A $3B Plan to Turn Hoover Dam into a Giant Battery

Also they fail to mention cyclic efficiency and life cycle cost. Hydrolic storage are most efficient with their short comingss being too large and location dependaance.

The 26 cent figure for a kWh of storage must be the cost per cycle, and assuming it gets thousands of cycles. 1 kWh of Li-ion battery capacity is orders of magnitude more expensive than 26 cents.

26/15 is the estimated cost per kwh. Really there is a huge variance, especially for pumped storage because because of highly variable capital cost.

Capital costs are in the 100s-1000s dollars for kw of pumped storage.[0]

[0]http://large.stanford.edu/courses/2014/ph240/galvan-lopez2/

Funny I used to think of capacitor as water bucket and now we're smoothing power grid with a big water bucket.

Northfield Mountain is a great plant. The company I work for used to own it before we foolishly sold it off. A pension plan bought it, which is a good indication of how stable it's economic outlook is. It's also an important black-start resource in the northeast.

The difference between Northfield and Lake Mead / Hoover Dam is that dedicated pumped-storage plants have two reservoirs: upper and lower. They are generally able to move water between them as needed with few restrictions because there is no downstream water user who's going to suffer damage because water was released from the upper reservoir (or taken from the lower reservoir).

The Colorado River is pretty much the ultimate opposite case. The existing Hoover Dam operations are dictated entirely by downstream flow requirements. If water has to flow downstream (because it's needed by agricultural users), it flows, and power generation follows. If flow needs to be restricted for flood control, power generation is reduced accordingly. Other than emergency spillways, there's no way for water to flow downstream except through the turbines, so there's no flexibility based on the needs or conditions of the power grid. In power industry terminology this is called a 'must-run' resource.

This article doesn't address that at all, although I imagine that if there is a serious engineering paper proposing this that it would look at the consequences of this in detail. It's extremely questionable to invest this scale of money in an energy storage resource that will likely never attain its full operational potential because the operator would not be allowed to ramp up or down arbitrarily. Batteries are more expensive - right now - but far less risky and can easily be deployed to any location, in precisely the size and scale required, with minimal financial risk or exposure to changing climate patterns.

The water is pumped from lower down the river to higher up the river.

No water is lost in the process - you can still use that same water for feeding almond trees or whatever you guys like to use it for.

At Hoover Dam, 100% of the river flows through the turbines with no bypass. The dam was originally built for flood control. Power generation is driven by downstream water demands. [1]

[1] https://en.wikipedia.org/wiki/Hoover_Dam#Operation

"The entire flow of the Colorado River passes through the turbines."

FTA:

> The Los Angeles Department of Water and Power, the nation’s largest municipal utility, says its proposal would increase the productivity of the dam, which operates at just 20 percent of its potential, to avoid releasing too much water at once and flooding towns downstream.

From Wikipedia, https://en.wikipedia.org/wiki/Hoover_Dam#Operation:

> The amount of electricity generated by Hoover Dam has been decreasing along with the falling water level in Lake Mead due to the prolonged drought in the 2010s and high demand for the Colorado River's water. Lake Mead fell to a new record low elevation of 1,071.61 feet (326.63 m) on July 1, 2016 before beginning to rebound slowly.[95] Under its original design, the dam will no longer be able to generate power once the water level falls below 1,050 feet (320 m), which could occur as early as 2017. To lower the minimum power pool elevation from 1,050 to 950 feet (320 to 290 m), five wide-head turbines, designed to work efficiently with less flow, were installed.[96] Due to the low water levels, by 2014 it was providing power only during periods of peak demand.[97]

Which is really surprising.

This might sound insane, but the great lakes might work, with a joint Canada-US plan. Raising one of them by a foot would be all you'd need because their area is so huge.

If you're willing to look outside the US, a wild but interesting mega project might be to try to do the same thing with the South Aral Sea. Pump water all the way from the Caspian. The North Aral is cut off by a dam/dyke and the south Aral barely exists anymore, causing major economic harm. Fill it with salt water and salt water fish to revive the fishing economy while using it as a giant battery.

The Salton Sea.

Death Valley or Crater Lake also would be good, but likely would face opposition from almost every American.

https://en.wikipedia.org/wiki/Oroville%E2%80%93Thermalito_Co... is in northern California.

"Water released for power in excess of local and downstream requirements is conserved by pumpback operation during off-peak hours through both powerplants into Lake Oroville to be subsequently released for power generation during periods of peak power demand. The Plant has 4 units: 1 generating unit and 3 pumping–generating units, with an installed capacity of 120 MW, maximum flow rate of 17,400 cu ft/s (490 m3/s).[5]"

Summer days are always dry and sunny, so a large solar array might work well here.

When there is a dam already producing electricity, you just reduce the flow through the dam rather than pumping the water back uphill. That is by far the most efficient way to handle excess generation from other sources in this case. This is a politically driven proposal whose implementation will be a boon to private producers at the expense of taxpayers.

Pump storages are already all over Europe for decades. The most famous one being Kaprun/Austria, built by the Nazis in the 30ies. They are all over the Alps, as the green party lets them.

Those pump storages provide the very expensive peek electricity all over Europe, needed for the spikes in the morning and noon.

Nevada probably didn't need it back then, Hoover Dam was built for flood protection, and since then the levels are too low to work efficiently as pump storage. But since peek energy is in high demand they think it over.

Many of the Fallout games are indeed set in the western half of the US :)

If you've not been to Hoover Dam, it's spectacular. Not just the engineering, but the gorgeous art deco everywhere which has been preserved rather than 'modernized'.

My guess is to get an economically height difference to the dam.

If you look at the topography of the area in google maps you will see that the sides of the canyon are somewhat steep and rugged for quite a ways downstream of the dam. Go a bit further and you find Willow Beach, which has a nice flat run north and then west back to the reservoir. I am guessing that being able to run the pipe using trenching equipment rather than tunneling through canyon walls is a big advantage.

It depends an awful lot on the lag between demand and excess supply. It might use the noon sun to pump water that was used to meet morning demand.

Pumped-storage hydro[1] is an established concept and is in active use all over the world (Europe, US, Japan, ...).

Austria for example has a lot of hydro (over 70% of total production!) including multiple pumped-storage installations.

There's huge excess capacity at night here thanks to all the hydro, so you might as well use it for something useful.

[1] https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

The proposal isn’t to use the dam’s excess power to pump the water back uphill. They want to use excess power from other solar and wind plants to effectively store any excess energy that they produce. Since these alternative sources cannot consistently produce energy 24 hours per day, and the times that they are able to produce it do not necessarily match up with consumer demand, they need to store it somehow. This is being proposed as a more efficient and cost effective form of storage than batteries (though I am curious how much energy will be lost due to evaporation after the water has been pumped in Hoover dam’s hot climate and other inefficiencies).

It is quite common in Europe and in fact Switzerland has a few just for that purpose (Pumpspeicherkraftwerk). Interactive Map [1]

[1] http://www.uvek-gis.admin.ch/BFE/storymaps/WK_WASTA/index.ph...

Don't call things you don't understand stupid. Ask for explanation, then you can (sometimes) do a judgement.

I'm not sure why you are being downvoted, you are correct. If the normal state of the dam is to generate electricity then the obvious response to excess supply is to stop the flow. No need to pump anything back uphill unless the excess exceeds the normal capacity of the dam.