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

[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.