7 ms·

One very important thing missing is that solar is not dispatchable. It does not serve the same purpose as coal and it is an apples to oranges comparison between

One very important thing missing is that solar is not dispatchable. It does not serve the same purpose as coal and it is an apples to oranges comparison between solar and coal. Coal provides baseless power--coal plants are designed to run at a relatively steady level for more than 90% of the time. Reliable power is critical for things like server farms which draw power all the time. Solar cannot serve the same purpose without battery or other backup. At this time of year in places like California, solar doesn't help meet peak demand either. http://content.caiso.com/green/renewrpt/20160503_DailyRenewablesWatch.pdf http://content.caiso.com/green/renewrpt/20160503_DailyRenewa... Solar has a role, but comparing it to coal is misleading.

jenno 10y ago
A lot of people use the battery argument when it comes to solar, but isn't Musk's home battery pack designed specifically for this purpose?
- barney54 10y ago
  No. They discontinued the larger battery and it isn't designed to operate at grid scale. http://gizmodo.com/tesla-is-discontinuing-its-10-kilowatt-powerwall-1767250649 http://gizmodo.com/tesla-is-discontinuing-its-10-kilowatt-po...
  - Brakenshire 10y ago
    FWIW, your article says that the remaining Powerwall is designed exactly for this purpose. > The larger Powerwall was positioned as a longer-term back up power supply, which GTM noted was looking like a hard sell, with other market alternatives that were priced far below the $3500 price tag. > The remaining 6.4 kwh device has less capacity, and is designed more to shift the load of available power, such as from a solar panel, to times when the production of such energy is lower.
  - nxzero 10y ago
    Yes and no. Tesla has decided that it won’t be making the 10kWh stationary storage batteries it unveiled in April 2015, instead focusing exclusively on the 7kWh version. There's nothing stopping anyone from getting more than one battery to make up for the capacity that was offered by the larger model.
  - chrisatumd 10y ago
    They announced three products initially. Two Powerwall products (7kWh daily cycler and 10kWh emergency backup) and a grid scale product called Powerpack. The product that was canceled was the 10kWh emergency backup. They are still selling the grid scale Powerpack.
  - mtgx 10y ago
    They discontinued the battery with the lower number of charges because the people actually prefer the more expensive one (per KWh) with higher number of charges. Also the Powerwall is for home use. For utilities they offer Powerpacks, and they are already on sale: https://www.teslamotors.com/powerpack/design https://www.teslamotors.com/powerpack/design
- Cthulhu_ 10y ago
  *Tesla's, Musk is only the CEO of the company that designed that device, and attributing Musk with its invention or production isn't flattering for the (faceless?) engineers behind the brand.
  - jonknee 10y ago
    Yes, we should cite the brilliant engineer who came up with the idea of storing electricity in a battery instead of the CEO that enabled low enough production cost of said batteries to make it feasible... There are many things Musk shouldn't be credited with, but this is not one of those things.
- dragontamer 10y ago
  As are CAES, Redox Flow Batteries, Pumped hydro, and other utility-scale energy storage. Energy storage is improving rapidly. Lithium-Ion batteries are but one technology that I don't personally expect will become the norm at grid-scale.
- JoeAltmaier 10y ago
  I thought that was a UPS, designed to cover outages for a short time. Not all night.
projectramo 10y ago
This is absolutely true. But the solar can still be used to nip in the use of fuels. If you have a fast acting source that can follow the solar signal, you'll still make a dent in the consumption of the fuel that creates the energy.
mavhc 10y ago
Also need wind to provide base load of course. It's always windy somewhere.
- harterrt 10y ago
  Transporting electricity is not trivial.
  - epistasis 10y ago
    Actually, it kind of is, the technology (high voltage DC) is well understood and being deployed at high rates in China. It's also affordable. Assuming no new breakthroughs in wind or solar technology, and ignoring storage, we can use HVDC with lots of wind and solar to eliminate 75% of our electricity emissions, and even slightly lower the cost of electricity. And that's even without shifting any use right now: http://arstechnica.com/science/2016/01/making-a-single-us-electrical-system-boosts-renewables-lowers-costs/ http://arstechnica.com/science/2016/01/making-a-single-us-el... http://rameznaam.com/2016/01/31/how-far-can-renewables-go-pretty-darn-far/ http://rameznaam.com/2016/01/31/how-far-can-renewables-go-pr...
ZeroGravitas 10y ago
> "At this time of year in places like California, solar doesn't help meet peak demand". That's a very specific claim, and I don't think your cited graph even supports it. Presumably, you say "this time of year" because you know that the yearly peak in California is driven by air-con usage in the summer afternoons, which correlates very well with solar. But even right now, in early May, the graph is mostly flat through the afternoon and evening, with only the slight peak at 8 or 9 at night making your statement true in a very narrow sense. Notably however, the graph only includes grid side solar production, so panels on homes or business roofs are not included in the graph. If you added those to the total demand curve would shift upwards during solar production hours.
- barney54 10y ago
  The peak demand in California yesterday was at 8:15 pm and solar produced zero electricity at 8:00 pm. http://content.caiso.com/green/renewrpt/20160503_DailyRenewablesWatch.txt http://content.caiso.com/green/renewrpt/20160503_DailyRenewa... But that's that the biggest problem. The problem is that solar is decreasing at demand is increasing. This is the problem they describe with the duck curve. https://www.caiso.com/Documents/FlexibleResourcesHelpRenewables_FastFacts.pdf https://www.caiso.com/Documents/FlexibleResourcesHelpRenewab... Yes, solar can help meet peak load during the summer, but not the rest of the year and it causes stress on the system by requiring a lot of power to spin up to meet demand and solar decreases.
  - Osiris30 10y ago
    And these are some solutions for the duck curve ramp up problem - how you teach he duck to fly: https://www.raponline.org/featured-work/teach-the-duck-to-fly-integrating-renewable-energy https://www.raponline.org/featured-work/teach-the-duck-to-fl...
  - ZeroGravitas 10y ago
    I don't think you understood my comment. You don't know when peak demand in California was yesterday, because you're looking at a graph of the utility company's electricity production, not electricity demand. You'd need to add all the self-consumption by "behind-the-meter" solar installations on homes and businesses to find out the real demand peak. From the perspective of CAISO, solar self-generation is indistiguishable from reduced demand. We know from historical figures that the absolute highest yearly peak in California, the one that you need to build your grid to withstand at great expense even if it only requires that load for a short period of time per year correlates well with solar, and so solar saves lots of money by shaving that peak. The "duck curve" is also not a demand curve, it's demand, minus self-generated-solar, minus grid-generated-solar. And even then, it only appears in the winter months, when demand in California is on the low end of the yearly cycle something like a third of peak demand in the summer months. (Note the graphs showing the duck curve in your second link are from January and March).
maxerickson 10y ago
When you call coal baseload (I assume this is what you intended with baseless), you are contrasting it with dispatchable generation. Coal isn't nearly as responsive as hydro or natural gas or whatnot. The difference between solar and coal is that the output of coal is more reliable.
- barney54 10y ago
  No. According to the US Energy Information Administration, coal is dispatchable. https://www.eia.gov/forecasts/aeo/electricity_generation.cfm https://www.eia.gov/forecasts/aeo/electricity_generation.cfm It is correct that coal does not ramp up or down quickly, but that is not a characteristic of dispatchablilty.
- rhino369 10y ago
  There are varying levels of dispatch-ability. You can ensure coal is on. And you can also turn it off. You just can't do it near instantaneously. It's exists between something like nuclear (which has to just be on for months at a time) and natural gas peaker plants (which turn off and one during the day to meet demand. You could, for example, run coal plants during the winter (when there is little sun) and not during the summer. Or you could run coal on cloudy days. Or just turn it off on weekends.
Osiris30 10y ago
Correct. But in large enough grid there are many non-fossil ways available using existing, deployable tech to integrate a high-penetration of non-dispatchable renewables. For example - utility scale storage (pumped hydro); distributed storage (home batteries and Vehicle-to-grid battery Ev cars); demand-side management; power-to-gas (hydrogen); and geographic grid integration. See more at http://www.nrel.gov/analysis/re_futures/ http://www.nrel.gov/analysis/re_futures/ https://www.raponline.org/featured-work/teach-the-duck-to-fly-integrating-renewable-energy https://www.raponline.org/featured-work/teach-the-duck-to-fl... http://cleantechnica.com/2016/03/02/base-load-power-is-a-myth-used-for-defending-the-fossil-fuel-industry/ http://cleantechnica.com/2016/03/02/base-load-power-is-a-myt... http://cleantechnica.com/2014/08/08/rmi-blows-lid-baseload-power-myth-video/ http://cleantechnica.com/2014/08/08/rmi-blows-lid-baseload-p...
- harterrt 10y ago
  But stored solar energy no longer undercuts coal for most of these storage technologies. Pumped hydro is probably the best bet, but is very geography dependent. Adding transmission is a non-trivial investment.
  - zanny 10y ago
    > Pumped hydro is probably the best bet, but is very geography dependent. You could build surface level reservoirs as two tank hydroelectric dams, and then use the water as an energy reserve as well as freshwater reserve.
  - thatcat 10y ago
    Rail storage is the cheaper, more versatile version of pumped hydro. https://www.greentechmedia.com/articles/read/First-Grid-Scale-Rail-Energy-Storage-Project-Gets-Environmental-Approval-Fr https://www.greentechmedia.com/articles/read/First-Grid-Scal... https://news.ycombinator.com/item?id=11595195 https://news.ycombinator.com/item?id=11595195
    - deelowe 10y ago
      The physics don't make sense for that one. Simple back of the envelope example: How much mass does a train need and/or how far does it need to fall to provide the same kinetic energy as a lake? We have a pumped hydro solution where I live. It's huge and only supplements a small power plant.
zeroxfe 10y ago
> Solar cannot serve the same purpose without battery or other backup. Think of the battery as a really big capacitor operating on a larger time-scale. It's perfectly reasonable to smooth out power this way, and as battery technology improves, you will certainly see more reliable power from solar for things like server farms.
- Cthulhu_ 10y ago
  More reliable, but more costly, too; this solar price comparison is skewed if you don't also include the cost of said batteries / battery capacity. Of course, comparing with coal is also missing the environmental impact.
  - daveguy 10y ago
    Also note that there are cheaper energy storage methods than batteries. Compressed air, pumped water, flywheel and the recently discussed Ares gravity-rail systems have various price points for storage (kWh) and delivery (kW). Here is the ARES discussion: https://news.ycombinator.com/item?id=11595195 https://news.ycombinator.com/item?id=11595195 I agree storage (if required) and environmental impact should both be considered when comparing different energy options.
cinquemb 10y ago
You would think CSP would at least get a mention on these subjects and how well it integrates with present structure of how we allocate of energy and can complement for those who require use of molten salts for dispatchability… its not like we burn coal in our cars to power steam turbine anyways…
riprowan 10y ago
You see a shortcoming of solar, I see a shortcoming of energy storage technology. (I understand your actual point, and agree with it)
blazespin 10y ago
Not when you realize the desalination is a big thing around the world.
svalorzen 10y ago
There's something I never understood though. Technically there's always a side of the Earth that is under the Sun, so why can't countries make some sort of equal-sharing energy agreement to avoid needing batteries, if not at all at least hugely decreas the need for them? So that when it's night on one side of the Earth, everything just runs off the surplus on the other side? Is it just too hard to move electricity so far away?
- brianwawok 10y ago
  So you are saying run a power line across the ocean, so the US can power Europe and Vice Versa? Maintaining fiber optic cables can be hard across the ocean. How about a power line that has a diameter of 50 feet? I can't even imagine the engineering of that. Info on losses here: https://en.wikipedia.org/wiki/Electric_power_transmission#Losses https://en.wikipedia.org/wiki/Electric_power_transmission#Lo... No idea on the math for what % of power we would lose across the ocean. Seems local batteries would win out..
  - fdsaaf 10y ago
    The article says that a 100-mile 765kV transmission line loses 1.5% to 0.5%. Let's be optimistic and assume we can get closer to the latter and deliver 99.5% of original power over 100 miles. NYC-LON is 3,466 miles on the shortest possible path. Let's call it 3,500 miles. Over that distance, we'd deliver 99.5% ^ (3,500 / 100) = 83% of our original power. The circumference of the earth at the equator is 24,901 miles. Halfway around the world, we'd deliver 29% of original power.
  - jfoutz 10y ago
    at that scale, thousands of miles, and enough power to drive a continent, maybe superconducting cables are worth it.
  - harterrt 10y ago
    Local kinetic storage like pumped hydro have an efficiency advantage over batteries (at least with current tech)
- 10y ago
whatever_dude 10y ago
We have never had to deal with the problem of storage for solar power. That's still in its infancy, but as it becomes more mainstream that will change. It's a different game altogether - batteries etc instead of train cars full of coal. But it will happen.
dirichletdelta 10y ago
To give you some illumination on how to deal with intermittent solar checkout out the best paper I've read on this subject: Jacobson, Delucchi on Wind, Water and Solar https://web.stanford.edu/group/efmh/jacobson/Articles/I/JDEnPolicyPt1.pdf https://web.stanford.edu/group/efmh/jacobson/Articles/I/JDEn...
AtlasLion 10y ago
That's why many solar plants use molten salts to store energy and generate electricity even at night. "Technicians say that the Noor 2 and 3 plants, due to open in 2017 will store energy for up to eight hours – opening the prospect of 24/7 solar energy in the Sahara, and the surrounding region." http://www.theguardian.com/environment/2015/oct/26/morocco-poised-to-become-a-solar-superpower-with-launch-of-desert-mega-project http://www.theguardian.com/environment/2015/oct/26/morocco-p...
- Brakenshire 10y ago
  Solar thermal is not really comparable to solar PV. This article, if I'm not mistaken, is talking about PV, which is an entirely separate technology, with unrelated learning curves / cost reductions.
7952 10y ago
Coal is usually designed to run all the time rather than be dispatchable on a minute-by-minute basis. To make it dispatchable you need to run it as "spinning reserve" and increase generation. But it cannot be turned on in a few minutes like a modern gas plant. And for it to be economical coal needs to be turned on all the time. Solar reduces the base load required and makes the maintenance and capital costs of coal stations higher.
jussij 10y ago
> Solar cannot serve the same purpose without battery Elon Musk, CEO of Tesla is some 2 to 5 years away from fixing that battery issue and getting extremely rich in the process.
Shivetya 10y ago
well the US's next Manhattan style project should be a nationwide distribution and storage system. We certainly have the tech and resources to move the majority of the country onto renewable sources within a decade. the only question is, can politicians be convinced to do something good for the country which may not keep them in office?
MaysonL 10y ago
Until you do concentrated solar thermal using molten salts to store heat to drive a generator. See this announcement of one of the world's largest solar plants: http://electrek.co/2016/05/03/worlds-largest-coal-supplier-building-one-of-worlds-largest-solar-power-plants/ http://electrek.co/2016/05/03/worlds-largest-coal-supplier-b...
tedsanders 10y ago
It's misleading to say solar doesn't help meet peak demand in California. For at least the past 20 years in California, the annual peak electricity usage has ALWAYS occurred between 2pm and 5pm: https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory.pdf https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory... It's true that the daily peak is in the evening and that won't be helped by solar. But grid generation capacity is built to handle the annual peak, not the daily peak, so the annual peak is what matters. And because the annual peak tends to be hot afternoons, solar actually will replace other generation in the long run. I used to analyze this stuff professionally when I worked at a California utility.

jenno 10y ago

A lot of people use the battery argument when it comes to solar, but isn't Musk's home battery pack designed specifically for this purpose?

barney54 10y ago
No. They discontinued the larger battery and it isn't designed to operate at grid scale. http://gizmodo.com/tesla-is-discontinuing-its-10-kilowatt-powerwall-1767250649 http://gizmodo.com/tesla-is-discontinuing-its-10-kilowatt-po...
- Brakenshire 10y ago
  FWIW, your article says that the remaining Powerwall is designed exactly for this purpose. > The larger Powerwall was positioned as a longer-term back up power supply, which GTM noted was looking like a hard sell, with other market alternatives that were priced far below the $3500 price tag. > The remaining 6.4 kwh device has less capacity, and is designed more to shift the load of available power, such as from a solar panel, to times when the production of such energy is lower.
- nxzero 10y ago
  Yes and no. Tesla has decided that it won’t be making the 10kWh stationary storage batteries it unveiled in April 2015, instead focusing exclusively on the 7kWh version. There's nothing stopping anyone from getting more than one battery to make up for the capacity that was offered by the larger model.
- chrisatumd 10y ago
  They announced three products initially. Two Powerwall products (7kWh daily cycler and 10kWh emergency backup) and a grid scale product called Powerpack. The product that was canceled was the 10kWh emergency backup. They are still selling the grid scale Powerpack.
- mtgx 10y ago
  They discontinued the battery with the lower number of charges because the people actually prefer the more expensive one (per KWh) with higher number of charges. Also the Powerwall is for home use. For utilities they offer Powerpacks, and they are already on sale: https://www.teslamotors.com/powerpack/design https://www.teslamotors.com/powerpack/design
Cthulhu_ 10y ago
*Tesla's, Musk is only the CEO of the company that designed that device, and attributing Musk with its invention or production isn't flattering for the (faceless?) engineers behind the brand.
- jonknee 10y ago
  Yes, we should cite the brilliant engineer who came up with the idea of storing electricity in a battery instead of the CEO that enabled low enough production cost of said batteries to make it feasible... There are many things Musk shouldn't be credited with, but this is not one of those things.
dragontamer 10y ago
As are CAES, Redox Flow Batteries, Pumped hydro, and other utility-scale energy storage. Energy storage is improving rapidly. Lithium-Ion batteries are but one technology that I don't personally expect will become the norm at grid-scale.
JoeAltmaier 10y ago
I thought that was a UPS, designed to cover outages for a short time. Not all night.

projectramo 10y ago

This is absolutely true. But the solar can still be used to nip in the use of fuels. If you have a fast acting source that can follow the solar signal, you'll still make a dent in the consumption of the fuel that creates the energy.

mavhc 10y ago

Also need wind to provide base load of course. It's always windy somewhere.

harterrt 10y ago
Transporting electricity is not trivial.
- epistasis 10y ago
  Actually, it kind of is, the technology (high voltage DC) is well understood and being deployed at high rates in China. It's also affordable. Assuming no new breakthroughs in wind or solar technology, and ignoring storage, we can use HVDC with lots of wind and solar to eliminate 75% of our electricity emissions, and even slightly lower the cost of electricity. And that's even without shifting any use right now: http://arstechnica.com/science/2016/01/making-a-single-us-electrical-system-boosts-renewables-lowers-costs/ http://arstechnica.com/science/2016/01/making-a-single-us-el... http://rameznaam.com/2016/01/31/how-far-can-renewables-go-pretty-darn-far/ http://rameznaam.com/2016/01/31/how-far-can-renewables-go-pr...

ZeroGravitas 10y ago

> "At this time of year in places like California, solar doesn't help meet peak demand". That's a very specific claim, and I don't think your cited graph even supports it. Presumably, you say "this time of year" because you know that the yearly peak in California is driven by air-con usage in the summer afternoons, which correlates very well with solar. But even right now, in early May, the graph is mostly flat through the afternoon and evening, with only the slight peak at 8 or 9 at night making your statement true in a very narrow sense. Notably however, the graph only includes grid side solar production, so panels on homes or business roofs are not included in the graph. If you added those to the total demand curve would shift upwards during solar production hours.

barney54 10y ago
The peak demand in California yesterday was at 8:15 pm and solar produced zero electricity at 8:00 pm. http://content.caiso.com/green/renewrpt/20160503_DailyRenewablesWatch.txt http://content.caiso.com/green/renewrpt/20160503_DailyRenewa... But that's that the biggest problem. The problem is that solar is decreasing at demand is increasing. This is the problem they describe with the duck curve. https://www.caiso.com/Documents/FlexibleResourcesHelpRenewables_FastFacts.pdf https://www.caiso.com/Documents/FlexibleResourcesHelpRenewab... Yes, solar can help meet peak load during the summer, but not the rest of the year and it causes stress on the system by requiring a lot of power to spin up to meet demand and solar decreases.
- Osiris30 10y ago
  And these are some solutions for the duck curve ramp up problem - how you teach he duck to fly: https://www.raponline.org/featured-work/teach-the-duck-to-fly-integrating-renewable-energy https://www.raponline.org/featured-work/teach-the-duck-to-fl...
- ZeroGravitas 10y ago
  I don't think you understood my comment. You don't know when peak demand in California was yesterday, because you're looking at a graph of the utility company's electricity production, not electricity demand. You'd need to add all the self-consumption by "behind-the-meter" solar installations on homes and businesses to find out the real demand peak. From the perspective of CAISO, solar self-generation is indistiguishable from reduced demand. We know from historical figures that the absolute highest yearly peak in California, the one that you need to build your grid to withstand at great expense even if it only requires that load for a short period of time per year correlates well with solar, and so solar saves lots of money by shaving that peak. The "duck curve" is also not a demand curve, it's demand, minus self-generated-solar, minus grid-generated-solar. And even then, it only appears in the winter months, when demand in California is on the low end of the yearly cycle something like a third of peak demand in the summer months. (Note the graphs showing the duck curve in your second link are from January and March).

maxerickson 10y ago

When you call coal baseload (I assume this is what you intended with baseless), you are contrasting it with dispatchable generation. Coal isn't nearly as responsive as hydro or natural gas or whatnot. The difference between solar and coal is that the output of coal is more reliable.

barney54 10y ago
No. According to the US Energy Information Administration, coal is dispatchable. https://www.eia.gov/forecasts/aeo/electricity_generation.cfm https://www.eia.gov/forecasts/aeo/electricity_generation.cfm It is correct that coal does not ramp up or down quickly, but that is not a characteristic of dispatchablilty.
rhino369 10y ago
There are varying levels of dispatch-ability. You can ensure coal is on. And you can also turn it off. You just can't do it near instantaneously. It's exists between something like nuclear (which has to just be on for months at a time) and natural gas peaker plants (which turn off and one during the day to meet demand. You could, for example, run coal plants during the winter (when there is little sun) and not during the summer. Or you could run coal on cloudy days. Or just turn it off on weekends.

Osiris30 10y ago

Correct. But in large enough grid there are many non-fossil ways available using existing, deployable tech to integrate a high-penetration of non-dispatchable renewables. For example - utility scale storage (pumped hydro); distributed storage (home batteries and Vehicle-to-grid battery Ev cars); demand-side management; power-to-gas (hydrogen); and geographic grid integration. See more at http://www.nrel.gov/analysis/re_futures/ http://www.nrel.gov/analysis/re_futures/ https://www.raponline.org/featured-work/teach-the-duck-to-fly-integrating-renewable-energy https://www.raponline.org/featured-work/teach-the-duck-to-fl... http://cleantechnica.com/2016/03/02/base-load-power-is-a-myth-used-for-defending-the-fossil-fuel-industry/ http://cleantechnica.com/2016/03/02/base-load-power-is-a-myt... http://cleantechnica.com/2014/08/08/rmi-blows-lid-baseload-power-myth-video/ http://cleantechnica.com/2014/08/08/rmi-blows-lid-baseload-p...

harterrt 10y ago
But stored solar energy no longer undercuts coal for most of these storage technologies. Pumped hydro is probably the best bet, but is very geography dependent. Adding transmission is a non-trivial investment.
- zanny 10y ago
  > Pumped hydro is probably the best bet, but is very geography dependent. You could build surface level reservoirs as two tank hydroelectric dams, and then use the water as an energy reserve as well as freshwater reserve.
- thatcat 10y ago
  Rail storage is the cheaper, more versatile version of pumped hydro. https://www.greentechmedia.com/articles/read/First-Grid-Scale-Rail-Energy-Storage-Project-Gets-Environmental-Approval-Fr https://www.greentechmedia.com/articles/read/First-Grid-Scal... https://news.ycombinator.com/item?id=11595195 https://news.ycombinator.com/item?id=11595195
  - deelowe 10y ago
    The physics don't make sense for that one. Simple back of the envelope example: How much mass does a train need and/or how far does it need to fall to provide the same kinetic energy as a lake? We have a pumped hydro solution where I live. It's huge and only supplements a small power plant.

zeroxfe 10y ago

> Solar cannot serve the same purpose without battery or other backup. Think of the battery as a really big capacitor operating on a larger time-scale. It's perfectly reasonable to smooth out power this way, and as battery technology improves, you will certainly see more reliable power from solar for things like server farms.

Cthulhu_ 10y ago
More reliable, but more costly, too; this solar price comparison is skewed if you don't also include the cost of said batteries / battery capacity. Of course, comparing with coal is also missing the environmental impact.
- daveguy 10y ago
  Also note that there are cheaper energy storage methods than batteries. Compressed air, pumped water, flywheel and the recently discussed Ares gravity-rail systems have various price points for storage (kWh) and delivery (kW). Here is the ARES discussion: https://news.ycombinator.com/item?id=11595195 https://news.ycombinator.com/item?id=11595195 I agree storage (if required) and environmental impact should both be considered when comparing different energy options.

cinquemb 10y ago

You would think CSP would at least get a mention on these subjects and how well it integrates with present structure of how we allocate of energy and can complement for those who require use of molten salts for dispatchability… its not like we burn coal in our cars to power steam turbine anyways…

riprowan 10y ago

You see a shortcoming of solar, I see a shortcoming of energy storage technology. (I understand your actual point, and agree with it)

blazespin 10y ago

Not when you realize the desalination is a big thing around the world.

svalorzen 10y ago

There's something I never understood though. Technically there's always a side of the Earth that is under the Sun, so why can't countries make some sort of equal-sharing energy agreement to avoid needing batteries, if not at all at least hugely decreas the need for them? So that when it's night on one side of the Earth, everything just runs off the surplus on the other side? Is it just too hard to move electricity so far away?

brianwawok 10y ago
So you are saying run a power line across the ocean, so the US can power Europe and Vice Versa? Maintaining fiber optic cables can be hard across the ocean. How about a power line that has a diameter of 50 feet? I can't even imagine the engineering of that. Info on losses here: https://en.wikipedia.org/wiki/Electric_power_transmission#Losses https://en.wikipedia.org/wiki/Electric_power_transmission#Lo... No idea on the math for what % of power we would lose across the ocean. Seems local batteries would win out..
- fdsaaf 10y ago
  The article says that a 100-mile 765kV transmission line loses 1.5% to 0.5%. Let's be optimistic and assume we can get closer to the latter and deliver 99.5% of original power over 100 miles. NYC-LON is 3,466 miles on the shortest possible path. Let's call it 3,500 miles. Over that distance, we'd deliver 99.5% ^ (3,500 / 100) = 83% of our original power. The circumference of the earth at the equator is 24,901 miles. Halfway around the world, we'd deliver 29% of original power.
- jfoutz 10y ago
  at that scale, thousands of miles, and enough power to drive a continent, maybe superconducting cables are worth it.
- harterrt 10y ago
  Local kinetic storage like pumped hydro have an efficiency advantage over batteries (at least with current tech)
10y ago

whatever_dude 10y ago

We have never had to deal with the problem of storage for solar power. That's still in its infancy, but as it becomes more mainstream that will change. It's a different game altogether - batteries etc instead of train cars full of coal. But it will happen.

dirichletdelta 10y ago

To give you some illumination on how to deal with intermittent solar checkout out the best paper I've read on this subject: Jacobson, Delucchi on Wind, Water and Solar https://web.stanford.edu/group/efmh/jacobson/Articles/I/JDEnPolicyPt1.pdf https://web.stanford.edu/group/efmh/jacobson/Articles/I/JDEn...

AtlasLion 10y ago

That's why many solar plants use molten salts to store energy and generate electricity even at night. "Technicians say that the Noor 2 and 3 plants, due to open in 2017 will store energy for up to eight hours – opening the prospect of 24/7 solar energy in the Sahara, and the surrounding region." http://www.theguardian.com/environment/2015/oct/26/morocco-poised-to-become-a-solar-superpower-with-launch-of-desert-mega-project http://www.theguardian.com/environment/2015/oct/26/morocco-p...

Brakenshire 10y ago
Solar thermal is not really comparable to solar PV. This article, if I'm not mistaken, is talking about PV, which is an entirely separate technology, with unrelated learning curves / cost reductions.

7952 10y ago

Coal is usually designed to run all the time rather than be dispatchable on a minute-by-minute basis. To make it dispatchable you need to run it as "spinning reserve" and increase generation. But it cannot be turned on in a few minutes like a modern gas plant. And for it to be economical coal needs to be turned on all the time. Solar reduces the base load required and makes the maintenance and capital costs of coal stations higher.

jussij 10y ago

> Solar cannot serve the same purpose without battery Elon Musk, CEO of Tesla is some 2 to 5 years away from fixing that battery issue and getting extremely rich in the process.

Shivetya 10y ago

well the US's next Manhattan style project should be a nationwide distribution and storage system. We certainly have the tech and resources to move the majority of the country onto renewable sources within a decade. the only question is, can politicians be convinced to do something good for the country which may not keep them in office?

MaysonL 10y ago

Until you do concentrated solar thermal using molten salts to store heat to drive a generator. See this announcement of one of the world's largest solar plants: http://electrek.co/2016/05/03/worlds-largest-coal-supplier-building-one-of-worlds-largest-solar-power-plants/ http://electrek.co/2016/05/03/worlds-largest-coal-supplier-b...

tedsanders 10y ago

It's misleading to say solar doesn't help meet peak demand in California. For at least the past 20 years in California, the annual peak electricity usage has ALWAYS occurred between 2pm and 5pm: https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory.pdf https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory... It's true that the daily peak is in the evening and that won't be helped by solar. But grid generation capacity is built to handle the annual peak, not the daily peak, so the annual peak is what matters. And because the annual peak tends to be hot afternoons, solar actually will replace other generation in the long run. I used to analyze this stuff professionally when I worked at a California utility.