5 ms·

While it's clear that nuclear is uneconomical now and in the near future, it's still not quite clear to me if we can do without it. Solar and wind are great, c

by GlennS 9y ago

While it's clear that nuclear is uneconomical now and in the near future, it's still not quite clear to me if we can do without it. Solar and wind are great, cheap options right now, and they've really outperformed what people expected over the past few years. Is there enough potential capacity of solar + wind + hydro to meet total future demand though? Are we going to run out of land and coast first? If we're going to reduce our carbon emissions enough by 2050, we need to electrify heating, industry and transport. That's going to increase electricity demand by a lot. Carbon capture and storage is pretty clearly dead. Tidal lagoons seem like they're also just too expensive. Neither fusion nor alternative fission technologies will be up and running in time to make much difference to the 2050 target for 80% reduction from 1990 levels (UK specific).

hanbura 9y ago
We could provide the world's total energy needs by covering a small portion of the Sahara desert with solar. We are not running out of land anytime soon. There is also a practical limit where wind energy takes too much energy out of weather systems, affecting climate, but that point is also far beyond the current world energy usage. We're not running out of renewable energy anytime soon.
- isostatic 9y ago
  A single hurricane produces about 200 times the global energy use per year. We're not able to extract power from the atmosphere to make a dent.
- deleted 9y ago
  [deleted]
- smitherfield 9y ago
  >We could provide the world's total energy needs by covering a small portion of the Sahara desert with solar. The Sahara desert is extremely sandy, and extremely windy, which makes it a pretty terrible, or at least prohibitively-expensive place to build a solar farm. It is also extremely complicated and extremely expensive to transmit large amounts of power over long distances, particularly across national borders (everyone's on a different AC standard), particularly across many national borders.
  - Reason077 9y ago
    It's not really that complicated or that expensive to move power over long distances via HVDC interconnects. China has many overland HVDC links, some thousands of km long and with huge capacities, to move renewable energy from inland areas to the coast. The UK and Iceland are considering an undersea HVDC interconnector more than 1000 km long. The distance between potential solar array sites in the northern Sahara and the electrical grids in Southern Europe are considerably less than this.
    - lmm 9y ago
      > The UK and Iceland are considering an undersea HVDC interconnector more than 1000 km long. At an estimated cost of about 3 billion, for less than 1/3 the capacity of this power station.
      - Reason077 9y ago
        Icelink's estimated cost is about £2.4b, which would be shared by both sides. Hinkley C's construction cost is £20.3b, and the cost to UK consumers over the plant's lifetime exceeds £50b.
Latty 9y ago
Is there really a concern about running out of land/coast for power generation? I feel like there is a lot of space left. The bigger issue to me seems to be the move from production we can control to production on nature's schedule. Nuclear plants can "just" "throw another rod in" and generate power as needed. The promise there appears to be a distributed approach. Getting people installing batteries in homes as standard could make it so buying electricity when it's being produced rather than when you need it is the norm. The economics incentivise this and hopefully the tech is getting there. Combine that with the likely move to everyone having an electric car (read: giant battery) sat on their drive doing the same thing half the time, and maybe that problem is being solved.
- seanmcdirmid 9y ago
  I don’t think nuclear power is that on demand, can you really just throw a rod in when starting and stopping the plant is so expensive?
  - hanbura 9y ago
    You can regulate a nuclear plant between ~50% and 100% output in a matter of minutes by adjusting the control rods. That's very limited compared to most other options, but obviously much better than solar or wind.
    - isostatic 9y ago
      And far worse than batteries
      - seanmcdirmid 9y ago
        Batteries, like hydro reservoirs, can be charged from inflexible energy sources when they have surplus output. It really isn’t fair to compare them to energy sources as they can smooth over the inflexible ones.
        9y ago
isostatic 9y ago
Wind at say 1GW in 200 square miles (dogged bank figures) Total sea area therefore is 1 million gw or 1,000tw, or 24ktwh/ day Need 200k twh for global energy usage, with 30% to spare Wind loading of average 25%, you need to cover less than 10% of the sea area to produce enough evergy to replace every form of power on the planet - not just electricity.
- seszett 9y ago
  10% of the sea is absolutely huge though. On land, it's the area of Russia, Canada and the US, completely covered with wind farms.
  - isostatic 9y ago
    That's for the entire global energy production (and then some), including transport, heating, industry, not just electricity. 10% of land is set aside for agriculture, which is about 1/3 of 10% of water, but gives an indication. That's an area far larger than the entire US (including Alaska). We use a lot of space. But you wouldn't produce your entire output from wind. In a desert you get about 2kwh per day from solar per square metre, or 2gwh per square km, or 100,000 SQkm of land for solar. That's under half the size of Arizona's desert, or 1% of Sahara.
nl 9y ago
Is there enough potential capacity of solar + wind + hydro to meet total future demand though? Yes. And very easily too. ANU did a study in Australia and found pump hydro could cover 100% of the supply needs while only using a small fraction of available sites. Australia is a very flat country so I'd imagine it is even easier in most countries. See http://www.anu.edu.au/news/all-news/anu-finds-22000-potential-pumped-hydro-sites-in-australia http://www.anu.edu.au/news/all-news/anu-finds-22000-potentia...
- ben_w 9y ago
  Australia is also very large and very low population. Less than 2/3rds the population of California but about 18 times the area.
  - nl 9y ago
    That shouldn't really matter. It was something like 1% (?) of the available sites to make Australia 100% renewable. So in the US it might be 15% - except that the US has a lot more mountains and a lot more water near population centers.

by GlennS 9y ago

hanbura 9y ago

We could provide the world's total energy needs by covering a small portion of the Sahara desert with solar. We are not running out of land anytime soon. There is also a practical limit where wind energy takes too much energy out of weather systems, affecting climate, but that point is also far beyond the current world energy usage. We're not running out of renewable energy anytime soon.

isostatic 9y ago
A single hurricane produces about 200 times the global energy use per year. We're not able to extract power from the atmosphere to make a dent.
deleted 9y ago
[deleted]
smitherfield 9y ago
>We could provide the world's total energy needs by covering a small portion of the Sahara desert with solar. The Sahara desert is extremely sandy, and extremely windy, which makes it a pretty terrible, or at least prohibitively-expensive place to build a solar farm. It is also extremely complicated and extremely expensive to transmit large amounts of power over long distances, particularly across national borders (everyone's on a different AC standard), particularly across many national borders.
- Reason077 9y ago
  It's not really that complicated or that expensive to move power over long distances via HVDC interconnects. China has many overland HVDC links, some thousands of km long and with huge capacities, to move renewable energy from inland areas to the coast. The UK and Iceland are considering an undersea HVDC interconnector more than 1000 km long. The distance between potential solar array sites in the northern Sahara and the electrical grids in Southern Europe are considerably less than this.
  - lmm 9y ago
    > The UK and Iceland are considering an undersea HVDC interconnector more than 1000 km long. At an estimated cost of about 3 billion, for less than 1/3 the capacity of this power station.
    - Reason077 9y ago
      Icelink's estimated cost is about £2.4b, which would be shared by both sides. Hinkley C's construction cost is £20.3b, and the cost to UK consumers over the plant's lifetime exceeds £50b.

Latty 9y ago

Is there really a concern about running out of land/coast for power generation? I feel like there is a lot of space left. The bigger issue to me seems to be the move from production we can control to production on nature's schedule. Nuclear plants can "just" "throw another rod in" and generate power as needed. The promise there appears to be a distributed approach. Getting people installing batteries in homes as standard could make it so buying electricity when it's being produced rather than when you need it is the norm. The economics incentivise this and hopefully the tech is getting there. Combine that with the likely move to everyone having an electric car (read: giant battery) sat on their drive doing the same thing half the time, and maybe that problem is being solved.

seanmcdirmid 9y ago
I don’t think nuclear power is that on demand, can you really just throw a rod in when starting and stopping the plant is so expensive?
- hanbura 9y ago
  You can regulate a nuclear plant between ~50% and 100% output in a matter of minutes by adjusting the control rods. That's very limited compared to most other options, but obviously much better than solar or wind.
  - isostatic 9y ago
    And far worse than batteries
    - seanmcdirmid 9y ago
      Batteries, like hydro reservoirs, can be charged from inflexible energy sources when they have surplus output. It really isn’t fair to compare them to energy sources as they can smooth over the inflexible ones.
      - 9y ago

isostatic 9y ago

Wind at say 1GW in 200 square miles (dogged bank figures) Total sea area therefore is 1 million gw or 1,000tw, or 24ktwh/ day Need 200k twh for global energy usage, with 30% to spare Wind loading of average 25%, you need to cover less than 10% of the sea area to produce enough evergy to replace every form of power on the planet - not just electricity.

seszett 9y ago
10% of the sea is absolutely huge though. On land, it's the area of Russia, Canada and the US, completely covered with wind farms.
- isostatic 9y ago
  That's for the entire global energy production (and then some), including transport, heating, industry, not just electricity. 10% of land is set aside for agriculture, which is about 1/3 of 10% of water, but gives an indication. That's an area far larger than the entire US (including Alaska). We use a lot of space. But you wouldn't produce your entire output from wind. In a desert you get about 2kwh per day from solar per square metre, or 2gwh per square km, or 100,000 SQkm of land for solar. That's under half the size of Arizona's desert, or 1% of Sahara.

nl 9y ago

Is there enough potential capacity of solar + wind + hydro to meet total future demand though? Yes. And very easily too. ANU did a study in Australia and found pump hydro could cover 100% of the supply needs while only using a small fraction of available sites. Australia is a very flat country so I'd imagine it is even easier in most countries. See http://www.anu.edu.au/news/all-news/anu-finds-22000-potential-pumped-hydro-sites-in-australia http://www.anu.edu.au/news/all-news/anu-finds-22000-potentia...

ben_w 9y ago
Australia is also very large and very low population. Less than 2/3rds the population of California but about 18 times the area.
- nl 9y ago
  That shouldn't really matter. It was something like 1% (?) of the available sites to make Australia 100% renewable. So in the US it might be 15% - except that the US has a lot more mountains and a lot more water near population centers.