Energy storage, cheap and low tech.

[KennyG]

The 86% may be overall. Optimized high voltage motors and generators should be close to 95%. That would give you about 90% on the motor/generator cycles.

 

[SPYDERLK]

I think the way to look at it is getting 74% OF your money back, not 74% Interest ON your money.

Then theres startup and overhead.

The 86% may be overall. Optimized high voltage motors and generators should be close to 95%. That would give you about 90% on the motor/generator cycles.

Yes, possible for the barebones. But the losses from transmission gearing, rolling, air resistance all add up too. With all the money to set up and run and maintain it will have to be very efficient to be viable. ... And making it more efficient just costs more.

 

[Redneck in training]

Then theres startup and overhead.

Yes, possible for the barebones. But the losses from transmission gearing, rolling, air resistance all add up too. With all the money to set up and run and maintain it will have to be very efficient to be viable. ... And making it more efficient just costs more.

Gear loses are generally low. Less than 4% on high speed and way less on slow turning machines. (In example AWD cars have about 3-4% greater fuel consumption.) Air drag is not significant at the speeds the cars are moving and since it rides on metal wheels the rolling resistance is also low. I also think that maintenance expenses will be low. Less than railroad cars and tracks because of low speed. Therefore I think that the 87% efficiency is about right.

 

[MossRoad]

I don't know if I'll ever own one, but did you know that a Prius or any other hybrid can be used as a standby generator for your house with a simple kit?

Prius has a 30kW generator.

The better ones start and stop the engine as needed to maintain the charge. Quiet too!

I respect your opinion and many informative posts, but several things need to be corrected.

First - I never mentioned a "kit" in my posts. You must be confusing me with other posts.

Second - I don't know where you got your information that the Prius needed to run at 5,000 RPM to produce it's maximum output. Here is a chart for the early version of the Prius (30kW) that clearly indicates that the maximum output occurs between 940 and 2,000 RPM, significantly lower RPM than a typical generator. In fact at 5,000 RPM the output drops off.

Well, your first post mentions a simple kit and implies that you can make a 30,000W generator to run a house with a simple kit.

That graphic you show for the 30,000w Prius is the 2000 RPMs of the generator to produce 30,000W. How many RPMs does the gas engine have to turn to produce that much power??? 5000 RPMS. Here's the source.
Prius Specifications

 

[buickanddeere]

The 86% may be overall. Optimized high voltage motors and generators should be close to 95%. That would give you about 90% on the motor/generator cycles.

There is no way possible to achieve that kind of electrical and mechanical efficiency. 75% overall would be real world.
Have the proponents of this loaded rail storage system provided actual numbers of the Kw/hr storage and the cost per KW/hr ? How many thousands of these trains per state would be required.How many US mountain sides are available ? What about all the screaming environmentalists ?
A sodium battery system would be more viable.

 

[KennyG]

There is no way possible to achieve that kind of electrical and mechanical efficiency. 75% overall would be real world.

When we specify motors, we require over 92% for even small motors. If I recall correctly, the current US standard for large motors is either 95% or 96%. As was noted earlier, slow moving trains could be low friction loss. Again, I think the efficiency is achievable, I just wonder how the capital and operating cost would net out compared to other options.

 

[orezok]

That graphic you show for the 30,000w Prius is the 2000 RPMs of the generator to produce 30,000W. How many RPMs does the gas engine have to turn to produce that much power??? 5000 RPMS. Here's the source.
Prius Specifications

Let me enlighten you as to how a hybrid vehicle works. The electrical motor/generator provides virtually all of the torque up to a speed of about 45 MPH. With typical driving that would be at less than the 2,000 RPM where the peak electrical energy is produced. Above 45 MPH the gas engine increasingly takes over and the electrical side starts to drop off as the graph indicates. Yes, the gas engine will reach 5,000 RPM eventually as you accelerate to a speed above 45, but it is not necessary for the engine to run at that speed to produce it's maximum electrical output.

 

[SPYDERLK]

Let me enlighten you as to how a hybrid vehicle works. The electrical motor/generator provides virtually all of the torque up to a speed of about 45 MPH. With typical driving that would be at less than the 2,000 RPM where the peak electrical energy is produced. Above 45 MPH the gas engine increasingly takes over and the electrical side starts to drop off as the graph indicates. Yes, the gas engine will reach 5,000 RPM eventually as you accelerate to a speed above 45, but it is not necessary for the engine to run at that speed to produce it's maximum electrical output.

The unavoidable question is how more power can be derived at a given rpm than the engine can produce. Leave stored power out to avoid confusion.

 

[SPYDERLK]

Gear loses are generally low. Less than 4% on high speed and way less on slow turning machines. (In example AWD cars have about 3-4% greater fuel consumption.) Air drag is not significant at the speeds the cars are moving and since it rides on metal wheels the rolling resistance is also low. I also think that maintenance expenses will be low. Less than railroad cars and tracks because of low speed. Therefore I think that the 87% efficiency is about right.

If it is 86% overall
,,,,,I believe it is a theoretical maximum using conventional technology. This would be using ALL optimization short of; superconducting power components and non contact bearings and totally rigid track support with tracks and wheels made of tungsten carbide or harder to minimize hysteresis.

 

[orezok]

The unavoidable question is how more power can be derived at a given rpm than the engine can produce. Leave stored power out to avoid confusion.

Thats EXACTLY why they have batteries. The batteries provide additional power above the output capacity of the motor/generator at any given RPM. The motor/generator then replenishes the batteries when possible. When the vehicle reaches the maximum COMBINED output of the motor/generator and batteries, the gas motor directly provides the additional horsepower.

There is no confusion about the combination of motor/generator and batteries in a hybrid. They HAVE to work together unless you are talking about something like diesel/electric locomotives which relies only on the generator.

 

[Redneck in training]

The idea of low fuel consumption of hybrid cars is based (beside regenerative braking, reduced aerodynamic drag etc) on optimization of the engine operation. The control system keeps the operation at the point of the lowest specific fuel consumption as much as possible.

 

[dickfoster]

The idea of low fuel consumption of hybrid cars is based (beside regenerative braking, reduced aerodynamic drag etc) on optimization of the engine operation. The control system keeps the operation at the point of the lowest specific fuel consumption as much as possible.

Regen braking is great as long as you're in the city and stop and go traffic but once out on the highway and the open road you're dragging along a lot of extra weight that is not doing anything for ya. You need to factor in conversion loss into all equations concerning fuel used and useful work accomplished along with any transmission loss. If you don't you're just kidding yourself. Every time you convert energy from one form to another you're losing something in the conversion, chemical to electrical back to mechanical etc. etc. That's way motors etc. get warm or hot or even batteries when they are being charged and the chargers used to charge them. That heat is wasted energy as is the heat going out of an exhaust pipe or being wasted in an engine's cooling system or up a smoke stack at a power plant. Modern automotive gasoline engines are about as efficient as a modern fossil fueled power plants but once you add in conversion and transmission losses you're working on the losing side of the equation not to mention the work required to haul the weight of batteries etc. That's way electric cars are so silly in environmental terms. Most of em are actually burning coal and doing a bad job of it.
It's simple physics and mother nature. In physics you learn that nothing is free while everyone should know by now that you can't fool mother nature and get away with it.

 

[SPYDERLK]

Let me enlighten you as to how a hybrid vehicle works. The electrical motor/generator provides virtually all of the torque up to a speed of about 45 MPH. With typical driving that would be at less than the 2,000 RPM where the peak electrical energy is produced. Above 45 MPH the gas engine increasingly takes over and the electrical side starts to drop off as the graph indicates. Yes, the gas engine will reach 5,000 RPM eventually as you accelerate to a speed above 45, but it is not necessary for the engine to run at that speed to produce it's maximum electrical output.

WRONG. 50 KW Prius : 76HP X 746W/HP = 56.7KW Engine power. Youre going to have to use every bit of that to get 50KW electrical output. It would take a 76HP tractor engine to produce that at 2000rpm.

The unavoidable question is how more power can be derived at a given rpm than the engine can produce. Leave stored power out to avoid confusion.

Thats EXACTLY why they have batteries. The batteries provide additional power above the output capacity of the motor/generator at any given RPM. The motor/generator then replenishes the batteries when possible. When the vehicle reaches the maximum COMBINED output of the motor/generator and batteries, the gas motor directly provides the additional horsepower.

There is no confusion about the combination of motor/generator and batteries in a hybrid. They HAVE to work together unless you are talking about something like diesel/electric locomotives which relies only on the generator.

Werent we talking about the amount of power available from a Prius platform in connection a home generator adaptation,? ... No real reason to deal with the stored energy capability. It will improve the system efficiency/suitability, but the contention in the thread seemed to be that house supply would stress the platform. BS since no house uses 50KW long term, and stored energy could supply short term ride thru above that.

...If you want to talk with stored energy included we must get a little more rigorous. While the max continuous Power can be known by Engine HP and generator capacity and efficiency, the max short term power is not established w/o knowing how fast the stored energy can be pulled from the battery. This energy rate ...[Power], then added to the max continuous power will give the highest KW ride thru of a fairly short duration event.

 

[KennyG]

Regen braking is great as long as you're in the city and stop and go traffic but once out on the highway and the open road you're dragging along a lot of extra weight that is not doing anything for ya. .... Modern automotive gasoline engines are about as efficient as a modern fossil fueled power plants but once you add in conversion and transmission losses you're working on the losing side of the equation not to mention the work required to haul the weight of batteries etc. .....

Hybrid cars get the greatest advantage around town, but they also do better on the highway. This is because they are able to use an Atkinson or similar cycle which is more efficient but loses low speed torque. Some non-hybrid cars are now getting some of this advantage through variable cam timing but the hybrids utilize it better.

Supercritical coal plants have well over 40% thermal efficiency and combined cycle gas plants can top 60%. Modern automotive engines can get into the mid-30s but that's only a peak efficiency. Most of the time they have lower efficiency while the generating plants operate at constant high efficiency. Electric cars do net out on energy consumed but not on CO2 if coal is the source since coal is much more CO2 intensive than gasoline or natural gas.

 

[orezok]

WRONG. 50 KW Prius : 76HP X 746W/HP = 56.7KW Engine power. Youre going to have to use every bit of that to get 50KW electrical output. It would take a 76HP tractor engine to produce that at 2000rpm.

I think we are mostly on the same page when talking about the output of the hybrid vehicle. Using your formula in reverse while ignoring losses, 50,000 / 746 = 67 HP. Is there some reason that you believe that the 134 HP Prius engine can't develop 67 HP at 2,000 RPM? Thats 50% of its maximum gas engine output.

In reality, you would only need 10 to 15 kW to backup power a house. That's probably less than 20 HP.

 

[Redneck in training]

Regen braking is great as long as you're in the city and stop and go traffic but once out on the highway and the open road you're dragging along a lot of extra weight that is not doing anything for ya. You need to factor in conversion loss into all equations concerning fuel used and useful work accomplished along with any transmission loss. If you don't you're just kidding yourself. Every time you convert energy from one form to another you're losing something in the conversion, chemical to electrical back to mechanical etc. etc. That's way motors etc. get warm or hot or even batteries when they are being charged and the chargers used to charge them. That heat is wasted energy as is the heat going out of an exhaust pipe or being wasted in an engine's cooling system or up a smoke stack at a power plant. Modern automotive gasoline engines are about as efficient as a modern fossil fueled power plants but once you add in conversion and transmission losses you're working on the losing side of the equation not to mention the work required to haul the weight of batteries etc. That's way electric cars are so silly in environmental terms. Most of em are actually burning coal and doing a bad job of it.
It's simple physics and mother nature. In physics you learn that nothing is free while everyone should know by now that you can't fool mother nature and get away with it.

The fact is that hybrids do about 55 mpg while similar non hybrid car would be hard pushed to do 30 mpg.

 

[dickfoster]

The fact is that hybrids do about 55 mpg while similar non hybrid car would be hard pushed to do 30 mpg.

As long as they don't get in my way doing it. Those things can't pull a sick ***** out of bed.
BTW I don't think you'll ever make it to redneck status. LOL

 

[orezok]

As long as they don't get in my way doing it. Those things can't pull a sick ***** out of bed.
BTW I don't think you'll ever make it to redneck status. LOL

Better not get in the way of a Tesla.

 

[Redneck in training]

As long as they don't get in my way doing it. Those things can't pull a sick ***** out of bed.
BTW I don't think you'll ever make it to redneck status. LOL

Yes, I do great bonfires but beyond that my redneck conversion is total failure.

 

[KennyG]

As long as they don't get in my way doing it. Those things can't pull a sick ***** out of bed.
BTW I don't think you'll ever make it to redneck status. LOL

I think maybe you are talking about the Prius but there are other hybrids out there. I have an Escape hybrid and a Fusion hybrid. They both have more horsepower than the base engine model and less than the high horsepower optional engine in the gas only versions. Of course, I'm one of those people who don't usually get in a hurry, so I'd probably annoy you in my truck or one of my other cars, as well as the hybrids.