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I never see intermittency addressed sufficiently. Early this year, I noted the US was almost entirely covered with clouds for a week. Will these renewables real

I never see intermittency addressed sufficiently. Early this year, I noted the US was almost entirely covered with clouds for a week. Will these renewables really have enough battery (or other) storage capacity for prolonged solar/wind insufficiency? There's a lot of "well, with enough batteries or smart grids..." but not enough even back-of-napkin calculations for what such cases would require, likely cost, and consequences of outlier environmental happenings. It's easy/cheap to pile up coal, or fill giant buckets with oil, but batteries are expensive .

Havoc 8y ago
>I never see intermittency addressed sufficiently. Even with storage the cost is falling fast & will approach coal shortly
m_fayer 8y ago
You can have a few coal or gas plants on standby for those rate occasions when reserves are insufficient.
- ctdonath 8y ago
  Problem is you need enough "on standby" to run full-output indefinitely ... at a cost high enough that you may as well just use them instead of unreliable renewables. Don't get me wrong, I'm all for renewables. Run my office near 100% on solar in summer, and run my home partly on year-round. My experience convinces me that while it's nice/fun/clean/etc, it's also painfully unreliable. People talking about renewables while living on coal/etc energy don't seem to grasp this.
  - peterashford 8y ago
    I don't get your argument. In NZ, were very largely running on renewables. Hydro filling in the rest. There's a coal plant in Huntly which can be fired up to fill in any gaps. Most of the time it's not needed and this isn't a big deal.
  - cesarb 8y ago
    > Problem is you need enough "on standby" to run full-output indefinitely ... at a cost high enough that you may as well just use them instead of unreliable renewables. There are two components to the cost of a generator: fixed costs and variable costs, the later being mostly fuel. Even if you have enough standby generators and could run them all the time, if the "unreliable renewables" allow you to reduce their power (using less fuel) or even power some of them down completely, it can be a huge cost advantage. It's even better if you add a bit of storage to the mix: since most generators can't power up instantly, with enough storage they could all be completely powered off instead of idling, saving even more fuel and wear.
  - torpfactory 8y ago
    If you look at any one solar setup's output, yes it varies wildly every time a cloud goes by. If you're off-grid and responsible for your own power, this is a huge problem. You would need a fairly large solar array and some also fairly large batteries to keep you supplied with power. With a large, geographically distributed grid of different types of generation (Wind, Solar, Hydro, Nuclear, maybe a bit of fossil generation, and battery storage to sop up the excess), these problems become much more manageable.
1123581321 8y ago
Where are you looking for these discussions and calculations of capacity and reserve power?
- ctdonath 8y ago
  In every popular discussion advocating "renewable energy". Let's give it a spin. Given a solar operation that can produce 1MW continuous (under normal best conditions, including buffering for night, angles, etc), what happens when it's seriously cloudy for a week? we need to continue that 1MW output for 7 days. That requires 168 MW/h of storage. That would require 800 Tesla PowerPacks, totaling $116,080,000. $116M just to make sure a 1MW provider (which really isn't much) can run a week with insufficient light (hey, sometimes it rains for a while). Then, if the storm continues another day, all the power goes out. To keep electricity on for just one more hour would require another 5 PowerPacks @ $725,500. What people don't seem to grasp about solar/wind + batteries is: when the battery is drained, you're done. No more electricity until the sun pops out again or the wind picks up enough, and no more buffer until those energy "buckets" can be refilled. At this point, optimistic advocates will jump up with "but smart grids!" Yeah, well, show me the numbers. Convince me the national cloud cover I saw a few weeks back (lasting a week) won't promptly shut down the "100% renewables" providers in short order, leaving (say) Chicago completely incapable to achieve the needed 100 degree differential between outdoors and in (that was a very cold week). The value of coal, nuclear, etc is that production keeps going regardless of weather. Renewable energy is absolutely subject to weather, and when the batteries run out, the lights go off.
  - 1123581321 8y ago
    I like that you are running these numbers. However, solar and wind will be overprovisioned when costs are low enough, so they will not run at capacity when the weather is sunny and breezy. Also, they do not provide zero output when it is cloudy or calm. Output should not drop from 100% to 0% in this example. The residential battery cost is significant, but should be broken out by home. A home generator would be more appropriate for several days of emergency power, just as now. These cost about $3,000. Anyone willing to buy a Tesla power pack should not find this cost objectionable. Also, I would not look at popular discussions such as the one we’re having as representative of government and private sector ability to plan renewable energy capacity.
torpfactory 8y ago
I don't think this article does quite enough to address all the concerns but it is pretty deeply researched and outlines a path to 100% renewables by 2050. It's also from 2015 and LiIon battery costs have fallen by 50% since this article was published. http://web.stanford.edu/group/efmh/jacobson/Articles/I/USStatesWWS.pdf http://web.stanford.edu/group/efmh/jacobson/Articles/I/USSta...

Havoc 8y ago

>I never see intermittency addressed sufficiently. Even with storage the cost is falling fast & will approach coal shortly

m_fayer 8y ago

You can have a few coal or gas plants on standby for those rate occasions when reserves are insufficient.

ctdonath 8y ago
Problem is you need enough "on standby" to run full-output indefinitely ... at a cost high enough that you may as well just use them instead of unreliable renewables. Don't get me wrong, I'm all for renewables. Run my office near 100% on solar in summer, and run my home partly on year-round. My experience convinces me that while it's nice/fun/clean/etc, it's also painfully unreliable. People talking about renewables while living on coal/etc energy don't seem to grasp this.
- peterashford 8y ago
  I don't get your argument. In NZ, were very largely running on renewables. Hydro filling in the rest. There's a coal plant in Huntly which can be fired up to fill in any gaps. Most of the time it's not needed and this isn't a big deal.
- cesarb 8y ago
  > Problem is you need enough "on standby" to run full-output indefinitely ... at a cost high enough that you may as well just use them instead of unreliable renewables. There are two components to the cost of a generator: fixed costs and variable costs, the later being mostly fuel. Even if you have enough standby generators and could run them all the time, if the "unreliable renewables" allow you to reduce their power (using less fuel) or even power some of them down completely, it can be a huge cost advantage. It's even better if you add a bit of storage to the mix: since most generators can't power up instantly, with enough storage they could all be completely powered off instead of idling, saving even more fuel and wear.
- torpfactory 8y ago
  If you look at any one solar setup's output, yes it varies wildly every time a cloud goes by. If you're off-grid and responsible for your own power, this is a huge problem. You would need a fairly large solar array and some also fairly large batteries to keep you supplied with power. With a large, geographically distributed grid of different types of generation (Wind, Solar, Hydro, Nuclear, maybe a bit of fossil generation, and battery storage to sop up the excess), these problems become much more manageable.

1123581321 8y ago

Where are you looking for these discussions and calculations of capacity and reserve power?

ctdonath 8y ago
In every popular discussion advocating "renewable energy". Let's give it a spin. Given a solar operation that can produce 1MW continuous (under normal best conditions, including buffering for night, angles, etc), what happens when it's seriously cloudy for a week? we need to continue that 1MW output for 7 days. That requires 168 MW/h of storage. That would require 800 Tesla PowerPacks, totaling $116,080,000. $116M just to make sure a 1MW provider (which really isn't much) can run a week with insufficient light (hey, sometimes it rains for a while). Then, if the storm continues another day, all the power goes out. To keep electricity on for just one more hour would require another 5 PowerPacks @ $725,500. What people don't seem to grasp about solar/wind + batteries is: when the battery is drained, you're done. No more electricity until the sun pops out again or the wind picks up enough, and no more buffer until those energy "buckets" can be refilled. At this point, optimistic advocates will jump up with "but smart grids!" Yeah, well, show me the numbers. Convince me the national cloud cover I saw a few weeks back (lasting a week) won't promptly shut down the "100% renewables" providers in short order, leaving (say) Chicago completely incapable to achieve the needed 100 degree differential between outdoors and in (that was a very cold week). The value of coal, nuclear, etc is that production keeps going regardless of weather. Renewable energy is absolutely subject to weather, and when the batteries run out, the lights go off.
- 1123581321 8y ago
  I like that you are running these numbers. However, solar and wind will be overprovisioned when costs are low enough, so they will not run at capacity when the weather is sunny and breezy. Also, they do not provide zero output when it is cloudy or calm. Output should not drop from 100% to 0% in this example. The residential battery cost is significant, but should be broken out by home. A home generator would be more appropriate for several days of emergency power, just as now. These cost about $3,000. Anyone willing to buy a Tesla power pack should not find this cost objectionable. Also, I would not look at popular discussions such as the one we’re having as representative of government and private sector ability to plan renewable energy capacity.

torpfactory 8y ago

I don't think this article does quite enough to address all the concerns but it is pretty deeply researched and outlines a path to 100% renewables by 2050. It's also from 2015 and LiIon battery costs have fallen by 50% since this article was published. http://web.stanford.edu/group/efmh/jacobson/Articles/I/USStatesWWS.pdf http://web.stanford.edu/group/efmh/jacobson/Articles/I/USSta...