Reservoirs, no matter how 'artificial', still take up space, i.e. destroy habitat. Your statement that there is no need to endanger fish & wildlife is a little optimistic.

My understanding is that good sites for pumped storage schemes are actually few and far between.

Here in South Africa we have one operational scheme (the Palmiet pumped-storage scheme) that destroyed quite a lot of hugely species-diverse fynbos habitat.

There is a second scheme, currently under construction, that'll damage a unique percolation wetland that happens to be one of only 4 known places on the planet that the endangered White-winged Flufftail (a bird) spends the non-breeding season (the critter breeds in a couple of wetlands in Ethipia and is on the verge of extinction). Google 'Braamhoek Flufftail' to learn more.

Although there might be lots of good things about pumped-storage there's no need to oversell it as a   zero-impact option. In South Africa's case, it's coal electricity sent by AC lines that send the water uphill...

Whiskerfish

Pimp storage is not a bad idea at all.  Not only can it be used to capture power from intermittent sources.  It can be used to store power from conventional generators in off peek hours, and then drawn on during peek demand hours.  There are surely mountain tops in this country that do not constitute unique habitats.

The problem with combining wind and solar power with pump storage is the cost of building, operating and maintaining duplicate (triplicate? quadruplicate?) generating capacity.  Your actual costs for a wind + pump storage system would be the costs of the wind system that meets immediate consumer demand + the cost of the wind system that powers the pumps in the pump storage system + the costs of the pump storage system.  The same cost situation would be involved with flywheels or any other storage scheme.  

A solar electric scheme that used heat storage conceptually would have fewer generators, but it would still require duplicate energy capturing systems.  It strikes me that such a system might hold some long term promise, and should be explored.  But promising is not the same as deliverable.  We need to rely on proven technologies, rather than hoping that an untested scheme will save us.  We should also maintain flexibility, so if we start down one road, and find that another is going to be better, that we posses the ability to switch.

It is by no means clear at present that any alternative energy scheme using existing technology is competitive with nuclear power generation when the costs of reliability is thrown into the cost calculation.      

Charles Barton

Gar, it's good to see that you don't challenge my contention that the last article on pumped storage was based on the sheer nonsense that "Renewables are intermittent".

Quoting me, you wrote :

>Energy storage may, perhaps, assist the commercial viability of intermittent options such as wind and solar, but it is wholly irrelevant to geo-thermal, forest biomass, current turbines, hydro great & small, etc.>

And commented :

>Currently we know how to do sun and wind on a large scale, though one can argue about the economics. No one has demonstrated a commercial current turbine. Undeveloped hydro great and small represents a very tiny potential.  There are strong limits on what we can get from sustainable biomass. Geothermal electricity we can currently tap again represents a very small number, though potential breakthroughs may change this.

As to renewable energy saving a barrel of oil. While the  Alaska wind example I posted about recently, wind electricity is directly placing diesel fuel consumption.<

These comments seem to me a bit hasty and decidedly Yank-o-centric.

In theory we know how to do various energy techs "on a large scale"
but in practice only biomass, followed by mega hydro,
has any significant scale globally.

You seem to be getting different info in the US to what we learn here in UK -
for instance the first commercial Current Turbines are being installed right now in the Bristol Channel.

Sustainable Biomass, like any tech on a finite planet, has limits to it, while it also offers unparralelled ecological, economic and social benefits if well designed.

Geo-thermal has very great potential indeed, given the investment,
while your suggestion that Hydro large & small offer only a tiny potential
utterly wrecks your claims of the easy viability of pumped storage for electricity.

Given that you lack suitable hills, let alone suitable reservoir sites,
across much of the US, just as we do in the rest of the world.
a global reliance on intermittent Wind & Solar backed by pumped storage
would not only require the massive new HVDC grid and steel pylons across the landscapes,
it would also entail vast earthworks to provide the elevated reservoir sites.

All of which seems to me a non starter on any serious scale.

Maybe you could do a couple of trial projects on ideal sites in the Rockies ?

Beside acknowledging that we require energy supplies that offer Power-on-demand,
we also need to recognize that the most intermittent options, being Solar & Wind,
are not only those most easily dominated by the corporations,
they are also the most potent in terms of demanding full-scale conventional back-up supply which, under GW's threat,
is a potent argument for additional nuclear capacity.

It is to be hoped that US activists will be alert to this tactic of the status quo,
and will support the development of those sustainable energies that can offer both local legitimacy and global replicability,
rather than primarily those which the corporations see as profitable.

Regards,

Bill

Specific to the UK area and the US gulf coast

One reliable resource to take advantage of is "Ocean Current Energy"

Runs 24/7

How hard it is to cite pumped hydro (or maybe it was the retrofitting of old)

Either way, one could ask if we have all those  aquifers that we were thinking of plugging up with CO2, couldn't we just plug them up with compressed air instead?

With standard .8 recovery, you can store 420 watts per cubic feet. So it is more like 30 feet of water to manage 6.3 kWh per square foot. Looking at my spread sheet my assumption of head was 875, closer to 900 than 800 feet of head.

Billhook:

Will answer some later. Worldwide hydro potential is low, but that is because hydro needs not only a difference in elevation but a continuous water source -- a river. Modular pumped storage needs only a difference in elevation.  So hydro potential is  not the same as pumped storage potential. So I repeat undeveloped hydro potential is nowhere near current demand. Undeveloped pumped storage could easily meet current demand. As to current turbines: the Bristol example is tidal current, not deep ocean current. Tidal potential is both lower than deep ocean and also less suitable for base load. Similarly, worldwide geothermal potential with today's technology is pretty widely agreed to    to be tiny compared to todays consumption, while under half a percent. The UK is no better off than the U.S. in this respect.  There are maybe two nations in the world where this does not apply. There is some new tech that might change this, but it is not yet mature let alone commerical.

Whiskerfish. I'm pretty sure I did not say "zero" impact. The two examples you mentioned are using natural water courses. I agree we have to be careful where we locate them, but both of these examples sound like conventional pumped storage.

But even done right I'm not claiming it is zero impact. I'm only claiming it is something we can live with, and better than the alternatives. Part of this is the lower impact per reservoir. The other part is the small square footage required. Less than 14-28 square feet per household (not person).

Greyfcln: ocean current turbines have not yet been demonstrated. Tidal turbines have been demonstrated, by nature they are not constant, and anyway there is very limited worldwide potential. In terms of concrete -- Geopolymeric concrete reduces CO2 emissions now, at about double the cost of normal concrete. But the again we are talking about 14-28 square feet for every household in the U.S. (to continue with yank centricism). Even given that dams take a lot concrete per square foot, this is an embedded co2 cost you could get back quickly if it let you (say) replace all existing coal plants with wind plants.

Yes there are other storage means. Let's look at some of them:

Compressed air. Currently all systems that recover compressed air for electricity storage do so by using the compressed air to boost the efficiency of a natural gas turbine. So you continue burning natural gas for power, the efficiency with which you recover power ranges from 50%-65%, and you around half the power produced by the turbines still comes from natural gas. About three to five times as expensive as pumped storage

fly wheels - high efficiency, more expensive than compressed air. Problem, if the power is not tapped quickly it vanishes. Generally you lose all the power in a flywheel in three  to six days.

supercapacitors, batteries, flow batteries and such- very expensive. Also the toxic materials use to create them have their own enviromental costs. Yes some existing batteries are suitable for electric cars and PHEV. But that is because the economics of electric vehicles support higher costs than utilities. For example $350 per kWh of capacity for an auto battery that will last 2000 cycles is a good price for an electric car. For utility power it would multiply your power costs many times. Also a lot of articles about advanced car batteries are based on press releases for batteries not on sale today.

We may expect breakthroughs in such things. Battery prices will come down, maybe very soon. There a great deal of work being done on storing the heat of compression when you compress air, eliminating the need for natural gas as part of the system. But right now modular pumped storage is the most economical and most ecologically sound means to store electricity.

please supply a bit more locational information about the Taum Sauk reservoir.  We shall be passing through the Ozarks this Summer, and may want to stop by for a look.

The park ranger and family pulled out of trees sounds like a scene from a "Fitzcarraldo"-ish vision, if only everyone were unharmed.

Chickens are our cousins! So are other sensitive animals! Enough is enough! No more factory farms!

If you are right I've made a serious mistake. I have the formula right in the spreadsheet. You might want to put in some detail rather than just point in out. This is pretty much physics. No grey area. One of us is right the other is wrong, and if I am the one who is wrong I want to post a correction right away.

OK, I'm way off. I'll recalculate and correct the post. It looks like it would take more like a thousand square miles than 50. But that is still small compared to existing hydroelectric facilities.

Not likely.  MDI, the company behind the hype and the air engine itself, has been claiming they are just a few months away from production since the late 1990s.  As of late April of this year, according to the Swiss guy in Northern California who owns the failing ZevCat franchise, which is relying on the same MDI engine to produce a product, MDI has never been able to produce so much as one prototype that comes close to providing the sort of range they keep telling everyone the car will provide.  Suspiciously, after another round of hype and signing of new contracts (followed by even more hype), MDI admitted their engines did not work, but they completely redesigned them, resulting in exactly the same claims about driving range and cost per mile, even as energy prices had substantially increased.

Meanwhile, Tata, the Indian company is getting bogged down in a nasty turn of human right abuses and even murder as the government with which it is collaborating uses thuggish tactics to clear the way for their new auto factory.  I can just imagine how peaceful and reliable that plant is going to be, even if they ever get an MDI engine that can power an overblown go-cart with a body made out of surfboard materials more than 20 miles.  But that doesn't stop lots of people from reading the failure of journalism published in a recent issue of Popular Science and dreaming of the remarkable air car (even though the article did note that it is unlikely that the car will ever make it to the U.S. for safety reasons alone).  Everyone likes a good story, especially when reality is so much more challenging.

Be careful.  Pumped storage serves many purposes, but I would not characterize it as a renewable play.  Grid consumption peaks in midday, and it is generally easy to find a home for solar at the instantaneous point of generation.  This is also somewhat true for wind, since the wind tends to blow harder as the air heats up.

The pumped storage facilities in operation - and indeed, all storage facilities - exist to take advantage of differential pricing between on-peak and off-peak electricity.  From batteries to reversible fuel cells to pumped hydro, the relevant number for all of them is the "round trip efficiency", which simply measures the total kWh out as compared to the total kWh in.  Apropos of this discussion the relevant point is that the round trip efficiency is always <100% (70 - 80% is fairly typical).

Thus, the economic play is straightforward.  If I have an 80% round trip efficiency, and I can buy off-peak power at <80% of what I can get selling it on-peak, then I can make money arbitraging the differential.  Economically, this can be a good thing, since it lowers the daytime electric rate, putting supply on the grid that is cheaper than that which we otherwise would have had to produce.

As a practical matter, the single biggest beneficiary of pumped storage from a generation perspective though is coal.  Nuclear power is now very close to baseloaded, with most nuke facilities producing full load 24/7.  Hydro also runs as close as it can get to baseloaded (e.g., as long as there's upstream water, it will run), since nothing else is cheaper.  Coal is the next cheapest power source on the dispatch curve, but it curtails production at night for the simple reason that sometimes the total system demand exceeds the total production capacity of the nuclear+hydro+coal resource base.  As the most expensive source on that list (albeit cheaper than the gas-fired generation at the margin), coal is the first to curtail production in the evenings.

So - watch what happens if you start deploying lots of pumped storage on the grid.  More nighttime load = less need to curtail coal = more coal combustion.  As I said, this may well lead to lower power costs in some areas, but it is the exact opposite of a renewable play.