3 ms·

4 hours of storage is enough for a PV system to serve the early-evening period when demand is at its highest. For example, here's the demand curve for Californ

4 hours of storage is enough for a PV system to serve the early-evening period when demand is at its highest. For example, here's the demand curve for California's CAISO today: http://www.caiso.com/TodaysOutlook/Pages/default.aspx http://www.caiso.com/TodaysOutlook/Pages/default.aspx The peak demand is between 6 and 7 PM. Since the sun sets at 4:55 PM today in Los Angeles, and solar output dips significantly starting a couple of hours before sunset, solar cannot supply any of the peak-demand load at this time of year. Even with later sunsets in the summer, solar can supply only a fraction of peak-period demand. But solar coupled with 4 hours of storage can cover the most important hours just before and just after sunset. By the later evening, demand is lower and wind output has often increased. The two most interesting cases: Standalone 100-MW PV system with one-axis tracking ($111 million) -- this is a pretty typical configuration for a new solar farm being built today. Co-located, AC-coupled PV (100 MW) plus storage (60 MW/240 MWh, 4-hour duration) system ($188 million) -- this is a battery system plus the solar farm at the same facility. AC coupling is a little bit more expensive than DC coupling but it is more flexible; it can be installed as part of the original solar project or as a retrofit. Most utility scale PV projects that are already built have ample room for a battery system on the same site. A year ago, XCel Energy in Colorado received median bids of $36/MWh ($0.036/kWh) for PV plus 4 hours of storage: https://www.greentechmedia.com/articles/read/record-low-solar-plus-storage-price-in-xcel-solicitation https://www.greentechmedia.com/articles/read/record-low-sola... However, those bids are for projects to be completed in 2023 and NREL's cost estimates are for projects built now. That can explain part of why NREL's cost premium for adding storage appears to be higher than the premium assigned in recent auctions.

Retric 8y ago
Shifting power east / west is another option. Supplying Florida with solar from California can significantly reduce the need for storage. This also allows you to supply morning power in California with solar in Florida. The interactions are complex enough I think production, transmission, and storage all need to be dealt with separately.
- philipkglass 8y ago
  Long-distance grid connections are technically viable and can reduce the need for storage. The biggest problem in the US is the very slow and uncertain process of getting state-by-state approval for interstate transmission projects. A Florida-California transmission project would need approval from at least 8 states. The proposed Grain Belt Express transmission project goes through only 3 states and received its first approval (in Kansas) 7 years ago. It is still trying to get the necessary approvals in Missouri. Due to this drawn-out process in Missouri, opponents in Illinois were able to reverse the project's earlier-obtained Certificate of Public Convenience and Necessity. Even if Missouri gets on board the project will have to re-obtain approval in Illinois, and perhaps by the time that's over Kansans will have new objections.
  - tsukikage 8y ago
    JOOI, who is the opposition, and why are they opposing this?
    - pjc50 8y ago
      Appears to be the usual mix of NIMBYs and anti-eminent-domain activists: http://enquirerdemocrat.com/grain-belt-express-project-halted-courts/ http://enquirerdemocrat.com/grain-belt-express-project-halte...
- cure 8y ago
  There is a long-distance transmission line in California that is used a bit like this, allowing the use of power from the North in the South in summer when peak demand is there, see https://en.wikipedia.org/wiki/Pacific_DC_Intertie https://en.wikipedia.org/wiki/Pacific_DC_Intertie The Pacific DC Intertie is not nearly as long as a connection between CA and FL would be. In that scenario, transmission losses would be quite significant. The cost of building and maintaining the line would also be quite high.
- eigenvector 8y ago
  Although transmission does help alleviate the problem, the nature of building new linear infrastructure is that it will take much more time and risk to complete a transmission megaproject than to simply build more storage where it's needed.
wbl 8y ago
Meanwhile NJ has 50% of all electricity carbon free.
- philipkglass 8y ago
  As of 2017 California is at 50.45% carbon-free electricity: https://www.energy.ca.gov/almanac/electricity_data/total_system_power.html https://www.energy.ca.gov/almanac/electricity_data/total_sys... That's summing up nuclear, large hydro, and renewables excluding biomass from the California Power Mix column.

Retric 8y ago

Shifting power east / west is another option. Supplying Florida with solar from California can significantly reduce the need for storage. This also allows you to supply morning power in California with solar in Florida. The interactions are complex enough I think production, transmission, and storage all need to be dealt with separately.

philipkglass 8y ago
Long-distance grid connections are technically viable and can reduce the need for storage. The biggest problem in the US is the very slow and uncertain process of getting state-by-state approval for interstate transmission projects. A Florida-California transmission project would need approval from at least 8 states. The proposed Grain Belt Express transmission project goes through only 3 states and received its first approval (in Kansas) 7 years ago. It is still trying to get the necessary approvals in Missouri. Due to this drawn-out process in Missouri, opponents in Illinois were able to reverse the project's earlier-obtained Certificate of Public Convenience and Necessity. Even if Missouri gets on board the project will have to re-obtain approval in Illinois, and perhaps by the time that's over Kansans will have new objections.
- tsukikage 8y ago
  JOOI, who is the opposition, and why are they opposing this?
  - pjc50 8y ago
    Appears to be the usual mix of NIMBYs and anti-eminent-domain activists: http://enquirerdemocrat.com/grain-belt-express-project-halted-courts/ http://enquirerdemocrat.com/grain-belt-express-project-halte...
cure 8y ago
There is a long-distance transmission line in California that is used a bit like this, allowing the use of power from the North in the South in summer when peak demand is there, see https://en.wikipedia.org/wiki/Pacific_DC_Intertie https://en.wikipedia.org/wiki/Pacific_DC_Intertie The Pacific DC Intertie is not nearly as long as a connection between CA and FL would be. In that scenario, transmission losses would be quite significant. The cost of building and maintaining the line would also be quite high.
eigenvector 8y ago
Although transmission does help alleviate the problem, the nature of building new linear infrastructure is that it will take much more time and risk to complete a transmission megaproject than to simply build more storage where it's needed.

wbl 8y ago

Meanwhile NJ has 50% of all electricity carbon free.

philipkglass 8y ago
As of 2017 California is at 50.45% carbon-free electricity: https://www.energy.ca.gov/almanac/electricity_data/total_system_power.html https://www.energy.ca.gov/almanac/electricity_data/total_sys... That's summing up nuclear, large hydro, and renewables excluding biomass from the California Power Mix column.