Global Energy Consumption in 2022: New Data

Data published Monday shows that fossil fuels made up 82% of global energy consumption in 2022, another indication that the global transition away from planet-warming sources is moving far too slowly as rich nations continue burning oil, gas, and coal at an unsustainable pace.

“Despite further strong growth in wind and solar in the power sector, overall global energy-related greenhouse gas emissions increased again," said Davenport. "We are still heading in the opposite direction to that required by the Paris Agreement."

2/3rds of that fossil fuels becomes wasted heat. We only need to replace the third that actually performs useful functions.

Even if the plants were cost competitive, which they are not, the existing ones are only built to last 30-50 years which means they'll age out and be replaced by renewables on that timescale at the very worst.

That doesn't consider different energy use cases, existing infrastructure, and increasing global energy demands, which could require more than simply replacing the 'useful' energy currently obtained from fossil fuels.

Electricity generation (coal) ... 33-40% efficiency

Electricity generation (nat. gas) ... 50-60%

Heating (nat. gas.) ... upto 97%

Transportation ... 20-30%

Industrial ... cement for example at about 50%

What am I missing? Got any links or references for "we only need to replace the third"?

This works through examples with numbers:

https://ourworldindata.org/energy-substitution-method

Also note that heat pump based heating can be 5x as efficient as nat gas heating. Which means using gas to generate electricity to run heat pumps is an improvement.

edit to add: also note that the oldest, dirtiest and least efficient plants will get shut first, having an outsized impact.

Share some figures that are per dollar. Fusion has the potential to beat all of that.

I don't understand what you mean?

Any future fusion that requires a steam turbine to generate electricity will not be cost competitive with wind/solar/batteries by the time it arrives as the steam turbine will cost more to build and maintain than the alternatives even if you assume the fusion part is free.

Some fusion approaches convert more directly to electricity and might make a difference, but probably not for decades.

Sure, with the first working protype in 2043, and global deployment of 10,000 working plants by 2063.

What's happening in the meantime?

TISM

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