5 ms·

You don't need pump storage when you have 60% hydro, all you need is to change the rate of production. When the sun shines so the shops run out of sunscreen and

• C1sc0cat 8y ago
  Pumped storage is for managing peak demand - you can go from zero to huge amounts of power very very quickly and avoid using the expensive and polluting standby by capacity.
  • Arnt 8y ago
    I'm curious. If you have 60% hydro, you have a lot of water coming into the reservoirs from snow melt. Why would you bother with pumping up more water from below?
    • reubenmorais 8y ago
      They might not be able to change production quickly enough in hydro plants to serve daily demand peaks, or the peaks might be higher than the total produced amount from the 60% hydro.
    • Aromasin 8y ago
      There's rarely ever enough water coming from upstream to counter the huge amount of water that gets dumped during peak energy consumption hours. If you've got extra grid power left over that's not being used during trough hours and it's not used to refill the reservoir, or stored in some other way (lithium-ion batteries, hydrogen gas production etc.) it's just going to go to waste.
      • Arnt 8y ago
        I see. That doesn't apply to the present subject though; Idaho uses mostly snow, and for a reservoir that buffers most of a winter's snow, a day's peak/trough energy consumption is a rounding error.
      • kortilla 8y ago
        >There's rarely ever enough water coming from upstream Not the case in Idaho
  • gnode 8y ago
    Pumped storage is just hydro, with the ability to replenish the reservoir artificially. If you have sufficient natural flow there's no need to pump anything into it. The idea of pumped storage being for reserved for peak demand comes from the typically limited size of artificial reservoirs making it such that it can only be used for peak demand.
    • thaumasiotes 8y ago
      > If you have sufficient natural flow there's no need to pump anything into it. So in this model, Idaho will move to 100% renewable energy by draining everyone downstream to 0%?
      • foxhop 8y ago
        Most of the water still moves down stream. You only pump upstream while the sun is out _and_ you have spare capacity from solar. Essentially you use the reservoir on the top of the dam as a battery. You charge it up when you have extra energy capacity.
      • gnode 8y ago
        > draining everyone downstream to 0% I don't see how that follows. Hydroelectric power use doesn't destroy water. Minus some evaporation, all water upstream makes its way downstream whether the gravitational potential energy is converted to electricity or wasted like normal. When building a dam, there's a temporary and arbitrarily small reduction in downstream flow as the reservoir is accumulated, but the more significant issue is usually permanent upstream flooding. Regardless, my understanding is that Idaho is planning to increase its use of solar to make its way to 100%, with hydro being used to balance the supply-demand discrepancy. I would expect any hydro capacity to already be fully utilised on a long term basis.
        • thaumasiotes 8y ago
          It doesn't destroy the water, but it does destroy the flow. More hydroelectric power generation upstream means less use of the river downstream, because it's been pacified into a long pond. This is an area of serious contention in many places, particularly where rivers cross national boundaries. > wasted like normal But the river flow is not normally wasted. Everyone along a river uses it. In particular, if you're willing to assume (correctly) that generating hydroelectric power in Idaho drains gravitational potential energy out of the river -- in Idaho -- then it immediately follows that the people downstream won't be able to generate hydroelectric power from the river, because the energy was all drained out in Idaho. Which is what I said in the first place.
• Obi_Juan_Kenobi 8y ago
  There are limits to how much you can do this. For river health, you need to maintain roughly even outflows. Too much release results in flooding, and too little will dry up the river. But even outside of those extremes, you can have issues where high outflows inundate levies, followed by reduced outflows that lower the river, causing the soaked levies to collapse into the river. There are also fishery-health issues to consider. How much of an issue this is depends on what the situation is downstream; some damns have afterbays that can moderate these changes quite well, while others do not and are less able to rapidly change outflows like this. Basically, you might need to do some significant upgrades before you can use your hydro 'on demand' like this.