6 ms·

By which you mean, of course, the least difficult part, and the part that is needed only after all the hard parts, the ones that actually produce energy in usef

by ncmncm 4y ago

By which you mean, of course, the least difficult part, and the part that is needed only after all the hard parts, the ones that actually produce energy in useful form, have been built out.

Manuel_D 4y ago
No, energy storage is a far more challenging task than generating it. To put this in perspective, the world uses 60TWh of energy per day. Most energy storage projects are in the hundreds of megawatt hour range, a few in the gigawatts. Estimated for a 100% renewable grid depends on the solar to wind ratio and degrees of overproduction, but they usually fall in the range of 12-24 hours for a 0 carbon grid. And that figure of 60 TWh is only going to grow as underdeveloped countries become more wealthy and want A/C and other amenities. This is a colossal amount of storage, far outside the bounds of existing storage methods. Hence why plans for a renewable grid assume untested mechanisms like power to gas or compressed air will just scale to near-infinity.
- ncmncm 4y ago
  In fact energy storage is a trivial matter of high-school-level physics. Most existing storage, taking advantage of existing hydro-power dams, uses excess energy to force water up to the reservoir, which energy is later extracted by letting it flow out through a turbine. New pumped-hydro systems built just for storage will be radically cheaper than existing dams, and be practical in hundreds of times as many places: you just need a hilltop no one is using, and water to pump up to it. The reservoir may be much cheaper than a hydro power dam because it does not need to contain high pressure; an earthen dike suffices. There are numerous other, equally simple methods, for places without enough hills or water. Synthetic fuels like hydrogen and ammonia are an attractive choice because tankage is cheap, and they are transportable and have myriad industrial uses, so after your tankage is full you can sell all further production. Of course one only builds storage after there is excess energy to put in it. We will need a lot of it, in time, but it is all just construction and mechanics: ordinary civil engineering. (If you have to lie about the practicality of storage in order to promote nukes, what does that really tell us about your nukes?)
  - Manuel_D 4y ago
    Fusion is trivial high school level physics, too. We all learn about the physics that goes on in the sun's core. You're right that hydroelectric offers lots of storage potential. But it's geographically limited. Great for countries like Norway that have lots of it. But countries that don't can't just summon dam-able mountain valleys. You need more than just a hilltop to build pumped hydro. You need a hilltop, with access to a water source. It also needs to be close to a transportation network otherwise construction costs will be prohibitively expensive. Pumped hydro plants do indeed cost a lot: the biggest one in the US in Bath County cost $4 billion dollars for a capacity of 24 GWh. Furthermore, it will get more expensive as it scales up: as the most accessible sites are developed, subsequent facilities have to be built in more and more suboptimal sites. > The reservoir may be much cheaper than a hydro power dam because it does not need to contain high pressure; an earthen dike suffices This makes absolutely no sense. I needs high pressure to generate electricity. Low pressure would mean there's hardly any potential energy to tap. If you're suggesting we have a tunnel leading out from under the reservoir, then those have to be built in exactly the right geography where there's an alpine lake with a height difference. > There are numerous other, equally simple methods, for places without enough hills or water. Yet, despite these methods purported simplicity you didn't actually specify them (Edit: you added a couple in an edit after I typed my reply). Because then you'd have to defend their viability. Since you edited in hydrogen and ammonia: * Power to hydrogen: electrolysis of water remains expensive, hence why most hydrogen is built with steam reformation. It's not just the electricity costs, but also maintaining the electrodes that perform the hydrolysis. * Power to Ammonia: this needs a source of hydrogen, so it shares all of the above's issues. Ammonia is really just a storage mechanism for hydrogen, actually producing usable energy from ammonia is done by releasing the hydrogen from the ammonia and then running it through a fuel cell. You're the one being overly optimistic about the practicality of storage. We've had excess production during peak renewable generation for close to a decade now. The excuse that we won't build storage until there's an excess of electricity isn't valid. Places like Hawaii and California already are saturating the energy market, but the storage is systems you propose aren't being built because they aren't feasible. Intermittent sources are fine to chip away at fossil fuel use, or in places with widespread hydroelectric power. But we can't kid ourselves into thinking that storage will make it feasible every. Grid scale energy storage should be approached like fusion: maybe it'll be invented and change the energy landscape. But it's foolish to treat that possibility as a given.

by ncmncm 4y ago

By which you mean, of course, the least difficult part, and the part that is needed only after all the hard parts, the ones that actually produce energy in useful form, have been built out.

Manuel_D 4y ago

No, energy storage is a far more challenging task than generating it. To put this in perspective, the world uses 60TWh of energy per day. Most energy storage projects are in the hundreds of megawatt hour range, a few in the gigawatts. Estimated for a 100% renewable grid depends on the solar to wind ratio and degrees of overproduction, but they usually fall in the range of 12-24 hours for a 0 carbon grid. And that figure of 60 TWh is only going to grow as underdeveloped countries become more wealthy and want A/C and other amenities. This is a colossal amount of storage, far outside the bounds of existing storage methods. Hence why plans for a renewable grid assume untested mechanisms like power to gas or compressed air will just scale to near-infinity.

ncmncm 4y ago
In fact energy storage is a trivial matter of high-school-level physics. Most existing storage, taking advantage of existing hydro-power dams, uses excess energy to force water up to the reservoir, which energy is later extracted by letting it flow out through a turbine. New pumped-hydro systems built just for storage will be radically cheaper than existing dams, and be practical in hundreds of times as many places: you just need a hilltop no one is using, and water to pump up to it. The reservoir may be much cheaper than a hydro power dam because it does not need to contain high pressure; an earthen dike suffices. There are numerous other, equally simple methods, for places without enough hills or water. Synthetic fuels like hydrogen and ammonia are an attractive choice because tankage is cheap, and they are transportable and have myriad industrial uses, so after your tankage is full you can sell all further production. Of course one only builds storage after there is excess energy to put in it. We will need a lot of it, in time, but it is all just construction and mechanics: ordinary civil engineering. (If you have to lie about the practicality of storage in order to promote nukes, what does that really tell us about your nukes?)
- Manuel_D 4y ago
  Fusion is trivial high school level physics, too. We all learn about the physics that goes on in the sun's core. You're right that hydroelectric offers lots of storage potential. But it's geographically limited. Great for countries like Norway that have lots of it. But countries that don't can't just summon dam-able mountain valleys. You need more than just a hilltop to build pumped hydro. You need a hilltop, with access to a water source. It also needs to be close to a transportation network otherwise construction costs will be prohibitively expensive. Pumped hydro plants do indeed cost a lot: the biggest one in the US in Bath County cost $4 billion dollars for a capacity of 24 GWh. Furthermore, it will get more expensive as it scales up: as the most accessible sites are developed, subsequent facilities have to be built in more and more suboptimal sites. > The reservoir may be much cheaper than a hydro power dam because it does not need to contain high pressure; an earthen dike suffices This makes absolutely no sense. I needs high pressure to generate electricity. Low pressure would mean there's hardly any potential energy to tap. If you're suggesting we have a tunnel leading out from under the reservoir, then those have to be built in exactly the right geography where there's an alpine lake with a height difference. > There are numerous other, equally simple methods, for places without enough hills or water. Yet, despite these methods purported simplicity you didn't actually specify them (Edit: you added a couple in an edit after I typed my reply). Because then you'd have to defend their viability. Since you edited in hydrogen and ammonia: * Power to hydrogen: electrolysis of water remains expensive, hence why most hydrogen is built with steam reformation. It's not just the electricity costs, but also maintaining the electrodes that perform the hydrolysis. * Power to Ammonia: this needs a source of hydrogen, so it shares all of the above's issues. Ammonia is really just a storage mechanism for hydrogen, actually producing usable energy from ammonia is done by releasing the hydrogen from the ammonia and then running it through a fuel cell. You're the one being overly optimistic about the practicality of storage. We've had excess production during peak renewable generation for close to a decade now. The excuse that we won't build storage until there's an excess of electricity isn't valid. Places like Hawaii and California already are saturating the energy market, but the storage is systems you propose aren't being built because they aren't feasible. Intermittent sources are fine to chip away at fossil fuel use, or in places with widespread hydroelectric power. But we can't kid ourselves into thinking that storage will make it feasible every. Grid scale energy storage should be approached like fusion: maybe it'll be invented and change the energy landscape. But it's foolish to treat that possibility as a given.