5 MWh Battery!

CALLDCALLD Solar Expert Posts: 230 ✭✭
This news is meant to impress:


I suppose they have to start somewhere don't they? But when compared to the amount of renewable energy Germany has installed to date it's a bit like using your cellphone battery to smooth out the electrical load of your house isn't it?

Is this any better than using pumped storage or flywheel storage when talking about utility scale power?


  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: 5 MWh Battery!

    Not sure about flywheel storage, but pumped water storage requires an available reservoir with a suitable head difference. And has an overall conversion/storage efficiency under 50%.
    Batteries can do a lot better than that.
    One of the problems with flywheel storage is the energy density you can reach and the difficulty of either building very large flywheels or packaging large numbers of small units to get the total energy storage you need.

    I did see one proposal for pumped storage that used a relatively short (~20 stories) shaft and a very heavily weighted piston on top of the water column to allow for a relatively constant head pressure as the height of the water column changed.

    For buildings in areas with large A/C loads in summer, systems have been produced that use ice as a cooling energy storage medium to time shift the A/C load into off-peak hours. Unfortunately that does not align well with solar PV. :(
    SMA SB 3000, old BP panels.
  • CALLDCALLD Solar Expert Posts: 230 ✭✭
    Re: 5 MWh Battery!

    I suppose every technology has it's limitations. Yes I can see the advantage Li-ion has in terms of efficiency. Still power must be converted from AC to DC and then back to AC, probably changing voltage as well. Then of course unless it's LiPoFe4 the cycle life will be an issue for utility companies who typically design systems for 20-50 years plus.

    A 5MWh battery could at best provide load leveling for one moderately sized town of no more than several thousand households, the capacity being about the same as one large wind turbine producing nameplate capacity for one hour. Pumped storage capacity can me measured in GWh by comparison. Flywheel technology already provides very short-term load leveling for some utility companies, the high power density and instant response times being the advantage over high energy density of batteries.

    A 40MWh lead acid battery was already constructed long before this one to test the technology of battery load leveling, it did what it was supposed to do but never became a big hit...
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