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We are comparing two energy sources: one where output depends on the weather, and can go to near 0 another where output is strictly predictable but takes time

We are comparing two energy sources: one where output depends on the weather, and can go to near 0 another where output is strictly predictable but takes time to change. Option 2 have the problem of oversupply and undersupply. This forces either storage or fossil fuels in the picture. Option 1, however, only deals with oversupply, which does not require expensive mitigations. Not obvious why option 2 is preferable here

Retric 8y ago
First, you can go off grid using 100% solar and a relatively small battery system as long as you get enough solar cells. The reason this works is your daytime input never drops to 0 and it's generally lower when you need less energy for AC systems. In terms of the grid, Wind and solar really can't go to 0 over large areas. The minimum vs maximum output shows high variance, but maximum output is largely irrelevant. Really what you care about is minimum vs average output and that's more narrow band than you might think. Even better by locating Wind / Solar you can more closely match your daily demand curve. Option 1, costs far more per kWh even if you can use every kWh, it's just get's worse from there. As it still needs over supply as power plants need occasional maintenance and the grid maximum and minimum demand over a year are wildly separated. You can setup maintenance around peak annual demands, but even then you will have occasional unexpected shutdowns.
- korantu 8y ago
  Majority of energy consumption and population happens in cities / industry, so if we are talking significant co2 soonest, we should really focus on these. For large consumers like these to go solar/wind, you will have to really over-provision solar/wind so that minimum possible power output is still enough. (Calm night, anyone?) This looks highly inefficient and tough to predict. Whereas nuclear can and are already operating in load following mode routinely: [1] [1] http://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf http://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-loa...
  - Retric 8y ago
    First, most city’s have a lot of space for solar and can easily import wind power. ~66w/m2 average over 24 hours is 66 MW per km^2 / the percentage covered in panels and really adds up. Wind really can't be calm for long periods over large areas because large areas will always have temperatures differences. It's like saying what if the sun does not rise tomorrow? If that's actually happening you have much bigger problems. Load following nuclear power plants become even more expensive. Not a huge deal on nuclear subs, but a major issue for civilian infrastructure. Just like energy storage they simply increase the cost of energy above alternatives. PS: Now if you could get nuclear without any form of subsides down to about 2.5c/kWh then running 24/7 or peaking power with average load's of around 30% down at around 8c/kWh then I would agree it had a major place. But, it's just no where near those numbers.

Retric 8y ago

First, you can go off grid using 100% solar and a relatively small battery system as long as you get enough solar cells. The reason this works is your daytime input never drops to 0 and it's generally lower when you need less energy for AC systems. In terms of the grid, Wind and solar really can't go to 0 over large areas. The minimum vs maximum output shows high variance, but maximum output is largely irrelevant. Really what you care about is minimum vs average output and that's more narrow band than you might think. Even better by locating Wind / Solar you can more closely match your daily demand curve. Option 1, costs far more per kWh even if you can use every kWh, it's just get's worse from there. As it still needs over supply as power plants need occasional maintenance and the grid maximum and minimum demand over a year are wildly separated. You can setup maintenance around peak annual demands, but even then you will have occasional unexpected shutdowns.

korantu 8y ago
Majority of energy consumption and population happens in cities / industry, so if we are talking significant co2 soonest, we should really focus on these. For large consumers like these to go solar/wind, you will have to really over-provision solar/wind so that minimum possible power output is still enough. (Calm night, anyone?) This looks highly inefficient and tough to predict. Whereas nuclear can and are already operating in load following mode routinely: [1] [1] http://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf http://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-loa...
- Retric 8y ago
  First, most city’s have a lot of space for solar and can easily import wind power. ~66w/m2 average over 24 hours is 66 MW per km^2 / the percentage covered in panels and really adds up. Wind really can't be calm for long periods over large areas because large areas will always have temperatures differences. It's like saying what if the sun does not rise tomorrow? If that's actually happening you have much bigger problems. Load following nuclear power plants become even more expensive. Not a huge deal on nuclear subs, but a major issue for civilian infrastructure. Just like energy storage they simply increase the cost of energy above alternatives. PS: Now if you could get nuclear without any form of subsides down to about 2.5c/kWh then running 24/7 or peaking power with average load's of around 30% down at around 8c/kWh then I would agree it had a major place. But, it's just no where near those numbers.