spectastic

I know. I was referring to the desalination plants they want to build in ca to combat shortages. I just think it's funny how some people think it's a good idea to use fresh water to make energy

Flatballer

Pumped storage has been around a really long time. Not sure why you'd use a giant cylinder. Just have two reservoirs, one above the other, with a generator in between. Run the generator as a motor during the day to pump from low to high with solar power (or at night with extra nuclear, which is what's currently done usually). Run it as a generator during the night when solar isn't generating (or during the day, to avoid using peaking plants, as is currently done).

Flatballer

If you want to kill someone and get away with it, use your car.

spectastic

Because a large weight can store orders of magnitude more potential energy per unit volume than water can. You won't need as much water or height to get the same amount of storage.

himespau 

Yeah, the people I talked to said that it was a river running into the ocean anyway so it wasn't being used, but I just thought about all that freshwater going to waste. Apparently there are a couple of plants in scandanavia doing it and I'd heard talk about one going in in Spain before the collapse destroyed their economy.

spectastic

There are also people who believe in fuel cells, which is like solar energy but way more Inefficient. And compressed air cars, which have less energy density than lead acid batteries. There are a lot of bad investments out there

topflightpro

This morning, I had to turn on the space heater in my office because it was so cold in her. I turned it off around noon, and now I have the fan going to cool things off.

Flatballer

I see. So they're using the water as a hydraulic fluid essentially. Still, space isn't really a concern where you would normally put a pumped storage. I can build a really giant lake a lot easier than I can manufacture a gigantic weight. I guess that's why nobody has built one yet.

And it's not orders of magnitude, it's one order. Lead is 11g/cm3 specific gravity and potential energy is linear. Maybe I'm missing something, Do you have a link, I'd like to read it.

himespau 

Every winter my office is usually 75+ and I often end up sweating. In the summers, they keep it below 65 (often below 60), so I have a stack of sweaters of varying thickness and color that I keep around for summertime. At least in the winter I can open the windows to cool the place off. Come summer that lets too many bugs in (no screens). Ultraefficient use of energy by a university struggling with financial issues and facing another 10% cut in state funding.

spectastic

Ok one order. Anyway, wold you rather prop up a lake or a building 1 10th the size? When scaled up, the economy of scale takes over. We.re talking huge structurez. Take the energy need of a city, make up a reaaonable height, select a cheap dense material, take out some efficiency loss, and see how big it needs to be. It was just a YouTube thing. I'm sure there are other stuff on it. But this is something I can only expect to come from tax money.

Flatballer

Alright, I have nothing better to do. Someone might need to check my math, I don't do this sort of thing much anymore.

Let's say we want to replace a good size central plant. So let's say 1000 MW. We'll assume we'll run it down 8 hours a day, and charge it 8 hours a day, and it sits still the other 8 in between the peaks and the valleys. So 8 hours x 1000 MW is 8000 MWh. 8000 MWh is approximately 2.88e10 kJ. At this point efficiency is a rounding error in my back of the envelope, so whatever. 500m is an extremely tall building, but I think we're gonna need it. That's the size of Taipei 101, for reference. So that gives us a mass of 5.88e9 kg. I have no idea how much that is, so let's see.

Lead has a density of approx 11,000 kg/m3. So we'll need about 5.3e5 cubic meters of lead. If we make the plate 50 meters thick (a really, really thick plate of lead, but I think we'll need it) we need about 10000 square meters of lead. That's about 2.5 acres of lead.

I think we'd have less engineering problems if we didn't build it so high. So let's say 50m (still pretty darn tall), you'd need 25 acres of 50 meter thick lead. But if the lead is 50 meters thick, we actually need to be 100 m tall, in order to raise it high enough, hmm. So maybe only 25m thick (still a really, really thick plate of lead that is probably impossible to actually manufacture) we'll need an area of 50 acres, and 50 meter high structures.

Obviously you could break it up into smaller plates instead of one giant one. And you could stack 1m thick plates instead of casting one giant one. You're probably reasonably looking at 150 acres or so of lead getting raised up and down. I think I'd rather have a lake. I can make a lake really deep really easily, and I can make it much, much higher than the lower lake by building it on a hillside. I guess you could slide your lead up and down a hillside or a mountain, on tracks or something, to prevent your huge freestanding structure issues.

big john

Was it an objection? I certainly meant her no disrespect, just trying to be funny. Connie is, of course, one of the top women cyclists ever produced by this country.
Here she is with the legendary Eddie B.

spectastic

I'm sure theres a way to calculate the wh per kg or per l, to compare with energy density of existing lithium ions. That would be interesting to see. Unfortunately, I am not motivated enough to pick up pen and paper like you are.

I'm sure there are 25 or even 50 acres Of Land can be found somewhere that's close to water. We.ll just put those in the solar farms, perhaps put some of the panels on top of the structures to conserve space.

Also 8000mwh is a pretty siZabel plant. Quick search yields that it would support close to 1 mil people. I guess it's not even that much...

The lake idea also has challenges though. We're talking moving an entire lake.. that's 10x more water than the lead idea.

Stick to power wall idea I say

therhodeo

Indeed.

Flatballer

I picked 1000 MW because it was a round number. Duke Energy has a few pumped storage hydro facilities that are in the 800 MW range, so 1000 MW isn't crazy high for something like this.

spectastic

Interesting. You know how long they've been operating?

I had no idea this was already a thing..

Flatballer

https://www.duke-energy.com/power-pl...rage-hydro.asp

Bad Creek is 1065MW, started generating in 1991. Jocassee is 710MW, started generating in 1973. Looks like those are the only two pumped storage, I was thinking there were three. They're both there to take the excess power from the nearby nuclear stations at night when it isn't needed.

Doge

I raced his mom in Acton RR. The genes come from the mom - good association.

Hermes

@Flatballer @spectastic A good source of information on how different power plant technologies work (as well as anything relating to electric power generation, transmission and distribution) is EPRI. EPRI is the R&D association for the US electric utility industry and over the years, they have evaluated "all" technologies that had possible application to electric power production. Pumped energy storage is used to optimize an electric grid system. Here is an article from EPRI that discusses their use and the results from utilities operating on different grids in the US. One can download the report in its entirety.

shovelhd

I raced Davis in Boston. Sorta.

Homebrew01

Sound like another perpetual motion attempt.

Homebrew01

Me too. When 7-11 and Megoni were in town I just hung on for dear life until getting pulled.

Homebrew01

Nah, just thought it amusing.

carpediemracing 

Was that when Nitz placed top whatever, like 5th? I think Dave Geissert got 10th there, first "local" amateur rider to place, based on Nitz being Mengoni?

Back then Mengoni was a powerhouse team. Bauer I think raced for them at one point, Lemond?, Matt Eaton, other top top top top US riders.

shovelhd

Hah. I finished.