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Sustainable Energy without the Hot Air (Revised, Community Edition)

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Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#41

Post by mcot2 »

algo_trader wrote: post #7
wiz21c wrote: post #4

Earlier quoted context omitted.

FTBook: > Wind turbines are getting bigger all the time. Do bigger wind turbines change this chapter’s answer? > Chapter B explains. Bigger wind turbines deliver financial economies of scale, but they don’t greatly increase the total power per unit land area, because bigger windmills have to be spaced further apart. A wind farm that’s twice as tall will deliver roughly 30% more power. So, did wind turbine production…

Amazingly, yes! Turbines have gone from 1-2MW to 10-16MW Capacity factors have gone from 20% to 50%-60% Annual additions gave gone from sub-GW to 70GW last year And with turbine spacing of 1km you can actually do stuff with the land in between. On the other hand, transmission projects still take 10-20 years, and new transmission projects are often over booked by 300%-400% before they are even started.

Yes, very good point. Renewable enegry generation really isn’t the struggle these days, it is transmission from areas with high solar and wind potential to areas with less viable solar and wind production.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#42

Post by kergonath »

jetbooster wrote: post #35
kergonath wrote: post #31

Earlier quoted context omitted.

Getting rid of parking lots (and the energy- and ressources-hungry individual cars sitting on them) would certainly be a big step forward to a sustainable future.

I don't think they were suggesting getting rid of the the car parks, but rather putting solar over the top of them. Which would also reduce the amount of petrol used to AC the car when you get back in it too (though this effect is probably negligible)

I don’t think they did, either. Nevertheless, cars are a huge waste of ressources and energy and there is no realistic path to net zero in the next half century without a significant reduction in consumption. Electric cars or not.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#43

Post by derriz »

cbmuser wrote: post #21
derriz wrote: post #15

Earlier quoted context omitted.

The issue is that we now have real experience of deploying this stuff at scale and integrating intermittent sources into grids. Many countries in Europe have 30% or more of their electricity supplied by intermittent but it turns out that the integration problem isn't as difficult as envisaged. The consensus amongst engineers is that up to about 70% is manageable without any big tech breakthroughs. Network reliability…

Germany has a large share (50%) of renewables and their specific CO2 emissions per kWh are up to ten times higher as compared to France with 70% nuclear. Volatile renewables don’t effectively help to reduce greenhouse gas emissions. https://ourworldindata.org/grapher/ghg-emissions-by-sector?t...

"Volatile" renewables absolutely do help reduce greenhouse gas emissions.

As the renewables share of generation has been increasing, the CO2 intensity of electricity generation in Germany has dropped from 542gCO2/kWh in 2000 to 296gCO2/kWh in 2020[1].

Btw, your link brings me to a table on agricultural CO2 emissions?

[1] https://www.iea.org/data-and-statistics/charts/development-o...

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#44

Post by aborsy »

Before research into sustainable energy, David MacKay had rediscovered Low Density Parity Check (LDPC) codes in early 90s, perhaps the most common type of error correction codes used nowadays in commercial systems (alongside with Reed Solomon codes used for storage).

He then worked on sustainable energy long before it became fashionable.

His early death was a significant loss. He blogged cheerfully from hospital til few days before his death

http://itila.blogspot.com/2016/04/perhaps-my-last-post-well-...

Rest In Peace David MacKay.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#45

Post by tito »

ycomb-uit-co-uk wrote: post #6

Have a look at http://2050-calculator-tool.decc.gov.uk/ (I was David's Editor for "Sustainable Energy - without the hot air". There's been quite a bit of interest in updating the book, but there are obvious difficulties. If have suggestions, let me know. Niall Mansfield sewtha-2.0@uit.co.uk )

Rufus, terrific work here!

Niall - great to see you here. My mind goes towards helping others with "powers of 10 math" about climate. SWITHA for me embodied this concept of "how to think about the climate" more than anything.

That type of thinking is needed more now than ever. Even that line "2 billion years of energy reserves", so powerful.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#46

Post by derriz »

DennisP wrote: post #18
derriz wrote: post #15

Earlier quoted context omitted.

The issue is that we now have real experience of deploying this stuff at scale and integrating intermittent sources into grids. Many countries in Europe have 30% or more of their electricity supplied by intermittent but it turns out that the integration problem isn't as difficult as envisaged. The consensus amongst engineers is that up to about 70% is manageable without any big tech breakthroughs. Network reliability…

Fossil backup isn't tenable past 2050 at the latest.

Agreed.

But assuming no technology advances in this area for 30 years time seems implausible. What has happened with price/efficiency of solar, wind and grid-scale batteries in the last 10 years provides a lesson. None of these were practical even 10 years ago and now they represent 90% of newly installed capacity globally (2020). And this is happening all-over whether with or without government support.

For example, new-build, grid-scale battery storage is now cheaper on an LCOE basis than new build open-cycle ("peaker") natural gas plants. This has only happened recently - about a year ago. I was completely skeptical that this could happen a few years ago.

I urge any/all hackernews readers to read more about _recent_ developments in de-carbonizing energy. It's fascinating and it has become clear to me that we're living through one of the great technology revolutions of human history. It genuinely is a Kodak/smartphone type moment with even bigger implications for human wellbeing.

It's amazing that by being cheap enough, all the disadvantages of a new technology become less relevant. A bit like how the PC displaced "real computers" (i.e. mainframes) even though at the time they were little more than microcontrollers integrated with a terminal.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#47

Post by ben_w »

kergonath wrote: post #30
542458 wrote: post #11

One thing that feels a bit strange to me is that he uses timelines of 1000 years when calculating nuclear reserves. I don’t believe we need a plan for the next 1000 years - think of what our understanding of power generation and transmission was a millennium ago. Assuming that we will still be using the same technologies in 1000 years seems a bit pessimistic to me.

> One thing that feels a bit strange to me is that he uses timelines of 1000 years when calculating nuclear reserves. Not really. Uranium and thorium are insanely energy dense and whilst it’s obviously impossible to predict energy use a millenium from now, it could handle more than a couple of centuries of exponential growth of energy consumption. Then there are things like fuels made of natural isotopes (so no enric…

> it could handle more than a couple of centuries of exponential growth of energy consumption.

That rather depends on the exponent and the time period. The minimum for “a couple of centuries” is 200 years: 1%/year for 200 years? Sure; 1%/year for 1000 years or 5%/year for 200 years? 2-2.5 times global solar irradiance. I think that’s enough to raise the temperature to boiling, and I don’t think there’s enough nuclear fuel to do that (but I could be wrong about both).

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#48

Post by ben_w »

cbmuser wrote: post #19
542458 wrote: post #11

One thing that feels a bit strange to me is that he uses timelines of 1000 years when calculating nuclear reserves. I don’t believe we need a plan for the next 1000 years - think of what our understanding of power generation and transmission was a millennium ago. Assuming that we will still be using the same technologies in 1000 years seems a bit pessimistic to me.

Physics won’t change in a thousand years and it’s very unlikely we’ll find anything more powerful and energy-dense beyond nuclear fission and fusion.

On that timescale I expect us to engineer antimatter-based energy storage. Or do something literally incomprehensible — a thousand years ago we didn’t have the language to describe the language to describe relativity.
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