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> Would 80% be ideal? I would imagine Solar would start getting iffy over 50%. Depends on how much storage you have. There is very, very little right now so ev

by ac29 5y ago

> Would 80% be ideal? I would imagine Solar would start getting iffy over 50%. Depends on how much storage you have. There is very, very little right now so even 50% might be a stretch. > Maybe I'm being un-imaginative - but is anyone envisioning a global energy grid so we could have solar energy from Australia and Sahara shipped to North America during our night - and back to Asia and Europe from the Southwest during our day?? I'd think you'd need a relatively inexpensive superconducting cable for that to make any sense. Running cables between continents has been a thing for over 150 years, but I'd think resistance losses would make it wildly impractical to power, say, Los Angeles with solar power collected in Australia.

shakna 5y ago
> but I'd think resistance losses would make it wildly impractical to power, say, Los Angeles with solar power collected in Australia. Allow me to present to you the "Australia-Asia Power Link" [0], exporting solar power a distance of about 4,500km, which is still less than half of LA to Australia, but not insignificant. What governs the practicality is often more complex than just power loss. Carbon credits, local taxation, and plain ol' bureaucracy can make it more profitable to export than to consume. [0] https://en.wikipedia.org/wiki/Australia-Asia_Power_Link https://en.wikipedia.org/wiki/Australia-Asia_Power_Link
pydry 5y ago
Grid scale batteries became cost effective within the last year or so, though. It's at the same point solar/wind were a few years ago when they were the cheapest form of energy but received a lot of criticism for making up a small % of total production. Naturally that changed.
ben_w 5y ago
Resistance losses aren’t a huge problem (standard currently available HVDC can do 3.5% loss per 1000km, or 1-(0.965^20) = 51% loss between opposite points of the planet, which is fine given how cheap PV is). The cost for both is the big thing: even just assuming overnight electricity replacement, 12 hours * 2 TW * $100/kWh = $2.4 trillion; the 8 GW English Channel link cost $1.6/km[0][1], which a naive scaling up to 20 Mm and 2 TW would cost $8 trillion. Then the question is “which lasts longer, and which is harder to refurbish at end of life?”. (Numbers are just a guideline. On the one hand there is less demand at night and there will probably be wind and geothermal in the mix, on the other hand we want something that allows everyone to have an energy use currently only available to rich people and this doesn’t cover anything except mere electricity). I have not been able to find the size of the global energy industry in dollars per year to compare this to, only an un-cited claim of “$5 trillion per year … subsidizing the fossil fuel industries”. That said, at this scale I have to ask about the economics of making an orbital ring, transferring power kinetically in what is essentially a ballistic superconductor[2], and now you can put the PV in space on the ring without having to solve the political aspects of “can I convince everyone else I’ve not sneakily designed my power satellite to be used as a death ray, and can I be sure everyone else’s can’t all be told to collectively focus on one place even if I trust the owners’ intentions?” that usually follows any discussion of space-based solar. [0] https://en.wikipedia.org/wiki/High-voltage_direct_current#Costs https://en.wikipedia.org/wiki/High-voltage_direct_current#Co... [1] I’m ignoring converter stations because over 1 Mm they amortise to negligible [2] i.e. purely classical and without the fun quantum magnetic effects: https://en.wikipedia.org/wiki/Ballistic_conduction https://en.wikipedia.org/wiki/Ballistic_conduction

by ac29 5y ago

shakna 5y ago

> but I'd think resistance losses would make it wildly impractical to power, say, Los Angeles with solar power collected in Australia. Allow me to present to you the "Australia-Asia Power Link" [0], exporting solar power a distance of about 4,500km, which is still less than half of LA to Australia, but not insignificant. What governs the practicality is often more complex than just power loss. Carbon credits, local taxation, and plain ol' bureaucracy can make it more profitable to export than to consume. [0] https://en.wikipedia.org/wiki/Australia-Asia_Power_Link https://en.wikipedia.org/wiki/Australia-Asia_Power_Link

pydry 5y ago

Grid scale batteries became cost effective within the last year or so, though. It's at the same point solar/wind were a few years ago when they were the cheapest form of energy but received a lot of criticism for making up a small % of total production. Naturally that changed.

ben_w 5y ago

Resistance losses aren’t a huge problem (standard currently available HVDC can do 3.5% loss per 1000km, or 1-(0.965^20) = 51% loss between opposite points of the planet, which is fine given how cheap PV is). The cost for both is the big thing: even just assuming overnight electricity replacement, 12 hours * 2 TW * $100/kWh = $2.4 trillion; the 8 GW English Channel link cost $1.6/km[0][1], which a naive scaling up to 20 Mm and 2 TW would cost $8 trillion. Then the question is “which lasts longer, and which is harder to refurbish at end of life?”. (Numbers are just a guideline. On the one hand there is less demand at night and there will probably be wind and geothermal in the mix, on the other hand we want something that allows everyone to have an energy use currently only available to rich people and this doesn’t cover anything except mere electricity). I have not been able to find the size of the global energy industry in dollars per year to compare this to, only an un-cited claim of “$5 trillion per year … subsidizing the fossil fuel industries”. That said, at this scale I have to ask about the economics of making an orbital ring, transferring power kinetically in what is essentially a ballistic superconductor[2], and now you can put the PV in space on the ring without having to solve the political aspects of “can I convince everyone else I’ve not sneakily designed my power satellite to be used as a death ray, and can I be sure everyone else’s can’t all be told to collectively focus on one place even if I trust the owners’ intentions?” that usually follows any discussion of space-based solar. [0] https://en.wikipedia.org/wiki/High-voltage_direct_current#Costs https://en.wikipedia.org/wiki/High-voltage_direct_current#Co... [1] I’m ignoring converter stations because over 1 Mm they amortise to negligible [2] i.e. purely classical and without the fun quantum magnetic effects: https://en.wikipedia.org/wiki/Ballistic_conduction https://en.wikipedia.org/wiki/Ballistic_conduction