4 ms·

Interesting that this is achieved with only a 5% overbuild. The simulations I have seen to get to 100% for Europe and North America without long term storage h

Interesting that this is achieved with only a 5% overbuild. The simulations I have seen to get to 100% for Europe and North America without long term storage have used a 200% (aka 3X) overbuild. Probably partially due to Australia being a good place for sun and wind, and partially for targeting 99% rather than 100%.

hfucvyv 3y ago
[dead]
pfdietz 3y ago
If they are using peakers for the last 1%, one can instead fuel those peakers with e-fuels. The low round trip efficiency of e-fuels doesn't matter much if they're providing just 1% of the total.
hackerlight 3y ago
That could be the difference between "near 100%" and 100%. Or it could be because Australia has good renewable resources. This paper is a similar analysis but for the US, check Fig. 3. As you go from 97% to 100% renewables, the overbuilding requirements blow up. https://sci-hub.se/10.1039/c7ee03029k https://sci-hub.se/10.1039/c7ee03029k
- pfdietz 3y ago
  That conclusion assumes no long term storage. Including hydrogen drastically reduces the overbuilding required. Put another way: if you overbuilt that much, you can make hydrogen for basically the cost of the electrolysers, since the input power is often free.
  - gwright 3y ago
    You are correct that you can't create a stable, resilient grid just with intermittent renewables, you need storage. But I don't think anyone has demonstrated long-term storage at grid scale, capable of storing power across seasons, which is needed in many areas. To be feasible the storage system has to be cheaper than maintaining some fossil fuel plants. I haven't seen much about promising hydrogen storage systems.
    - pfdietz 3y ago
      > But I don't think anyone has demonstrated Arguments like this really annoy me, if it's clear there's not a serious obstacle. It's just a "nothing can be done for the first time" argument.
      - gwright 3y ago
        I'm not saying it can't be done. I'm saying it hasn't been done yet. How about we try it before pretending that we can shift to 100% renewables or before legislating transitions that we don't know how to accomplish. Hawaii is trying hard, but it doesn't seem to be going well with the grid becoming less reliable. BTW, this video is a solid overview of the power situation in Hawaii: https://www.youtube.com/watch?v=bbECmVdyWlQ&themeRefresh=1 https://www.youtube.com/watch?v=bbECmVdyWlQ&themeRefresh=1 I believe parts of the Azores have tried, but have not been successful. I would be very interested in pointers to successful projects in this area.
        hackerlight 3y ago
        I don't like how we talk about 100% renewables as if failing that means failure. I'm happy with 90% renewables, a much easier goal, while we figure out the diminishing marginal returns later as technology breakthroughs and cost curves do the work for us. Our objective is to minimize the area under the curve of future emissions. It's not "net-zero" in the abstract. Net-zero is just a proxy for the true objective. Getting to 90% renewables soon means less emissions (while being cheaper) than waiting an extra 10-15 years for 100% nuclear.
        gwright 3y ago
        I'm not entirely sure what you mean by 90%. 90% of what? You can't just have 90% of power generated by renewables and 10% by fossil fuels because there are times when you get 0% from renewables and so your fossil fuel plants need to provide 100% of the power. So you spent all that money on renewable infrastructure and didn't even get the benefit of shuttering your fossil fuel plants.
  - pjc50 3y ago
    > basically the cost of the electrolysers Yes, that's the expensive bit. The reason you don't get much of this already is exactly that the capital cost of electrolysers is very high because of the requirement for platinum electrodes. And big capital investments are not free.
    - pfdietz 3y ago
      Platinum isn't required for alkaline electrolysis.
    - adrianN 3y ago
      The reason we don't have a lot of hydrogen right know is because we don't have a lot of surplus energy right now. It makes no sense to buy expensive equipment and run in only a few hundred hours a year.
      - pfdietz 3y ago
        We have huge amounts of hydrogen right now. At standard temperature and pressure, the amount of hydrogen made globally each year would occupy 700 cubic kilometers of volume. It's just that it's made overwhelmingly from fossil fuels, mostly natural gas (6% of global gas production goes to making hydrogen). That this is being done instead of making green hydrogen is because CO2 from the fossil fuel process is not being taxed or otherwise forced to account for the negative externalities. This also illustrates that producing hydrogen without CO2 release is not an optionally solvable problem. Without the ammonia made from hydrogen (which is where most of it is going) billions will starve.
mnw21cam 3y ago
The article itself makes the point that overbuilding the renewables massively will get you from 98% to 100%, but the consequences of that are increased cost and increased emissions, compared to just having some fossil-fueled peaker generation on standby.
- ZeroGravitas 3y ago
  Some of the US government plans involve getting to 95% carbon free electricity, then refocussing investment to electrifying anything that still uses fossil fuels as the cost/benefit will have tilted dramatically at that point, even for the harder to electrify sectors, and provide more bang for buck than fretting about the last percent of peaker plants.
cinntaile 3y ago
The numbers I have seen assign a capacity factor of 0.1 for renewables, that would require 900% overbuild.
troupo 3y ago
> The simulations I have seen to get to 100% for Europe and North America without long term storage have used a 200% (aka 3X) overbuild. You don't need simulations. Right now solar+wind in Germany is at capacity that is 2x Germany's consumption. Almost every day (and definitely every night) they burn coal and import electricity from other countries because, you know, night happens, cloudy days happen, quiet days with little to no wind happen.
- adrianN 3y ago
  I thought overbuild figures usually include capacity factors, putting Germany at something like 0.3x instead of 2x?
  - gwright 3y ago
    My guess is that a power grid engineer would include capacity factors, but I've never seen the mass media, politicians, or advocacy groups think like an engineer in this regard. Even making that adjustment it doesn't factor in seasonal variations. Not understanding these factors results in ignorant headlines like: California just ran on 100% renewable energy, but fossil fuels aren't fading away yet https://www.npr.org/2022/05/07/1097376890/for-a-brief-moment-calif-fully-powered-itself-with-renewable-energy https://www.npr.org/2022/05/07/1097376890/for-a-brief-moment... Renewables are now way cheaper than coal https://energynews.us/newsletter/renewables-are-now-way-cheaper-than-coal/ https://energynews.us/newsletter/renewables-are-now-way-chea...
- deleted 3y ago
  [deleted]
- hackerlight 3y ago
  That's because they haven't done much storage yet. Which is to be expected, you want to leave that for the end because it's the most expensive bit. They're planning 15GW of 4-hour batteries by 2030. https://blog.fluenceenergy.com/energy-storage-roll-out-can-save-german-energy-consumers-12-billion-euros https://blog.fluenceenergy.com/energy-storage-roll-out-can-s...
ZeroGravitas 3y ago
I think it's mostly that overbuild is usually referring to capacity, and they've multiplied the generation. I'd guess this works out roughly the same if you applied his scaling factors to the current capacity. His 25% rooftop solar would be around 200% capacity given a 12% capacity factor.

hfucvyv 3y ago

[dead]

pfdietz 3y ago

If they are using peakers for the last 1%, one can instead fuel those peakers with e-fuels. The low round trip efficiency of e-fuels doesn't matter much if they're providing just 1% of the total.

hackerlight 3y ago

That could be the difference between "near 100%" and 100%. Or it could be because Australia has good renewable resources. This paper is a similar analysis but for the US, check Fig. 3. As you go from 97% to 100% renewables, the overbuilding requirements blow up. https://sci-hub.se/10.1039/c7ee03029k https://sci-hub.se/10.1039/c7ee03029k

pfdietz 3y ago
That conclusion assumes no long term storage. Including hydrogen drastically reduces the overbuilding required. Put another way: if you overbuilt that much, you can make hydrogen for basically the cost of the electrolysers, since the input power is often free.
- gwright 3y ago
  You are correct that you can't create a stable, resilient grid just with intermittent renewables, you need storage. But I don't think anyone has demonstrated long-term storage at grid scale, capable of storing power across seasons, which is needed in many areas. To be feasible the storage system has to be cheaper than maintaining some fossil fuel plants. I haven't seen much about promising hydrogen storage systems.
  - pfdietz 3y ago
    > But I don't think anyone has demonstrated Arguments like this really annoy me, if it's clear there's not a serious obstacle. It's just a "nothing can be done for the first time" argument.
    - gwright 3y ago
      I'm not saying it can't be done. I'm saying it hasn't been done yet. How about we try it before pretending that we can shift to 100% renewables or before legislating transitions that we don't know how to accomplish. Hawaii is trying hard, but it doesn't seem to be going well with the grid becoming less reliable. BTW, this video is a solid overview of the power situation in Hawaii: https://www.youtube.com/watch?v=bbECmVdyWlQ&themeRefresh=1 https://www.youtube.com/watch?v=bbECmVdyWlQ&themeRefresh=1 I believe parts of the Azores have tried, but have not been successful. I would be very interested in pointers to successful projects in this area.
      - hackerlight 3y ago
        I don't like how we talk about 100% renewables as if failing that means failure. I'm happy with 90% renewables, a much easier goal, while we figure out the diminishing marginal returns later as technology breakthroughs and cost curves do the work for us. Our objective is to minimize the area under the curve of future emissions. It's not "net-zero" in the abstract. Net-zero is just a proxy for the true objective. Getting to 90% renewables soon means less emissions (while being cheaper) than waiting an extra 10-15 years for 100% nuclear.
        gwright 3y ago
        I'm not entirely sure what you mean by 90%. 90% of what? You can't just have 90% of power generated by renewables and 10% by fossil fuels because there are times when you get 0% from renewables and so your fossil fuel plants need to provide 100% of the power. So you spent all that money on renewable infrastructure and didn't even get the benefit of shuttering your fossil fuel plants.
- pjc50 3y ago
  > basically the cost of the electrolysers Yes, that's the expensive bit. The reason you don't get much of this already is exactly that the capital cost of electrolysers is very high because of the requirement for platinum electrodes. And big capital investments are not free.
  - pfdietz 3y ago
    Platinum isn't required for alkaline electrolysis.
  - adrianN 3y ago
    The reason we don't have a lot of hydrogen right know is because we don't have a lot of surplus energy right now. It makes no sense to buy expensive equipment and run in only a few hundred hours a year.
    - pfdietz 3y ago
      We have huge amounts of hydrogen right now. At standard temperature and pressure, the amount of hydrogen made globally each year would occupy 700 cubic kilometers of volume. It's just that it's made overwhelmingly from fossil fuels, mostly natural gas (6% of global gas production goes to making hydrogen). That this is being done instead of making green hydrogen is because CO2 from the fossil fuel process is not being taxed or otherwise forced to account for the negative externalities. This also illustrates that producing hydrogen without CO2 release is not an optionally solvable problem. Without the ammonia made from hydrogen (which is where most of it is going) billions will starve.

mnw21cam 3y ago

The article itself makes the point that overbuilding the renewables massively will get you from 98% to 100%, but the consequences of that are increased cost and increased emissions, compared to just having some fossil-fueled peaker generation on standby.

ZeroGravitas 3y ago
Some of the US government plans involve getting to 95% carbon free electricity, then refocussing investment to electrifying anything that still uses fossil fuels as the cost/benefit will have tilted dramatically at that point, even for the harder to electrify sectors, and provide more bang for buck than fretting about the last percent of peaker plants.

cinntaile 3y ago

The numbers I have seen assign a capacity factor of 0.1 for renewables, that would require 900% overbuild.

troupo 3y ago

> The simulations I have seen to get to 100% for Europe and North America without long term storage have used a 200% (aka 3X) overbuild. You don't need simulations. Right now solar+wind in Germany is at capacity that is 2x Germany's consumption. Almost every day (and definitely every night) they burn coal and import electricity from other countries because, you know, night happens, cloudy days happen, quiet days with little to no wind happen.

adrianN 3y ago
I thought overbuild figures usually include capacity factors, putting Germany at something like 0.3x instead of 2x?
- gwright 3y ago
  My guess is that a power grid engineer would include capacity factors, but I've never seen the mass media, politicians, or advocacy groups think like an engineer in this regard. Even making that adjustment it doesn't factor in seasonal variations. Not understanding these factors results in ignorant headlines like: California just ran on 100% renewable energy, but fossil fuels aren't fading away yet https://www.npr.org/2022/05/07/1097376890/for-a-brief-moment-calif-fully-powered-itself-with-renewable-energy https://www.npr.org/2022/05/07/1097376890/for-a-brief-moment... Renewables are now way cheaper than coal https://energynews.us/newsletter/renewables-are-now-way-cheaper-than-coal/ https://energynews.us/newsletter/renewables-are-now-way-chea...
deleted 3y ago
[deleted]
hackerlight 3y ago
That's because they haven't done much storage yet. Which is to be expected, you want to leave that for the end because it's the most expensive bit. They're planning 15GW of 4-hour batteries by 2030. https://blog.fluenceenergy.com/energy-storage-roll-out-can-save-german-energy-consumers-12-billion-euros https://blog.fluenceenergy.com/energy-storage-roll-out-can-s...

ZeroGravitas 3y ago

I think it's mostly that overbuild is usually referring to capacity, and they've multiplied the generation. I'd guess this works out roughly the same if you applied his scaling factors to the current capacity. His 25% rooftop solar would be around 200% capacity given a 12% capacity factor.