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Saying that solar is less expensive than nat gas is misleading. It's and apples to oranges comparison. To make a valid comparison you need to compare solar + ba

Saying that solar is less expensive than nat gas is misleading. It's and apples to oranges comparison. To make a valid comparison you need to compare solar + batteries to natural gas. There is value to electricity production that has an on/off switch because it helps keep the grid stable.

DesiLurker 10y ago
with grid tie-in your grid is the battery.
philipkglass 10y ago
At modest levels of penetration it doesn't matter much that solar is non-dispatchable. There's already enough spare capacity in the system that you don't need to build backup specifically for solar. Consider, for example, the tens-of-gigawatts CAISO demand gap between 3:00 AM in April and 6:00 PM on the hottest day of August. The system already had to be ready for the peak-demand situation. Adding solar to the grid doesn't require new dispatchable backup capacity until penetration rises significantly. The backup capacity that was there before solar is a sunk cost. You might as well say that calling nat gas cheaper than solar is misleading because a valid comparison would require carbon capture and storage on the fossil plants.
- barney54 10y ago
  Solar did not help meet peak demand today in California: http://www.caiso.com/Pages/TodaysOutlook.aspx http://www.caiso.com/Pages/TodaysOutlook.aspx Nor does solar help meet peak demand for 2/3rds of the year because peak demand comes after the sun goes down. Solar can help during some summer days, but for much of the year it makes the system less efficient by requiring more ramping up and down of other generation resources.
  - teach 10y ago
    Once we get our Tesla Powerwall batteries, that should help with peak demand, no?
    - Symmetry 10y ago
      Only if they sell power back onto the grid when there's more demand than can be met. Which is a doable thing but we don't have the framework quite in place yet.
      - philipkglass 10y ago
        Localized storage on households and businesses can help even if it never feeds back to the grid, because it means that batteries can charge via off-peak electricity and switch to discharging to fulfill local demand during grid peak times. It has pretty much the same system effect as discharging into the grid during peak demand but it's more efficient to use the electricity at the same point it was stored.
  - greglindahl 10y ago
    Solar peaked at 8% of total production today, which looks like it matches the comment you're replying to: "At modest levels of penetration..."
  - philipkglass 10y ago
    Even in summer in California solar peaks mid-day while demand peaks in early evening. Nevertheless, it appears that the additional costs and efficiency loss from cycling fossil plants is dwarfed by the fuel-consumption savings, at least up to modest (33%) penetration of solar/wind: https://www1.eere.energy.gov/wind/pdfs/55588.pdf https://www1.eere.energy.gov/wind/pdfs/55588.pdf In this study, we found that up to 33% of wind and solar energy penetration increases annual cycling costs by $35–$157 million in the West. From the perspective of the average fossil-fueled plant, 33% wind and solar penetration causes cycling costs to increase by $0.47–$1.28/MWh, compared to total fuel and variable operations and maintenance (VOM) costs of $27–$28/MWh. The impact of 33% wind and solar penetration on system operations is to increase cycling costs but also to displace annual fuel costs by approximately $7 billion. The modeling assumptions in that study look pretty reasonable to me. The one significant change I'd make is plugging in a lower natural gas price, e.g. the $3.66/MMBtu from Henry Hub a week ago, compared to $4.60 assumed in the study. Even with that change it looks like fuel savings dwarf cycling costs.
  - tedsanders 10y ago
    This is such a frustrating misconception. The annual peak is far more important than the daily peak for capacity planning. There are two capacity issues being confounded here: (1) Generation capacity. The idea here is that if solar doesn't generate during peak loads, then building solar will not displace power plant capacity. But solar does generate during peak loads, so building solar does reduce the number of natural gas plants you need. At higher levels of PV penetration this will be a concern, but we're not there yet. (2) Ramping capacity. The idea here is that solar generation is correlated and non-dispatchable, so dispatchable generation must be able to match the swings in solar output. Again, this will be a concern at higher penetrations, but right now the grid can handle it. Philipkglass's replies are excellent.
  - ZeroGravitas 10y ago
    You've already got a couple of good replies, but I just wanted to be clear about how far you've missed the point of what you're replying to. His point was that the absolute peak of the system is in the afternoon during the summer. Which is when solar is most effective, so it shaves this peak quite well. It's like profiling your application and finding the hotspot, that's the place you most want to fix. It'll not only generate some energy that's needed, it will save you building a whole extra plant that's only needed for a few hours a year, if it's distributed then it'll save you upgrading transmission for a peak that's only needed a few hours a year. You talk about today, which is in mid December, which in places that use air-con means the peak load today is about 1/3 or so of the peak in the summer. California has more than enough power plants to supply the load in the winter even if all solar was unplugged suddenly. That was the whole point of what you replied to.
TillE 10y ago
There won't be many "batteries" when renewables are supplying most power. We have fairly cheap solutions for large-scale energy storage like hydroelectric with pumps.
- ztratar 10y ago
  You're far from correct. Large-scale energy storage is one of the biggest unsolved problems today, and there are numerous startups in the space. LightSail is an interesting one, and is using compressed air combined with micro-droplets of water to ensure stable, efficient energy transfer. Renewables success is heavily tied to battery technology. The wind isn't always moving and the sun isn't always shining, so you need to store that energy. Right now with existing battery tech, most of the energy is lost in a storage process due to heat or battery wear/tear. If energy storage was solved today, the oil/gas industry would be on their knees.
  - maxerickson 10y ago
    China is installing an 800MW-h vanadium flow battery: http://www.forbes.com/sites/jamesconca/2016/12/13/vanadium-flow-batteries-the-energy-storage-breakthrough-weve-needed/ http://www.forbes.com/sites/jamesconca/2016/12/13/vanadium-f... The cost claimed for a small installation coming online in Washington is $0.05 per kilowatt hour. That might not be cheap enough to beat out fossil fuel generation, but it is cheap enough to run the world on.
  - Gibbon1 10y ago
    If one runs the numbers, Pumped Heat Electrical Storage should work fine for time shifting energy at scale. None of the technology needed is at all novel or untested. All of the technologies needed scale up very well. Basically you store electric power as heat using motor/generators and axial flow compressors/turbines. Storage media is 'a big steel tank of hot rocks'. One can quibble but the end to end efficiency is going to be better than 60%. Could be as high as 80%. Far as I understand the reason such doesn't exist is there is no current market need until you have excess peak solar or wind power.
- barney54 10y ago
Steko 10y ago
It's not all that misleading when they actually take the time to make the same point and the article does this in at least three places.

DesiLurker 10y ago

with grid tie-in your grid is the battery.

philipkglass 10y ago

At modest levels of penetration it doesn't matter much that solar is non-dispatchable. There's already enough spare capacity in the system that you don't need to build backup specifically for solar. Consider, for example, the tens-of-gigawatts CAISO demand gap between 3:00 AM in April and 6:00 PM on the hottest day of August. The system already had to be ready for the peak-demand situation. Adding solar to the grid doesn't require new dispatchable backup capacity until penetration rises significantly. The backup capacity that was there before solar is a sunk cost. You might as well say that calling nat gas cheaper than solar is misleading because a valid comparison would require carbon capture and storage on the fossil plants.

barney54 10y ago
Solar did not help meet peak demand today in California: http://www.caiso.com/Pages/TodaysOutlook.aspx http://www.caiso.com/Pages/TodaysOutlook.aspx Nor does solar help meet peak demand for 2/3rds of the year because peak demand comes after the sun goes down. Solar can help during some summer days, but for much of the year it makes the system less efficient by requiring more ramping up and down of other generation resources.
- teach 10y ago
  Once we get our Tesla Powerwall batteries, that should help with peak demand, no?
  - Symmetry 10y ago
    Only if they sell power back onto the grid when there's more demand than can be met. Which is a doable thing but we don't have the framework quite in place yet.
    - philipkglass 10y ago
      Localized storage on households and businesses can help even if it never feeds back to the grid, because it means that batteries can charge via off-peak electricity and switch to discharging to fulfill local demand during grid peak times. It has pretty much the same system effect as discharging into the grid during peak demand but it's more efficient to use the electricity at the same point it was stored.
- greglindahl 10y ago
  Solar peaked at 8% of total production today, which looks like it matches the comment you're replying to: "At modest levels of penetration..."
- philipkglass 10y ago
  Even in summer in California solar peaks mid-day while demand peaks in early evening. Nevertheless, it appears that the additional costs and efficiency loss from cycling fossil plants is dwarfed by the fuel-consumption savings, at least up to modest (33%) penetration of solar/wind: https://www1.eere.energy.gov/wind/pdfs/55588.pdf https://www1.eere.energy.gov/wind/pdfs/55588.pdf In this study, we found that up to 33% of wind and solar energy penetration increases annual cycling costs by $35–$157 million in the West. From the perspective of the average fossil-fueled plant, 33% wind and solar penetration causes cycling costs to increase by $0.47–$1.28/MWh, compared to total fuel and variable operations and maintenance (VOM) costs of $27–$28/MWh. The impact of 33% wind and solar penetration on system operations is to increase cycling costs but also to displace annual fuel costs by approximately $7 billion. The modeling assumptions in that study look pretty reasonable to me. The one significant change I'd make is plugging in a lower natural gas price, e.g. the $3.66/MMBtu from Henry Hub a week ago, compared to $4.60 assumed in the study. Even with that change it looks like fuel savings dwarf cycling costs.
- tedsanders 10y ago
  This is such a frustrating misconception. The annual peak is far more important than the daily peak for capacity planning. There are two capacity issues being confounded here: (1) Generation capacity. The idea here is that if solar doesn't generate during peak loads, then building solar will not displace power plant capacity. But solar does generate during peak loads, so building solar does reduce the number of natural gas plants you need. At higher levels of PV penetration this will be a concern, but we're not there yet. (2) Ramping capacity. The idea here is that solar generation is correlated and non-dispatchable, so dispatchable generation must be able to match the swings in solar output. Again, this will be a concern at higher penetrations, but right now the grid can handle it. Philipkglass's replies are excellent.
- ZeroGravitas 10y ago
  You've already got a couple of good replies, but I just wanted to be clear about how far you've missed the point of what you're replying to. His point was that the absolute peak of the system is in the afternoon during the summer. Which is when solar is most effective, so it shaves this peak quite well. It's like profiling your application and finding the hotspot, that's the place you most want to fix. It'll not only generate some energy that's needed, it will save you building a whole extra plant that's only needed for a few hours a year, if it's distributed then it'll save you upgrading transmission for a peak that's only needed a few hours a year. You talk about today, which is in mid December, which in places that use air-con means the peak load today is about 1/3 or so of the peak in the summer. California has more than enough power plants to supply the load in the winter even if all solar was unplugged suddenly. That was the whole point of what you replied to.

TillE 10y ago

There won't be many "batteries" when renewables are supplying most power. We have fairly cheap solutions for large-scale energy storage like hydroelectric with pumps.

ztratar 10y ago
You're far from correct. Large-scale energy storage is one of the biggest unsolved problems today, and there are numerous startups in the space. LightSail is an interesting one, and is using compressed air combined with micro-droplets of water to ensure stable, efficient energy transfer. Renewables success is heavily tied to battery technology. The wind isn't always moving and the sun isn't always shining, so you need to store that energy. Right now with existing battery tech, most of the energy is lost in a storage process due to heat or battery wear/tear. If energy storage was solved today, the oil/gas industry would be on their knees.
- maxerickson 10y ago
  China is installing an 800MW-h vanadium flow battery: http://www.forbes.com/sites/jamesconca/2016/12/13/vanadium-flow-batteries-the-energy-storage-breakthrough-weve-needed/ http://www.forbes.com/sites/jamesconca/2016/12/13/vanadium-f... The cost claimed for a small installation coming online in Washington is $0.05 per kilowatt hour. That might not be cheap enough to beat out fossil fuel generation, but it is cheap enough to run the world on.
- Gibbon1 10y ago
  If one runs the numbers, Pumped Heat Electrical Storage should work fine for time shifting energy at scale. None of the technology needed is at all novel or untested. All of the technologies needed scale up very well. Basically you store electric power as heat using motor/generators and axial flow compressors/turbines. Storage media is 'a big steel tank of hot rocks'. One can quibble but the end to end efficiency is going to be better than 60%. Could be as high as 80%. Far as I understand the reason such doesn't exist is there is no current market need until you have excess peak solar or wind power.
barney54 10y ago

Steko 10y ago

It's not all that misleading when they actually take the time to make the same point and the article does this in at least three places.