Gravity Battery

In yesterday’s post I mentioned two Israeli companies that allegedly made big breakthroughs with solar power. Many of you noted that solar power is limited if you can’t store the energy in a cost-effective way for night use.

I did some Googling to see what’s new in battery storage, and this potential breakthrough popped up. Obviously it must be viewed skeptically until proven viable.

http://news-service.stanford.edu/news/2008/january9/nanowire-010908.html

But I got to thinking that there must be a more natural way to store energy, using gravity. It might not surprise you to learn that I found exactly this sort of idea, appropriately, in the halfbakery.com web site:

http://www.halfbakery.com/idea/energy_20storage_20gravity

http://www.halfbakery.com/idea/Windmill_20Compressor_20Home_20Energy_20System#1121567081

I know, I know, you will point out that even if such systems of energy storage existed, they would be inefficient. It takes more energy to move a rock up a hill than you can capture from the return.

But how inefficient can your storage device be and still be viable? There is some theoretical amount of cheap energy production that compensates for almost any degree of inefficient storage. So if, for example, solar panels became 1,000 times more efficient and cost you next to nothing, it might not matter if your storage device could only capture half of what you generated. You’d still have plenty to get you through the night and charge your electric car too. I think it’s entirely plausible that we’ll have home battery systems, whether gravity based or not, that make oil obsolete except for specialty situations such as jets and maybe big trucks.

Some of you noted that oil has so much energy for its weight that solar power can never be expected to replace it for cars. But that too is more of a function of battery storage. Perhaps the nanowire battery or something like it will solve that. I think it will happen. And I think Israeli companies will be in the forefront, for national defense reasons, while the United States argues about flag lapel pins.

Comments

[tom]

I realize that this post is dead, But I think that there is a relatively easy fix.
the issue is that a chemical battery (gas, storing chemical potential energy, for example) is better than a physics based battery, which would be subject to friction, etc.

we know that water can be separated into oxygen and hydrogen with electricity

we also know that recombining into water inside a fuel cell yields power (don't know how much, doesn't really matter)

if we have massive solar farms constantly making electricity, then using it to divide water, then we recombine it in car fuel cells, we have a transportible way to store energy, with 0 emissions and minimal toxic waste (only what goes into replacing fuel cells over time)

[Grog]

I want a yabba-dabba-do big gravity battery to mount onto my electric car. I could hook the winding line up to trucks on the interstate, let them pull out ahead of me, and disconnect to get all that recovered potential energy! Yee-haw!

[Bjælkehuse]

Would just say that we value you work I the office-environment in Denmark :-)

[murgadroid]

Hi Scott:
Colorado has had a system like this for years in near Glenwood Springs. During the night when electricity is cheaper, they pump water to a high reservoir. Then during the day when the electricity is more expensive, they run the water back through turbine/generators. Using excess capacity at night is another way to save the energy (in a virtual sense).

[Dan Kennedy]

Pumped hydro storage is in use in the Canary islands.

Wind powered pumped hydro storage systems, a means of increasing the penetration of renewable energy in the Canary Islands, by C. Buenoa and J.A. Carta
linkinghub.elsevier.com/retrieve/pii/S1364032104001285
(disclosure, I work at elsevier)

Also wikipedia has a good page listing known pumped hydro insilations worldwide. http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

[Sam]

Scott

You have stopped being witty. That was the best part of your blog. Lots of people are commentators, but few are witty ones. Sorry, but your blog's sometimes becoming tedious to read!

[Anarchy In Your Head]

If you're on the grid, any energy your solar panels or windmills or whatever produces beyond what you need feeds the grid and reduces the amount of power needed from other sources throughout the day, thereby saving those other forms of energy for nighttime use. If you want to be off the grid, the batteries are an issue, but otherwise solar power or something else is still very useful and storage is not really a problem. The meters of people with solar panels can potentially run backward during the day making up for energy they took form the grid at night. In some places, if you actually produce more than you consume, you get paid something by the power company for that energy.

[Larry S]

A pumping power plant exists in Luxembourg, where off peak electricity from the power grid is used to fill a reservoir. During peak electrical use periods, the water in the reservoir is released to power geneerators. See the following link.

http://www.tourist-info-vianden.lu/english/vianden/seo/index.html

[KickMe]

Yeah, first post is right. It's widely used in Europe, where there's "cheap" energy during the night (nuclear power stations can't be stopped just for the night) and dams with big lakes. Water is pumped up at nighttime and is used to generate power during daytime.

[st512]

I can't believe nobody realy answered your Question yet...

So let's try:

say we need to store 2 kWh, that is 7.2 MJ. If we use a storage height of 5m by average, we need 144 tons of Water.
If the reservoir is 1m deep, that is 12mx12m wich is a pretty big swimming pool...

keep up the nice posts!

[Quartz]

What about maglev highspeed flywheels? Tech is getting better fast, and looks veeery good. Perfect for home, no way to use it in a car though...

[AMusingFool]

I'd like to point out that long-distance travelling via car will also pretty much require a gas tank (unless you can get enough batteries to not have to stop at all). Otherwise, the length of time it takes for the recharge will make gas fairly necessary. (unless you want to envision a multi-hundred amp circuit at the "filling station", I suppose :).

[WCE]

You can store energy very efficiently with a flywheel rotating in a vacuum.

You can get the energy in using a motor, which can have efficiencies approaching 98%, and when driven by the flywheel, become generators, also about 98% efficient.

One thing that flywheels are good at that motors aren't is dumping a lot of horsepower very quickly, through a mechanical transmission/clutch. This makes them ideal for electric cars.

If your commute doesn't involve a lot of hill-climbing (most don't), then you can use the flywheels for regenerative-braking, storing the kinetic energy of the vehicle at-speed in a flywheel whenever you hit a red light. That same kinetic energy will be available when the light turns green, less a tiny loss incurred during the duration of the red light, generally less than a couple minutes.

You only need about 30HP to maintain a midsized car at 60mph, well-within the range of available electric motors.

BTW, this scheme still requires batteries, it just provides V-8 performance for the consumers who don't like taking half a minute to get up to highway speeds.

Aluminum-air and aluminum-H2O2 batteries tend to have about 20x the energy-density of lead-acid batteries, and we already have a robust infrastructure for making metallic aluminum using hydroelectric generators. Refilling at the service station would involve swapping-out spent standardized batteries for fresh ones, with credit given for remaining metallic aluminum in the old ones.

The pumping water uphill as a means of energy-storage idea isn't new, BTW, it was used as an illustration in my Thermodynamics class back in '76. Not as good as one might hope. There are better ways of storing energy.

[tony]

You don't use a battery at home.
You sell your excess to the power company: they either sell it to those that need it at the time, or store it much more efficiently than you can at home in pumped storage: effectively reverse hydroelectric where you use surplus power to pump water uphill to a reservoir, then drain it for power as needed.
We did that in the uk to remove cyclical loading from nuclear plants.

[John]

Why not just have a block of DU that is spun once at a high velocity, give it a small motor just to maintain the velocity for a while, and let it keep going.
Obviously the block would have to be spun again occasionally.
But, then again I wouldn't have a clue about this stuff.

[Lets Go Banners]

Interesting idea. It will all come down to supply and demand. I think Solar is the way to go (isn't it obvious with the sun shining everyday? There HAS to be a way we can tap it efficiently.

[QwkDrw]

Actually, large vehicles may be well able to efficiently carry the heavy weight of electric motors and batteries. Seems logical that SUVs, trucks, busses, etc would be ideal platforms for adapting.

(Can't believe I'm writing another comment to this blog -- it's so time consuming and probably nobody cares ... well briefly, hello enterelligencia.)

Are not diesel/electric locomotives (train engines) basically really big "hybrids"

??
GIVE ME A MOMENT a lifestyle

[chat]

Cool post

[drjon]

Of course, if the solar cells are in orbit with constant exposure, you don't need a damned battery...

[reply http://drjon.livejournal.com/ as I don't wade through the comments here]

[Nicevil]

Space Based Solar Power FTW. :D

http://www.popularmechanics.com/science/air_space/4230315.html

"Ultimately, the report estimates, a single kilometer-wide array could collect enough power in one year to rival the energy locked in the world’s oil reserves.

As envisioned, massive orbiting solar arrays, situated to remain in sunlight nearly continuously, will beam multiple megawatts of energy to Earth via microwave beams. The energy will be transmitted to mesh receivers placed over open farmland and in strategic remote locations, then fed into the nation’s electrical grid. The goal: To provide 10 percent of the United States’ base-load power supply by 2050."

[tom]

"I know, I know, you will point out that even if such systems of energy storage existed, they would be inefficient. It takes more energy to move a rock up a hill than you can capture from the return."

Scott, it is a very basic principle of physics (conservation of energy) that it takes exactly as much energy to move a rock up a hill than you capture as it comes back down. The gravity battery described is probably almost 100% efficient. The problem is that it is inconvenient - requiring a lot of mass and a very strong structure to store any significant amount of energy.

[Gustaf Sjoblom]

I think that you will find that most scientists if given an infinite timescale will agree that solar power will eventually easily handle all our energy needs. However there are huge disagreements as soon as you limit the timescale.

How many major breakthroughs are we looking at? Two? Five? Fifty-seven?

[BoscoH]

[So if, for example, solar panels became 1,000 times more efficient and cost you next to nothing, it might not matter if your storage device could only capture half of what you generated.]

Scott, If my Dad had balls, I wouldn't have been adopted. Solar panels cannot become 1000 times more efficient. They're already within 1/3 of their theoretical limits per square foot. Unless you want an Amazon rain forest of super tall solar trees dangling their solar cell leaves down to the ground and crawling with monkeys and halucinogenic frogs, it ain't gonna happen.

[duh]

Forgot to mention on the EEstor battery claims: Non-toxic and non-explosive.

One more intriguing tech that is available right now is geothermal. From memory, a well is drilled in your backyard to touch earth ~150 feet down where there is a constant 65 degrees F. A pipe circulating water is looped down and back up. Something very similar in size to a standard heat pump is on top and provides a VERY efficient heat exchanger for your AC system. Supposed to pay for itself in a couple of years.

Given that the geo-based temperature differential is available to just about everyone, everywhere, it seems like a Stirling Engine could generate energy from that. Or, maybe this: the inventor of the Super-Soaker has developed a heat-difference *closed system* engine that has claimed 60% efficiency. Now as it turns out that inventor is a nuclear engineer who used to work for JPL until his Super Soaker made him so very rich...

http://www.popularmechanics.com/science/earth/4243793.html

[duh]

Lockheed Martin just signed an agreement in January with EESTOR, a company that claims to be **commercially producing** (in 2008) a battery with 10X the energy density of lead-acid at 1/10th the weight and volume and costing half as much per stored watt-hour. With virtually unlimited charging/recharging. And charge time limited mainly by the electrical system delivering the charge (as quick as 5 minutes). Canadian car-maker Zenn is an investor (http://crave.cnet.com/8301-1_105-9908050-1.html)
Sure sounds good.

http://en.wikipedia.org/wiki/EEstor

[Joseph Hamala]

I just recently took a tour of a Pumped Storage Facility and blogged about it, if anyone is interested. Plenty of pictures.

http://www.unproductivitydefined.com/2008/05/take-this-lithium-ion.html

[TallDave]

Some of you noted that oil has so much energy for its weight that solar power can never be expected to replace it for cars. But that too is more of a function of battery storage. Perhaps the nanowire battery or something like it will solve that.

No, it won't, unless you plan to drive your solar panel - nanowire car for a maximum of about ten minutes a day. There just isn't enough power there; it's off by orders of magnitude.

OK, so maybe you put the solar panels on your house and the battery in your car. Bettter, but...

Batteries are also not good in consumer mobile applications for several reasons. The main one is, again, energy/mass, but there are others even if that is solved, including a tradeoff between recharge time and safety (if you think gasoline is hazardous, imagine plugging a 100-amp cord into your car in the rain), poor performance in extreme heat/cold, and continuous operation ability (an internal combustion engine can be driven continuously, more or less; a battery needs to recharge). Any battery tech that is safe is going to have slow discharge/recharge, and any battery tech that has fast d/r is going to have safety issues.

And don't even think about trying to fly planes with batteries.

The internal combustion engine is not going away.

[L2H]

Most modern damn power stations are able to pump water back up the same pipes the water comes down by running the turbine generators in reverse as electric motors.
At the Castaic plant north of LA (near 6-flags) they have large pipes coming down from Pyramid lake. Then the water collects in a small lake (Blueberry?) which keeps Castaic from rising and falling everyday (bad for fish hatching).
Late at night very cheap off-off-peak electricity from the Northwest (many damns running all night on too much water) is used to pump water uphill, and then the water comes back down during the day when demand is high.
Water here (all of the Southwest) is worth almost as much as electricity, so it makes sense to reuse it as much as possible.

[Mike]

You use Solar to convert water into Hydrogen & Oxygen,which you store, then at night you use a fuel cell to convert them back to water. yes it is less efficient than a battery but when the source is free and a roof sized solar array can produce more Hydrogen & Oxygen than you need then it doesn't matter. If you have a Hydrogen fuel cell car as well then you have your filling station.

[jerry w.]

When politicians don't have their heads stuck where "the sun doesn't shine",

and they aren't sucking up bucks from the energy companies,

then and only then will energy issues be dealt with.

Crap, like that's ever going to happen.

http://boskolives.wordpress.com/

[$8]

I'd store the energy overnight by using it to heat a pool of liquid sodium during the day. The liquid sodium can store enormous amounts of energy, particularly at it's vaporization temperature.

You can then tap this heat to create steam for a traditional steam turbine driven electrical generator.

There are a few companies actually working on this at the moment.

[Casper]

Cool post

[Jason]

It seems that maybe a better force to store energy is heat energy into mass. Only probably is it contantly radiates back out. Could work though for overnight funcation, such as a heating system and lights at night.

[steve]

What if you put giant mirrors in space to collect and concentrate solar energy?

You could direct this energy anywhere on earth. Say somewhere in the American southwest? You would be able to collect energy 24/7.

Then there are ways to store energy as heat on cloudy days.

[Kevin Ballard]

There's a water-powered power plant somewhere (I don't remember where) that's effectively gravity storage. During the day, they let water run down-hill and power their plant. At night, when the energy is cheaper, they buy energy from other plants and pump all the water back up-hill again. I visited it once, it was pretty cool.

[Ace]

I now (and still) believe electric cars might be the way to go. Battery technology has improved over the 10 years that they were absent to the point that electric sedans and gas powered sedans are equal in range and acceleration curve (but the electric cars still don't go as fast, around 65 mph). still solar panels on cars seems kind of pointless. it would be nice if we could get the electric cars to have a faster speed with the similar range.

[Peter Drier]

There's a power plant in NY that already stores energy..

http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

Basically pumping backwards at night when power is cheap, and running normally during the day when more load is necessary.

[mjohnson]

Pump Storqage Power Stations - this one in Wales store an enormous amount of kinetic energy. It pumps it up to the top resovior in the night and lets it out at peak demand. For every unit generated 3 are required. Not bad. You'd loose one quarter of the power:

http://www.fhc.co.uk/ffestiniog.htm

[GLK]

Any fan of DaVinci knows a flywheel is a more elegant solution for making and storing energy than an ascending and descending block. But when it comes to creating NEW energy you cannot defeat the second law of thermodynamics which states in essence that...

2. You cannot break even (you cannot return to the same energy state, because there is always an increase in disorder; entropy always increases).

In other words you cannot get equal or more energy out of something than you put into it. If that was possible perpetual motion machines would be everywhere by now.

OK, so what if energy creation was grossly inefficient yet cheap enough that nobody cares? Well, you still have to deplete something to create that energy. So that "something" would have to be pretty plentiful and inexpensive. And, depletion usually creates unwanted byproducts that have to dealt with.

There are some BMWs running around in Europe that are powered by Hydrogen and there have been pictures published of automated Hydrogen filling stations. As long as you can put the Hindenburg disaster out of your mind Hydrogen makes sense as a fuel because the main byproduct coming out of your exhaust pipe is water vapor.

I guess I'd rather have a zillion cars raising the relative humidity than destroying the ozone layer.

[rita mae]

Hey! I'm retiring in 20 days (not that I'm counting) so I will just buy extra blankets and hole up with the ex-Marine to keep warm. (I said "hole up" BWAHAHAHAHA)

I only want to text about things that make me laugh and don't make me think. Your energy consumption obsession is making what's left of my brain ache. So I will close with............

Please say "Hi" to me once before I retire and leave your site behind in the dust.

Rita Mae

[freebert]

Use solar power to break water into hydrogen and oxygen, then store the hydrogen in tanks to power home hydrogen fuel cells to make electricity when you need it. The hydrogen fuel cell recombines the hydrogen with oxygen in the atmosphere to make pure water. You can even use sea water or other nonpotable water (gray waste water from your shower, dishwasher etc.)- and make drinking water which everyone says we are going to run out of even before we run out of oil. Also,quit trying to put fuel cells in cars - it's stupid, use them where they make sense.

[Julián Rodriguez Orihuela]

Hey! Electrolysis is your friend! Saving it as hydrogen (i think) was one of the solutions that didn't waste so much...

[spoilsport engineer]

There is no "solution" to the energy crisis. There are hundreds of partial solutions. The whole solution consists of doing *all* of these partial solutions.

A hundred years from now we'll have mag-lev trains instead of airplanes, because mag-lev uses less energy. All our roofs will have solar panels, because sunlight is free. We'll have wind farms every windy place. And we'll still be burning oil if it hasn't run out, because cars with solar panels are too big and flat and silly-looking.

We'll still have to wait in line to be x-rayed for the mag-lev. Our roofs will still leak. And we still won't be able to find parking.

The world will change, and it will stay the same. It's comforting.

[drawn asunder]

Isn't that what dams and water towers do? Store potential energy, to be recovered later as kinetic energy during downhill flow?

[FMS]

Now if we could just find a way to generate energy with flag lapel pins...

[Bloodboiler]

The problem with gravity battery is not how much energy is needed to load it. The problem is how impractically huge it need to be to store even small amount of energy.

Energy that you can store by lifting something is mass x height x gravity, where gravity is practically constant that is about 9.81 m/s^2.

Quick googling tells me that average home electricity use by person in US is 5.7 kWh/day. If we assume that solar energy can be used for most of that because we use less electricity while sleeping, that leaves e.g., need for 2 kWh battery. To make that battery we could make a system that lifts a 1900 kg SUV to the roof of the Empire State Building. And that's with perfect efficiency and just for one person's energy needs for one night. Then the solar energy system would have to use at least the same amount of energy to load the system for the next night.

Not too long ago a scientifically clueless designer gave up a green gadget prize he won for designing an utterly impossible gravity powered lamp. So you are not the only one who's ideas get ripped apart on the Internet.

[dan]

chromepoet posted asking if collecting solar energy would reduce warming of the planet.

No, it will not have any effect.

We won't be collecting enough energy to make a difference, and even if we did, as we store/use/transmit energy most of it ends up being converted to heat.

Cole Brodine, nice post.

[Chris Tann, LAWNMOWER MAN]

In Scotland, there is a huge "power storage" device based on just such a principal. They have a reservoir at the top of a hill, and another at the bottom. The two are connected by a huge pipe, with "reversible" pumps in it. When they apply electricity to the pumps (during the off-peak times), they pump water into the upper reservoir. When they need to meet more peak demand, they reverse the flow, and the pumps become generators. I visited the plant, and one of my questions was the efficiency. I don't remember the number, but it was obviously efficient enough to warrant building this huge installation. That was back in the early 90's, not sure if it is still in commision...

Chris.

[HALiverpool]

Hi Scott,

I was thinking yesterday that instead of direct conversion to electricity, one could use stirling engines driven by sunlight like you have mentioned before in your blog. When the sun isn't shining, like at night, the engines could be powered by stored heat in hot water tanks. The tanks could be heated by excess sun power on extra sunny days or by any other heat source, burning garbage...etc.

-HAL

[Into my Timecube!]

Why not use solar power to turn water into steam, which is hot and rises, and then the hot steam goes up to the top of a column where it gets cooled and turns back into water? That'd be an efficient way to run a gravity battery.

I'll gladly let someone use my idea for a 1%-of-net royalty. Contact me. If you don't, consider your butt sued.

[Jim]

Pumped storage has pretty much exactly the same issues as hydroelectric; the facilities required are huge, and vastly eco-unfriendly. Most of all, you have to have exactly the right geography to implement it. Much like standard dams, where it can be used it has.
Batteries are years away from being any kind of useful for high energy applications; low energy density, short life, hazardous chemicals...
I'm kind of scratching my head that only one person here mentioned hydrogen. Electricity (from solar, wind, hydro, nuclear, etc) + Water = hydrogen
Hydrogen can be combusted in a thermal cycle engine or recombined in a fuel cell for electricity on demand.

[Mark Thorson]

There's lots of those pump/
generator systems throughout
the world. They're called
pumped-storage plants.

http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

They could be used to power
cars if we retrofitted all of
the roads with power rails
and replaced our cars with
something like slot cars.

That solves the battery
problem for the all-electric
vehicle. In fact, the cars
would be very green because
they wouldn't be carrying the
weight of batteries or a fuel
tank.

They could be run on low
voltage, so people wouldn't
be fried if they stepped on
the rails. And microcomputer
chips could record who used
how much electricity for
billing purposes.

The cops could have the only
vehicles that used gas, and
control over the switch for
the power rails, so they
could chase down and catch
O.J. Simpson if he kills
any more blondes.

[rebel]

Ah, but what if the flag lapel pin is a solar collector? Huh, ever thought of that? That is why we need our politicians absolutely covered in flag lapel pins; to keep the government working at night!

[Matt]

Yeah, water's probably the better way to go, just because it's more stable and your machinery only has to process a little at a time, instead of lifting a giant block up and down. If the cable on your block snaps, then you get the kinetic equivalent of a short circuit -- a mini-earthquake and your energy for the day gone.

[Kent McManigal]

I have always envisioned some kind of an "energy sponge" that absorbs all types of energy from the environment and converts it into useable form. Think "solar panels" that collect all spectra of EM radiation, even in the "dark".

[Ascii King]

There was an interesting suggestion for improvement to the system on the forum you linked to. Instead of using a concrete block, use a large magnet and when you drop it through a coil of wire to generate additional electricity.

[Dave Wheeler]

What if you looked at it from a global perspective...
If all solar cells were tied into the global power grid, then that would mean the sun would always be shining! The parts of the world that are dark could "borrow" energy from the parts in the sun and "pay them back" the next day with excess production!

Yeah, I know... unrealistic politically, but perhaps we need a global solar power organization to make it happen.

Just a thought,

Wheels

[dan]

If energy becomes cheap, we will just use more of it. All your solar energy will get used during the day, then coal will be burned all night.

When the price of oil starts to really spike (like $300 per barrel) people will buy electric cars and companies will scramble to build/sell solar panels and windmills. Governments will scramble to build nuclear power plants as fast as they can driving the price of uranium up as well.

Only when we start to seriously realize the earth has limited natural resources (prices soar because they are noticeably depleted) will batteries be produced en-mass for grid power storage of solar/wind power.

Batteries in general are expensive and inefficient, and the amount of power that needs to be stored is huge.

It is WAY more efficient to have everyone travel on mass transit using solar power as its collected, then to have people store the power and put it into their cars overnight.

If we don't prepare enough, when the shit hits the fan I expect high-speed electric subway type trains will simple take over the roadways. It won't be worth building expensive tunnels to save the roads when hardly anyone can afford to drive anyways.

If you think we will have cheap solar panels, batteries and electric cars all ready when fuel resource prices spike, you obviously haven't met all the people who cannot afford to drive/own cars already.

The earths population is massive, increasing and probably unsustainable. Food prices have already started rising. Everyone still has their heads in the sand.

[Cole Brodine]

The Hydroelectric gravity system that others have mentioned here is a well established way of saving electricity that is usually generated during the night for much less cost and then reused during the day. As a good economist, I'm sure Scott notes that the huge loss in effiency is made up for by the greatly increased price of electricity during the day.

Excel Energy is working on a really neat energy storage system that I saw a presentation on (I am an Electrical Engineering work for a power utility). They use Wind Power to generate electricty on the grid when they need it, and when they don't they use the same wind power to create Hydrogen. They then save the hydrogen and burn it in large generators when electricity is needed and the wind isn't blowing. It's a completely "green" way of storing energy, since the hydrogen is made from Water and when it is "burned" in the fuel cell the only output is water. This system could easily be applied to Solar Power also.

For now, I don't think you'll have to worry near as much about storing Solar power for use during the night. The largest amount of electricty usage is during the days, especially when it is hot. That also happens to be the best time for Solar to generate. During the night, we have plenty of "base load" from existing Nuclear Plants or Hydro Plants (And low cost Coal plants too, but I think the focus here is on "Green" generation). The wind also tends to blow quite a bit more during the night, so wind power is more viable then too.

I believe that the solution won't be in one kind of renewable energy generation, but in a large mix of them. That will be better anyway, since it will help diversify your generation portfolio and prevent large rises and falls in they amount of electricity generated (thereby creating much less need for storage)

[One of the many Josh's on here]

This has been done at the Raccoon Mountain Pumped-Storage Plant outside Chattanooga. They fill up the mountain-top lake from the river during low-energy-usage times, and then drain the lake to generate at peak times, selling the energy back to the grid.

http://www.tva.gov/sites/raccoonmt.htm

[dsg]

Hi Scott,

It is good you expanded your discussion of how solar power will greatly reduce oil usage. From yesterday's posts lots of people missed the step that this amount of cheap electric power will make electric cars much more popular. With better batteries that will push oil off even more.

I do believe that the world is so dependant on oil that it will never go away. My gas powered boats will last a long time, and I will never go into blue water on electric alone. My cars will also last a long time. Some people will adopt new electric technology driving down oil prices and pollution and the rest will be happy with our old stuff at cheaper prices. The market will balance between the old and new. And, as you pointed out before, oil is fungible and will always be bought from the cheapest source, the middle east will still do well.

Thanks for the post,
dsg

[Andrew]

Batteries like we put in our walkman...wait we don't use those any more...I mean batteries that we put in our kids' toys take more energy to produce as compared to the amount they hold. not to mention the waste when we toss them in the trash...

So we are already used to a system that is inefficient...
I don't see why inefficiency should be an issue, I am suprised that Wally hadn't thought of it....oh...that is right, he is the most cost efficient employee according to today's vid.

[dan]

Make some hydrogen by day, burn it in your fuel cells by night?

[Chromepoet]

While reading this post and comments I got to thinking to myself, for no apparent reason, what if:

What if we did create and begin to use many extremely efficient solar electric sites. Would collecting and storing significant amounts of solar energy stop global warming by taming the Sunrays before they chaotically whirl, twirl, and sing our dirt and air to an excited state of over-heated?

[DF]

Hopefully the solar technology will take off, and the batteries will improve, to the point where they are cheap and viable for everyone. Houses powered off a solar power and wind power grid, or individuals with their own solar/wind combo. Cars that they plug in every night, with better batteries so they can last longer with no memory problems. With cheap energy, you could switch mass transit to run off the electrical grid, swap buses for trams and subways. Until such point that the batteries are able to power buses and transport trucks for long distances. I don't forsee a time when the batteries would be efficent enough to power jets and cargo ships on ocean bound trips, but I hope I am wrong.

Gee Scott, now that you are saving the environment and solving the world's crisis, why don't you blog about banning tobacco/cigarettes to save the health of Americans. After all, if the big oil companies and religious groups aren't already trying to find a way to kill you and make it look like an accident, you might as well encourage the tobacco companies to help them brainstorm.

[Mr. Wampus]

Regarding using compressed air as an energy source, there are several car companies with plans to make cars that run on compressed air and at least one company, Tata Motors in India plans to release a commercial vehicle sometime this year.

Here's a link with some info.
http://www.businessweek.com/autos/content/mar2007/bw20070319_949435.htm?campaign_id=rss_topDiscussed

[Andrew]

Exactly this idea is used in Real Life already:

http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

Any form of potential energy will work; none is 100% efficient. Gravity's as good as any, though not very portable. That doesn't matter for home/national grid use.

[dan]

Part of the problem with that is to capture any significant amount of energy you have to move something up very high, which takes a big ugly tower or a mountain or something like that that you may not have on hand.

You can do the same sort of thing more in more space friendly ways, like winding up a spiral spring. Or spinning up a flywheel. As a group, these could be called Kinetic batteries.

[dan]

Part of the problem with that is to capture any sigifigant amount of energy you have to move something up very high, which takes a big ugly tower or a mountan or something like that that you may not have on hand.

You can do the same sort of thing more in more space friendly ways, like winding up a spiral spring. Or spinning up a flywheel. As a group, these could be called Kinetic batteries.

[Peter]

Aren't there people working right now on creating artificial crude oil and/or gasoline? Seems like that is the most practical. Instead of waiting for nature to take solar power and convert it over time to fossil fuels, find a way to take that same power and catalyze the process.

[Roger]

So maybe the answer is not to be a greedy self and share the electrisity generated by your solar panels with the bloke next door, and if he shares it with the next bloke and so on and so forth, and you take the idea to an international level, then hey its always sunny somewhere in the world.

[JimG]

There are many other ways to store kinetic energy - for example, a spring. Much work has been done on gas or hydraulic accumulators - again, same principle. At least for moving storage devices, the advantage of any of these alternatives vs. gravity is that gravity relies on mass: the more the mass, the more energy stored - however, then more energy is required to move it horizontally as well/

[Craig]

One way to use gravity to store energy is to pump water up to an upper reservoir (from a lower one) and then run it through the dam's turbines when you need it. Sound stupid? Its how they store the power from the Oconee nuclear plant in SC. I had to admit that I became a bit disappointed to learn that the nuclear reactor I lived next to was, in some sense, just a battery.

[Chris Foulkes]

Pumped-storage hydroelectricity is where it's all at...

[Ian Edwards]

There is a power station at Ben Cruacchen (spelling?) in Scotland that buys cheap electricity at off-peak times. They use the electricity to pump water up into a lake at the top of the mountain, and then release it during peak times when the electricity is worth more. The tour guide says it stores enough to boil every tea kettle in Scotland at once, and the station is kept in standby for half-time during big soccer games when there will be a spike in tea kettle use.

[fatcatfan]

It's standard engineering practice to pump water into reservoirs as "battery" storage of hydroelectric power. That's basically using gravity. It's as efficient as your pumps and turbines, which have the benefit of many years of refinement. However, I wonder if there isn't some sort of capillary action system which could be used to "pump" water to a reservoir without inputting energy from the grid?

Still, that's bound to be far less efficient than storing electricity directly from a solar cell to a nanowire battery.

[Popster]

I found a link to the reversible dam I mentioned in my previous post.

http://www.asme.org/Communities/History/Landmarks/Hiwassee_Dam_Unit_2.cfm

Doing the gravity idea in an individual backyard does not seem practical. Now a neighborhood power storage system...

[Real Live Girl]

And hopefully, Mr. Burn's isn't planning on buying the sun or blocking it. LOL.

[jerry w.]

What if we could use solar power to move a rock up a hill, and then drop said rock

on the head of anyone that refused to give up driving their hummer?

Note, not on the head of anyone getting a hummer.

Nor, on anyone that's giving a hummer.

http://boskolives.wordpress.com/

[Popster]

This has been done, kinda. There is (at least there was) a dam somewhere that generates hydro power during the day. At night when energy is cheaper, the generators become motors and the turbines become pumps, lifting water back into the reservoir to reuse the next day.