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Hydro currently produces ~7% of US electricity. Things like pumped hydro and conservation are just a smaller nice to have part of the picture, they're not the s

by erentz 5y ago

Hydro currently produces ~7% of US electricity. Things like pumped hydro and conservation are just a smaller nice to have part of the picture, they're not the solution. CA uses ~15GW of gas power when the sun turns off at 6pm. It still uses 8-10GW of gas during the day when the sun is shining. That gas is going to increase another 2GW when Diablo canyon is switched off. During the day while solar is running it additionally imports 4-6GW from the NW and SW interchanges. When the sun turns off at 6pm it jumps up to 8GW sometimes more of imported electricity. Meanwhile during the afternoon and evening the NW region is generating 20GW with fossil gas and coal power. While only managing to generate 16GW at these same peaks with its hydro power. There is not enough hydro to do this, and you can't build more. CA is a power hungry state that has outsourced much of its pollution to other states. This is a result of targeting renewables rather than targeting clean power. It needs to build firm clean power, whatever form that takes. Targets should be for CO2 emissions. Not for some favored technology.

Retric 5y ago
You misunderstood, the day to day solution is batteries. Hydropower is for when your not getting enough sunlight in the day not when the sun goes down at night. Currently, 5% of all solar power generated in California is wasted and that number keeps increasing because people just keep adding more solar. Storage is currently cost effective, and it’s only getting cheaper. More storage means building even more solar is again cost effective until eventually the grid ends up looking very different.
- erentz 5y ago
  Not following how this would work. So overnight demand of the NW and CAL looks to be ~60GW. Assuming you can get 20GW of hydro between the two (which is a bit above current peaks) as your supplement. So you'd need enough solar to on the cloudiest of days to both keep things running with daytime demand in NW and CAL while still providing enough excess to (picking some numbers) charge up ~30% of the batteries, while the hydro runs to supplement charging the other ~30% of charge, so that overnight the 60% of charge can be drained in conjunction with the 20GW of hydro continuing to run. Why even rely on hydro if solar can still do all this, just build even more solar. Seems shaky and fragile. And this is before you even get to solving the rest of North America.
  - Retric 5y ago
    You need to expand the maximum capacity of hydroelectric generation not the average capacity which means zero new dams. As a sanity check if hydro can average 7% of US electricity 100% of the time that’s equivalent to 70% of US electricity 10% of the time. To greatly simplify if daytime demand is 200GW and nighttime demand is 100GW. You build enough solar to in theory provide 600GW in optimal conditions and 60GW in the worst case accepting most of that is wasted. Still 90% of the time they provide 300+GW in the day which can charge batteries to provide 100GW at night. Which means 90% of days hydro is producing ~0 electricity. The other 10% of the time solar is producing between 300GW and 60GW in the day. If it’s 299GW then hydro needs to supplement 1GW at night. If it’s only 60GW then hydro needs to supplement 140GW in the day and 100GW that night. Now in the real world things aren’t that simple. Hydro isn’t a light switch, and wind is part of the equation etc, but as a first order approximation it works especially as you can use hydro to charge the same batteries that solar or wind would.
    - erentz 5y ago
      You say expand to 70% for 10% of the time. You mean you want to multiply several times over the number of generator halls, penstocks, turbines, generators, and water outflow from existing hydro schemes? There isn't the space for all that. And the cost would be astronomical. Plus the environmental impact of having several times the outflow from most dams at full power would be incredible. You could maybe at a stretch 1.5x it across the US on average. But most plans to expand hydro scheme output around the developed world get met with incredible resistance.
      - Retric 5y ago
        Increasing peak flow from dams is actually great for the environment as flooding is part of the natural ecosystem, this actually doesn’t go far enough to simulate natural variability. Also, dams don’t operate anywhere close to 100% 24/7, what I am describing is generally closer to a 2x increase in maximum generating capacity than 10x which isn’t free but the value of electricity produced would be vastly high more than making up for these costs. I don’t get objections like this: There isn't the space for all that. That’s not an inherent limitation, people built these dams in the first place, we can remove them and build a new structure if that’s what it takes. Don’t flood properties downstream is a perfectly reasonable limitation, don’t build any new infrastructure isn’t. 2019 we produced 100x as much solar power as in 2009, change happens.

by erentz 5y ago

Retric 5y ago

You misunderstood, the day to day solution is batteries. Hydropower is for when your not getting enough sunlight in the day not when the sun goes down at night. Currently, 5% of all solar power generated in California is wasted and that number keeps increasing because people just keep adding more solar. Storage is currently cost effective, and it’s only getting cheaper. More storage means building even more solar is again cost effective until eventually the grid ends up looking very different.

erentz 5y ago
Not following how this would work. So overnight demand of the NW and CAL looks to be ~60GW. Assuming you can get 20GW of hydro between the two (which is a bit above current peaks) as your supplement. So you'd need enough solar to on the cloudiest of days to both keep things running with daytime demand in NW and CAL while still providing enough excess to (picking some numbers) charge up ~30% of the batteries, while the hydro runs to supplement charging the other ~30% of charge, so that overnight the 60% of charge can be drained in conjunction with the 20GW of hydro continuing to run. Why even rely on hydro if solar can still do all this, just build even more solar. Seems shaky and fragile. And this is before you even get to solving the rest of North America.
- Retric 5y ago
  You need to expand the maximum capacity of hydroelectric generation not the average capacity which means zero new dams. As a sanity check if hydro can average 7% of US electricity 100% of the time that’s equivalent to 70% of US electricity 10% of the time. To greatly simplify if daytime demand is 200GW and nighttime demand is 100GW. You build enough solar to in theory provide 600GW in optimal conditions and 60GW in the worst case accepting most of that is wasted. Still 90% of the time they provide 300+GW in the day which can charge batteries to provide 100GW at night. Which means 90% of days hydro is producing ~0 electricity. The other 10% of the time solar is producing between 300GW and 60GW in the day. If it’s 299GW then hydro needs to supplement 1GW at night. If it’s only 60GW then hydro needs to supplement 140GW in the day and 100GW that night. Now in the real world things aren’t that simple. Hydro isn’t a light switch, and wind is part of the equation etc, but as a first order approximation it works especially as you can use hydro to charge the same batteries that solar or wind would.
  - erentz 5y ago
    You say expand to 70% for 10% of the time. You mean you want to multiply several times over the number of generator halls, penstocks, turbines, generators, and water outflow from existing hydro schemes? There isn't the space for all that. And the cost would be astronomical. Plus the environmental impact of having several times the outflow from most dams at full power would be incredible. You could maybe at a stretch 1.5x it across the US on average. But most plans to expand hydro scheme output around the developed world get met with incredible resistance.
    - Retric 5y ago
      Increasing peak flow from dams is actually great for the environment as flooding is part of the natural ecosystem, this actually doesn’t go far enough to simulate natural variability. Also, dams don’t operate anywhere close to 100% 24/7, what I am describing is generally closer to a 2x increase in maximum generating capacity than 10x which isn’t free but the value of electricity produced would be vastly high more than making up for these costs. I don’t get objections like this: There isn't the space for all that. That’s not an inherent limitation, people built these dams in the first place, we can remove them and build a new structure if that’s what it takes. Don’t flood properties downstream is a perfectly reasonable limitation, don’t build any new infrastructure isn’t. 2019 we produced 100x as much solar power as in 2009, change happens.