3 ms·

I haven't seen an estimate done for the US, but for Germany one estimate is that to rely on solar and wind would require about 6,000 pumped storage plants whic

• Retric 4y ago
  That’s exactly the kind of meaningless and inflated number I was talking about. Notice how they exclude hydroelectric dams. Existing hydroelectric dams currently store vastly more energy than the average pumped hydro facility and they can easily be adapted to add additional turbines for relatively minimal costs. Collectively North American dams are storing at a minimum several days of total grid output and theoretically much more depending on how you do the calculation. Adding turbines doesn’t increase annual production, but it does increase flexibility as it makes minimal difference to discharge 1x water for 24 hours or 5x water for 4 hours and the rest over the other 20. Several dams have already been retrofitted like that as peaking power plants are simply vastly more valuable per kWh. It’s even better for the environment as rivers naturally have significant variability which is normally smoothed out by dams. PS: Rarely mentioned in those kind of analysis is how sensitive the required storage number is to the exact mix and oversupply of wind/solar. A grid with 1.001x average annual demand looks very different than one with say 1.1 or even 2x.