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This is what the sky looked like the last time there were more than three days over 40C in a row in Melbourne: https://i.insider.com/5dfc7162e94e8636622f1667 ht

This is what the sky looked like the last time there were more than three days over 40C in a row in Melbourne: https://i.insider.com/5dfc7162e94e8636622f1667 https://i.insider.com/5dfc7162e94e8636622f1667 It is also somewhat difficult to use solar power for cooling at midnight when it's still 35C.

bryanlarsen 3y ago
It's super easy. Cool to 20C during the day and close your windows. In the morning you should be well under 22C. I can do the inverse: warm my house to 22C and turn off the furnace overnight when it's -30C. The house won't drop below 20C. And that's a 50C differential. A 14C differential is trivial in comparison.
- llm_trw 3y ago
  So you have thousands of dollars worth of insulation because you live in an arctic climate. Congratulations I suppose. Now instead of just spending hundreds of billions on building a new grid Australians will also have to spend hundreds of billions on insulating their houses.
  - troupo 3y ago
    To be completely honest, they probably should, and people don't talk enough about proper insulation regardless of the region. E.g. in colder climates many modern buildings are just hermetically sealed boxes with issues around CO2 levels etc.
  - bryanlarsen 3y ago
    For a 14C differential you don't need insulation, you just need to seal leaks.
    - throw0101b 3y ago
      > For a 14C differential you don't need insulation, you just need to seal leaks. And hope that your inside air temperature is not at the dew point of the hot, humid air that is outside (thus causing condensation).
      - adrianN 3y ago
        If your house had problems with condensation forming on the outside then I hope it never rains where you are.
        throw0101b 3y ago
        Water in liquid form (e.g., rain) will (mostly!) go down with gravity, and so overhangs will help a lot, as will proper grade sloping away from your foundations. Water in vapour form will be more diffuse and be everywhere the air is. Further, your cladding / water control layer (which deals with rain (and UV)) generally needs to be open to air so that it can dry properly: * https://en.wikipedia.org/wiki/Rainscreen https://en.wikipedia.org/wiki/Rainscreen so that can lead to moist air getting places that water may not, and if you don't have insulation between the warm-moist outside and the cool-dry inside: * https://buildingscience.com/documents/insights/bsi-001-the-perfect-wall https://buildingscience.com/documents/insights/bsi-001-the-p... problems can start.
hackerlight 3y ago
The picture in my mind was: You have overbuilt solar charging nearby batteries (lithium ion, sodium ion, whatever) to cover the 4-hour busy period at night, and smaller amounts of longer duration storage like pumped hydro to cover the quieter periods after 10pm. I'm not sure if that'd work out to be cheaper than doing the proposed 60% wind/45% solar mix with inter-state transmission. It would reduce the need for new transmission lines, though.
Retric 3y ago
Aka, really sunny just as suggested. Cooling at night requires batteries, but their cost is offset by how cheap they are to charge with excess solar resulting in positive feedback loops. Further, AC needs to work far less hard at night as you avoid solar gain through windows etc, fewer devices are on reducing heat gain, outside temperature drop further reducing heat gain while also increasing AC efficiency.

bryanlarsen 3y ago

It's super easy. Cool to 20C during the day and close your windows. In the morning you should be well under 22C. I can do the inverse: warm my house to 22C and turn off the furnace overnight when it's -30C. The house won't drop below 20C. And that's a 50C differential. A 14C differential is trivial in comparison.

llm_trw 3y ago
So you have thousands of dollars worth of insulation because you live in an arctic climate. Congratulations I suppose. Now instead of just spending hundreds of billions on building a new grid Australians will also have to spend hundreds of billions on insulating their houses.
- troupo 3y ago
  To be completely honest, they probably should, and people don't talk enough about proper insulation regardless of the region. E.g. in colder climates many modern buildings are just hermetically sealed boxes with issues around CO2 levels etc.
- bryanlarsen 3y ago
  For a 14C differential you don't need insulation, you just need to seal leaks.
  - throw0101b 3y ago
    > For a 14C differential you don't need insulation, you just need to seal leaks. And hope that your inside air temperature is not at the dew point of the hot, humid air that is outside (thus causing condensation).
    - adrianN 3y ago
      If your house had problems with condensation forming on the outside then I hope it never rains where you are.
      - throw0101b 3y ago
        Water in liquid form (e.g., rain) will (mostly!) go down with gravity, and so overhangs will help a lot, as will proper grade sloping away from your foundations. Water in vapour form will be more diffuse and be everywhere the air is. Further, your cladding / water control layer (which deals with rain (and UV)) generally needs to be open to air so that it can dry properly: * https://en.wikipedia.org/wiki/Rainscreen https://en.wikipedia.org/wiki/Rainscreen so that can lead to moist air getting places that water may not, and if you don't have insulation between the warm-moist outside and the cool-dry inside: * https://buildingscience.com/documents/insights/bsi-001-the-perfect-wall https://buildingscience.com/documents/insights/bsi-001-the-p... problems can start.

hackerlight 3y ago

The picture in my mind was: You have overbuilt solar charging nearby batteries (lithium ion, sodium ion, whatever) to cover the 4-hour busy period at night, and smaller amounts of longer duration storage like pumped hydro to cover the quieter periods after 10pm. I'm not sure if that'd work out to be cheaper than doing the proposed 60% wind/45% solar mix with inter-state transmission. It would reduce the need for new transmission lines, though.

Retric 3y ago

Aka, really sunny just as suggested. Cooling at night requires batteries, but their cost is offset by how cheap they are to charge with excess solar resulting in positive feedback loops. Further, AC needs to work far less hard at night as you avoid solar gain through windows etc, fewer devices are on reducing heat gain, outside temperature drop further reducing heat gain while also increasing AC efficiency.