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Power markets are more complicated than most people realize. One thing to note is that solar power can be cheaper than gas, but still not be economic. The fact

Power markets are more complicated than most people realize. One thing to note is that solar power can be cheaper than gas, but still not be economic. The fact of the matter is that an intermittent kWh is not as valuable as an on-demand reliable kWh to a utility who's number 1 priority is reliability. Even as solar is acquired at lower and lower prices, if evening power is generated by expensive and inefficient gas turbines, the customer might not see costs go down (and emissions might not go down either!). Solar is clearly economic in many markets, but we'll never get grid emissions in a place like California down much more without storage.

CapitalistCartr 6y ago
Solar all day, NG all night would be a major improvement over our current system. Especially as batteries get better.
- sephamorr 6y ago
  Depending on where you are, that's pretty close to what's happened. Right now (4pm), the California ISO is generating 73% from renewables+hydro, 7% nuclear, and the balance gas. Naturally, the night replaces solar with gas. This is largely how California has reduced electricity emissions to their current levels.
  - bananabreakfast 6y ago
    And that nuclear power is just from a single plant!
  - Gibbon1 6y ago
    Always gets me that the above is a no brainer. But people married to the argument that we can't have renewables until we solve the storage problem just refuse to even consider it. Disconcerting.
- acidburnNSA 6y ago
  NG is still extraordinarily high carbon. "A little better than coal (if you ignore the pipeline and wellhead losses)" is not something we can settle for given the seriousness of climate change. We need 24/7 low-carbon power. Fracked natural gas for entire nights (recall in winter nights are quite long) is not an option.
Scoundreller 6y ago
Or just smarter appliances. Plenty of opportunities for thermal banking/battery banking. Most of my loads, on average, don't need to run that exact second. I don't mind if my hot water tank super-heats water in the middle of the day for the rest of the day. If electricity is really cheap, my freezer can jump into overdrive. I don't need my clothes to dry in the next hour, just over the next 8. I don't care if my fridge/freezer takes a break while I run the microwave or pre-heat the oven. I don't care if my car charges ASAP as soon as I park, as long as it's charged by 8AM. And let it run as a grid-power bank for a fee. Then you could have A/C systems that make ice or compress refrigerant in a tank.
- dumbfoundded 6y ago
  I think the point is that in any case, price isn't a finish line for solar to replace everything. This process will be much longer and require lots of infrastructure changes in multiple places.
- maallooc 6y ago
  >I don't mind if my hot water tank super-heats water in the middle of the day for the rest of the day. Water does not have the capability to store much energy. >If electricity is really cheap, my freezer can jump into overdrive. Your freezer can't if it's not a ammonia refrigerant. You will actually be wasting energy. >I don't care if my fridge/freezer takes a break Your fridge actually does not use electricity constantly. It detects the temperature and run the motor, stops it when it reaches the desired temp. It's already having a break.
  - Scoundreller 6y ago
    It's common here to have 150L+ water tanks. Can take it from 50C to 75C and then let the anti-scald valve temper the output when drawing. OK on the freezer. Could still take the fridge down to 2C. The concept of the fridge taking a break while running other loads is to reduce peak draw current. If everyone did that, it would make the grid more stable.
    - 6y ago
pydry 6y ago
Intermittency and the unsuitability of grid storage batteries to compensate is heavily played up by the carbon industry. The future of low emissions energy production will be largely driven by overproduction and demand shifting, not banks of grid level batteries. This likely won't happen as soon in America, however, the economy is too tied in to fossil fuels and the appetite to upgrade the electric grid by utility companies heavily invested in gas isnt really there.
- ThomPete 6y ago
  then by your own logic it would happen other places, it doesent.
  - deleted 6y ago
    [deleted]
- asdff 6y ago
  It would be nice if you can have your appliances charging per day, and using a built in battery suited to run at night.
- gwright 6y ago
  It is "played up" because that is how the physics/science works right now. Grid-scale storage is required to smooth out grid-scale intermittent generation.
- peterwoerner 6y ago
  But the solution isn't batteries, it stored hydroelectric. Only works where you have mountains though.
  - greglindahl 6y ago
    How is that a solution when it's difficult to build more of it?
    - peterwoerner 6y ago
remmargorp64 6y ago
All they need to do is build mechanical/hydraulic systems for storing solar power during the day and unleashing it at night. For example, use solar power during the day to pump fluid from a lower reservoir into a higher reservoir, and then harness the energy of the water flowing from the higher reservoir into the lower reservoir through turbines. As long as your output energy is always coming from the turbines, and as long as your solar powered pumps running during the day can keep up with double the rate of drainage flow, then you should have a constant loop with a steady supply of power. This type of system could be retrofitted onto virtually any dam, giving you a way to create a closed loop with constant power and without the water loss typical from a dam (other than evaporation). For areas where water is scarce and a dam isn't feasible, there are also other ideas, such as gravitational potential energy systems that use solar powered energy to lift weights on pulleys, which then power a generator as the weights are lowered by gravity. Other ideas: Thermal storage including molten salts which can efficiently store and release very large quantities of heat energy, compressed air energy storage, flywheels, cryogenic systems, etc...
- 7thaccount 6y ago
  Which all costs a lot of money.
  - drpgq 6y ago
    There's nothing more handwavy than electricity storage
- bananabreakfast 6y ago
  You're wildly underestimating how complicated pumped hydro is. For one thing, existing dams absolutely cannot be converted to pumped hydro. Dams do not store water below them. Water flows downstream because a dam is in a river. There is no water to pump uphill. Unless, of course, you also build a second dam very close downstream to create another lower reservoir. This is usually a bad idea, and better to just find better geography that will support a new pumped hydro dam.
  - 6y ago
blake1 6y ago
As mentioned in the article, solar power is insanely cheap. So while you are right that a kWh of solar is not, on average, as valuable as a kWh of semidispatchable coal, the insane cheapness means that at some point, it is economical to massively overbuild renewable and decommission fossil fuel plants. You provide no evidence for the implausible claim that solar causes emissions to go up: your argument is only that the emissions reducing effect is muted, which may be true. Also, while storage would be helpful, it is not the only way to enable a renewable transition. Additional transmission is enormously helpful: as the sun goes down on California, the wind is picking up in the Midwest. And don’t forget demand response: if smart thermostats received price signals (maybe we should precool this house...) that would alleviate the evening ramp-up issue. So I claim we’ll need less storage than “a whole day’s usage”. But the learning curve applies to batteries as well! This storage won’t cost as much anyway. The whole issue of intermittency is overrated. While a single solar panel might generate intermittently, the solar fleet across a whole state generates more predictably. I am predicting that grid emissions will come down a lot over the coming decades. Partially I’m predicting the past: they’ve already come down, a lot!
- gwright 6y ago
  It doesn't matter that if solar/wind is cheap (or even zero) because you still have to have an alternate power source for when your intermittent power has gone AWOL. You need cheap grid-scale storage, which doesn't exist at the moment.
  - acidburnNSA 6y ago
    Or some other dispatchable low-carbon energy source, which also doesn't really exist at the moment. Load-following nuclear reactors (hooked to thermal storage) could do this physically but a lot has to happen to get the cost down. Meanwhile, various CCS options could play a role if there's a solution for safely storing vast quantities of carbon out of the atmosphere.
  - lukifer 6y ago
    I don't know about its efficacy, but my favorite means of mass energy storage is a gravity battery: literally stacking heavy blocks in a huge tower, which are raised and lowered based on energy demands by automated cranes. https://en.wikipedia.org/wiki/Energy_Vault https://en.wikipedia.org/wiki/Energy_Vault
clairity 6y ago
> "Solar is clearly economic in many markets, but we'll never get grid emissions in a place like California down much more without storage." even before reliable utility-scale storage, there is a lot of low hanging fruit from covering the southwest US in solar and wind. but yes, the costs of intermittent power like wind and solar doesn't by itself end with installation.
GhostVII 6y ago
I wish more places had hourly pricing of power, with good integrations. Would be really cool to be able to set up your appliances/AC/electric car to consume more power when it is cheap. And then you could get battery banks for your house to store power when it is cheap and use it when it is expensive, absorbing the peaks in a decentralized way.
agumonkey 6y ago
It's impressive how systemic predictability matters. When nothing happens at the right time, you basically die.
greglindahl 6y ago
> The fact of the matter is that an intermittent kWh is not as valuable as an on-demand reliable kWh Don't worry -- every single time renewables are mentioned on HN, this aspect is at the top of the posting.
- hrishirc 6y ago
  And as long as it's true, may it long keep getting mentioned.
- tonyedgecombe 6y ago
  Every HN post has something negative at the top.
m463 6y ago
also, solar might not be solar. "Utility scale solar" is ambiguous and can mean solar thermal or pv solar. I think solar thermal might be a completely different animal that is not long-lived and not clean. It might be a similar situation to where "renewable power" turns out to me mostly burning garbage or burning trees. This documentary might be a little biased but also have some interesting insights: https://youtu.be/Zk11vI-7czE https://youtu.be/Zk11vI-7czE
- pfdietz 6y ago
  Concentrated solar thermal is basically dead. PV just slaughtered it.
sunstone 6y ago
These days most contracts are being bid solar+battery at a ratio of about 5:1, if memory serves.
EarthMephit 6y ago
Battery prices are also dropping, although as not as fast as solar, but its at the point where in some regions solar + battery is cheaper than coal Modern Gas turbines can also act as a good backup for solar in times where there is unusual demand because they can start up on under a minute
anotheryou 6y ago
Does cheaper prices open up some less efficient ways of storage? I'm still hoping for this one, just because it's so epic: the giant rock-piston gravity storage: https://www.heindl-energy.com/ https://www.heindl-energy.com/

CapitalistCartr 6y ago

Solar all day, NG all night would be a major improvement over our current system. Especially as batteries get better.

sephamorr 6y ago
Depending on where you are, that's pretty close to what's happened. Right now (4pm), the California ISO is generating 73% from renewables+hydro, 7% nuclear, and the balance gas. Naturally, the night replaces solar with gas. This is largely how California has reduced electricity emissions to their current levels.
- bananabreakfast 6y ago
  And that nuclear power is just from a single plant!
- Gibbon1 6y ago
  Always gets me that the above is a no brainer. But people married to the argument that we can't have renewables until we solve the storage problem just refuse to even consider it. Disconcerting.
acidburnNSA 6y ago
NG is still extraordinarily high carbon. "A little better than coal (if you ignore the pipeline and wellhead losses)" is not something we can settle for given the seriousness of climate change. We need 24/7 low-carbon power. Fracked natural gas for entire nights (recall in winter nights are quite long) is not an option.

Scoundreller 6y ago

Or just smarter appliances. Plenty of opportunities for thermal banking/battery banking. Most of my loads, on average, don't need to run that exact second. I don't mind if my hot water tank super-heats water in the middle of the day for the rest of the day. If electricity is really cheap, my freezer can jump into overdrive. I don't need my clothes to dry in the next hour, just over the next 8. I don't care if my fridge/freezer takes a break while I run the microwave or pre-heat the oven. I don't care if my car charges ASAP as soon as I park, as long as it's charged by 8AM. And let it run as a grid-power bank for a fee. Then you could have A/C systems that make ice or compress refrigerant in a tank.

dumbfoundded 6y ago
I think the point is that in any case, price isn't a finish line for solar to replace everything. This process will be much longer and require lots of infrastructure changes in multiple places.
maallooc 6y ago
>I don't mind if my hot water tank super-heats water in the middle of the day for the rest of the day. Water does not have the capability to store much energy. >If electricity is really cheap, my freezer can jump into overdrive. Your freezer can't if it's not a ammonia refrigerant. You will actually be wasting energy. >I don't care if my fridge/freezer takes a break Your fridge actually does not use electricity constantly. It detects the temperature and run the motor, stops it when it reaches the desired temp. It's already having a break.
- Scoundreller 6y ago
  It's common here to have 150L+ water tanks. Can take it from 50C to 75C and then let the anti-scald valve temper the output when drawing. OK on the freezer. Could still take the fridge down to 2C. The concept of the fridge taking a break while running other loads is to reduce peak draw current. If everyone did that, it would make the grid more stable.
  - 6y ago

pydry 6y ago

Intermittency and the unsuitability of grid storage batteries to compensate is heavily played up by the carbon industry. The future of low emissions energy production will be largely driven by overproduction and demand shifting, not banks of grid level batteries. This likely won't happen as soon in America, however, the economy is too tied in to fossil fuels and the appetite to upgrade the electric grid by utility companies heavily invested in gas isnt really there.

ThomPete 6y ago
then by your own logic it would happen other places, it doesent.
- deleted 6y ago
  [deleted]
asdff 6y ago
It would be nice if you can have your appliances charging per day, and using a built in battery suited to run at night.
gwright 6y ago
It is "played up" because that is how the physics/science works right now. Grid-scale storage is required to smooth out grid-scale intermittent generation.
peterwoerner 6y ago
But the solution isn't batteries, it stored hydroelectric. Only works where you have mountains though.
- greglindahl 6y ago
  How is that a solution when it's difficult to build more of it?
  - peterwoerner 6y ago

remmargorp64 6y ago

All they need to do is build mechanical/hydraulic systems for storing solar power during the day and unleashing it at night. For example, use solar power during the day to pump fluid from a lower reservoir into a higher reservoir, and then harness the energy of the water flowing from the higher reservoir into the lower reservoir through turbines. As long as your output energy is always coming from the turbines, and as long as your solar powered pumps running during the day can keep up with double the rate of drainage flow, then you should have a constant loop with a steady supply of power. This type of system could be retrofitted onto virtually any dam, giving you a way to create a closed loop with constant power and without the water loss typical from a dam (other than evaporation). For areas where water is scarce and a dam isn't feasible, there are also other ideas, such as gravitational potential energy systems that use solar powered energy to lift weights on pulleys, which then power a generator as the weights are lowered by gravity. Other ideas: Thermal storage including molten salts which can efficiently store and release very large quantities of heat energy, compressed air energy storage, flywheels, cryogenic systems, etc...

7thaccount 6y ago
Which all costs a lot of money.
- drpgq 6y ago
  There's nothing more handwavy than electricity storage
bananabreakfast 6y ago
You're wildly underestimating how complicated pumped hydro is. For one thing, existing dams absolutely cannot be converted to pumped hydro. Dams do not store water below them. Water flows downstream because a dam is in a river. There is no water to pump uphill. Unless, of course, you also build a second dam very close downstream to create another lower reservoir. This is usually a bad idea, and better to just find better geography that will support a new pumped hydro dam.
- 6y ago

blake1 6y ago

As mentioned in the article, solar power is insanely cheap. So while you are right that a kWh of solar is not, on average, as valuable as a kWh of semidispatchable coal, the insane cheapness means that at some point, it is economical to massively overbuild renewable and decommission fossil fuel plants. You provide no evidence for the implausible claim that solar causes emissions to go up: your argument is only that the emissions reducing effect is muted, which may be true. Also, while storage would be helpful, it is not the only way to enable a renewable transition. Additional transmission is enormously helpful: as the sun goes down on California, the wind is picking up in the Midwest. And don’t forget demand response: if smart thermostats received price signals (maybe we should precool this house...) that would alleviate the evening ramp-up issue. So I claim we’ll need less storage than “a whole day’s usage”. But the learning curve applies to batteries as well! This storage won’t cost as much anyway. The whole issue of intermittency is overrated. While a single solar panel might generate intermittently, the solar fleet across a whole state generates more predictably. I am predicting that grid emissions will come down a lot over the coming decades. Partially I’m predicting the past: they’ve already come down, a lot!

gwright 6y ago
It doesn't matter that if solar/wind is cheap (or even zero) because you still have to have an alternate power source for when your intermittent power has gone AWOL. You need cheap grid-scale storage, which doesn't exist at the moment.
- acidburnNSA 6y ago
  Or some other dispatchable low-carbon energy source, which also doesn't really exist at the moment. Load-following nuclear reactors (hooked to thermal storage) could do this physically but a lot has to happen to get the cost down. Meanwhile, various CCS options could play a role if there's a solution for safely storing vast quantities of carbon out of the atmosphere.
- lukifer 6y ago
  I don't know about its efficacy, but my favorite means of mass energy storage is a gravity battery: literally stacking heavy blocks in a huge tower, which are raised and lowered based on energy demands by automated cranes. https://en.wikipedia.org/wiki/Energy_Vault https://en.wikipedia.org/wiki/Energy_Vault

clairity 6y ago

> "Solar is clearly economic in many markets, but we'll never get grid emissions in a place like California down much more without storage." even before reliable utility-scale storage, there is a lot of low hanging fruit from covering the southwest US in solar and wind. but yes, the costs of intermittent power like wind and solar doesn't by itself end with installation.

GhostVII 6y ago

I wish more places had hourly pricing of power, with good integrations. Would be really cool to be able to set up your appliances/AC/electric car to consume more power when it is cheap. And then you could get battery banks for your house to store power when it is cheap and use it when it is expensive, absorbing the peaks in a decentralized way.

agumonkey 6y ago

It's impressive how systemic predictability matters. When nothing happens at the right time, you basically die.

greglindahl 6y ago

> The fact of the matter is that an intermittent kWh is not as valuable as an on-demand reliable kWh Don't worry -- every single time renewables are mentioned on HN, this aspect is at the top of the posting.

hrishirc 6y ago
And as long as it's true, may it long keep getting mentioned.
tonyedgecombe 6y ago
Every HN post has something negative at the top.

m463 6y ago

also, solar might not be solar. "Utility scale solar" is ambiguous and can mean solar thermal or pv solar. I think solar thermal might be a completely different animal that is not long-lived and not clean. It might be a similar situation to where "renewable power" turns out to me mostly burning garbage or burning trees. This documentary might be a little biased but also have some interesting insights: https://youtu.be/Zk11vI-7czE https://youtu.be/Zk11vI-7czE

pfdietz 6y ago
Concentrated solar thermal is basically dead. PV just slaughtered it.

sunstone 6y ago

These days most contracts are being bid solar+battery at a ratio of about 5:1, if memory serves.

EarthMephit 6y ago

Battery prices are also dropping, although as not as fast as solar, but its at the point where in some regions solar + battery is cheaper than coal Modern Gas turbines can also act as a good backup for solar in times where there is unusual demand because they can start up on under a minute

anotheryou 6y ago

Does cheaper prices open up some less efficient ways of storage? I'm still hoping for this one, just because it's so epic: the giant rock-piston gravity storage: https://www.heindl-energy.com/ https://www.heindl-energy.com/