Energy storage, cheap and low tech.

[MossRoad]

I'm sorry, my 30kW quote was from an earlier version of the Prius. Here's the latest version.

I found the article that you pulled that screen shot from...

FD Prius Power

If you read it, and look at the diagram, the owner is only running a 1000W inverter from the 12v battery of the Prius to power a small load, not 50,000W.

 

[SPYDERLK]

The train goes up, the train goes down: a simple new way to store energy - Vox Just run into it. It seems to me that it is doable even on small farm size scale.

So nobody sees anything wrong with the 86% efficiency claim?

 

[MossRoad]

So nobody sees anything wrong with the 86% efficiency claim?

You don't think it's that efficient or you're concerned with a 14% loss?

 

[SPYDERLK]

I found the article that you pulled that screen shot from...

FD Prius Power

If you read it, and look at the diagram, the owner is only running a 1000W inverter from the 12v battery of the Prius to power a small load, not 50,000W.

That does not change the fact that there is net 50KW available from the engine / generator system. Conditioning it for home power is all that remains.

 

[SPYDERLK]

You don't think it's that efficient or you're concerned with a 14% loss?

I doubt the end to end efficiency claim. Im thinking that the losses are actually 14% for both the up conversion and the down conversion. ie, 86% of energy put in is stored at hilltop - and 86% of that can be gotten back. ... ~74% overall

 

[CalG]

Interesting discussion. I don't think I'm going to jump into it, but when discussing this, keep in mind that kW or mW (kilowatts/megawatts) is a measure of power and to compare energy you need to talk about kW-hrs or mW-hrs. If you find something that says 1000 mW of storage, that doesn't mean anything. If it's really 1000 mW-hrs, that means it can provide 100 mW for 10 hours. Articles promoting storage ideas like to give the impression it can back up a plant of a certain capacity when it's really only a fraction of that for an extended period of time.

I thought I had been instructed that a Watt was a unit of power. Just like a gallon is a unit of volume.

And regardless how you slice it, be it a quart a minute for four minutes, or a gallon all at once, the same amount of whatever was being transferred.

So if you have a 1000 milliwatts of energy available, you can take the entire amount in a moment (like discharging a capacitor across low resistance), OR dribble it out at 100mW/hr over 10 hours. It's the same total amount of energy.

So saying you have 1000 mW available describes capacity perfectly, just like a gallon.
Your description is close. 100mW delivered for 10 hours is exactly the same as 1000mW storage available.
I've got a 125 mW memory saving Li-ion battery down on the bench merrily lighting a green LED that draws about 15mW at 3 Volts
The set up is good for a few days, then the battery is drained and needs charging. The numbers work out so long as I apply a fudge factor for the age and condition of the battery. ;-)


Watts are Watts! ;-)

Now energy generation capacity needs to be stated as continuous or peak output, but that's

 

[SPYDERLK]

I thought I had been instructed that a Watt was a unit of power. Just like a gallon is a unit of volume.

And regardless how you slice it, be it a quart a minute for four minutes, or a gallon all at once, the same amount of whatever was being transferred.

So if you have a 1000 milliwatts of energy available, you can take the entire amount in a moment (like discharging a capacitor across low resistance), OR dribble it out at 100mW/hr over 10 hours. It's the same total amount of energy.

So saying you have 1000 mW available describes capacity perfectly, just like a gallon.
Your description is close. 100mW delivered for 10 hours is exactly the same as 1000mW storage available.
I've got a 125 mW memory saving Li-ion battery down on the bench merrily lighting a green LED that draws about 15mW at 3 Volts
The set up is good for a few days, then the battery is drained and needs charging. The numbers work out so long as I apply a fudge factor for the age and condition of the battery. ;-)


Watts are Watts! ;-)

Now energy generation capacity needs to be stated as continuous or peak output, but that's

Power is Energy per unit Time. Watts are Power. Energy is work ... Power multiplied by Time. If you want to do any work it takes time.

,,,,,,,,,Pumping a gallon instantly would require infinite power.

 

[CalG]

rate X time = volume/distance/etc. simple math. It's fun to consider what happens when the denominator is ZERO! ;-)

 

[Redneck in training]

So nobody sees anything wrong with the 86% efficiency claim?

Beats ICE in typical car hands down. Typical ICE in car is not even 20% efficient. Typical refinery requires about 4 to 7.5 kWh of energy to produce 1 gal of fuel. Translated to efficiency, refinery is about 86% efficient. If you consider energy required to produce gasoline or diesel during refining typical car uses about 15% of energy contained in crude oil. In fact it is even lower if you take in into account the energy required to get it out of ground and transport it.
Electric car uses estimated 20-24% of energy contained in the fuel used to generate electric energy. That is almost double of ICE powered car.

Considering the number above, 14% storage loss looks very good especially if the energy is generated from wind or sun. 86% is typical efficiency of small run of the mill electric motor. As the size of the motor increases the efficiency also rises. Large electric motors (MW sizes) have efficiency over 90%.

 

[MossRoad]

That does not change the fact that there is net 50KW available from the engine / generator system. Conditioning it for home power is all that remains.

And no one has done that yet.

And if they do, from some quick web searches, to produce 50KW it has to run at 5000rpm. Typical Prius owners report their engines are running anywhere between 1000 and 2500 RPM at 70 MPH. So 5000 RPM is like running your Prius at 90+ MPH. Who would want their car sitting in their driveway running at 5000rpm for hours or days at a time? Its only got an 11 gallon tank. It would drain it 3-4 times a day and it would be the equivalent of running at 90+ MPH for 24 hours, or about 2000 miles! Who's going to want to put 2000 miles of hard wear and tear on their car each day and suck down 40+ gallons of fuel?