Smart Grid

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Smart Grids (SG) are gaining popularity around the world:

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

I would like to know your opinion about their current/future effects on our lives.

SG is a wide term, and I would like the discussion to focus on the end-customer experience.
Smart Energy Meters included.

Some related local links:
https://www.avrfreaks.net/index.p...
https://www.avrfreaks.net/index.p...

No RSTDISBL, no fun!

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About 35 years ago I was a planning engineer working for a utility. At that time operations were done by smart people, with experience that worked with neighbor utilities for power exchange. I often did load flow programs to simulate the system and stability studies to insure exchanges were possible.

It seems without careful design the result could be much like computer trading on the stock market. Enron.

I also have designed very successful power meters. That is all in the past. I think more about living in the woods, using a camp fire. I think the American Indians had it figured out.

It all starts with a mental vision.

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KitCarlson wrote:
At that time operations were done by smart people, with experience that worked with neighbor utilities for power exchange.

I was working at one of the biggest power stations in Poland some time ago. These power exchanges were made by operators via phone calls, at about 15 minutes intervals with information from a central authority. You could call it a SG at that times :)

KitCarlson wrote:
I often did load flow programs

I liked to watch the variation of the power plant thermal efficiency variations (which varies with load greatly) with time of day. That is amazing how huge amounts of energy are wasted simply because there is no demand at the moment.

Quote:
It seems without careful design the result could be much like computer trading on the stock market.

I think that actually it is supposed to be a live energy stock exchange. The problem is that we live in the XXI-st century and nobody has invented the way to accumulate* or to transport** these goods efficiently yet. Can you imagine a stock exchange of such inconvenient goods?

KitCarlson wrote:
Enron.

Enron == greed, not grid.

KitCarlson wrote:
I think more about living in the woods, using a camp fire.

The efficiency of such process is appalling.

*with the price of accumulation at least comparable with current energy prices.
**within reasonable distance of at least several hundreds of kilometers.

No RSTDISBL, no fun!

Last Edited: Mon. Mar 26, 2012 - 09:27 PM
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What do they decide every 15 minutes? "I've got 10MW extra over here" "I need 20MW over here" "OK, flip that switch, send me a bill" That's a completely manual system. Would it be better to update every 5 min? Every 1 min? What I'm wondering is: You have a megawatt coming into a substation from a solar farm. Power is flowing 'out' from the substation. I guess this means the input voltage from the solar is a smidge higher than the output on the transmission lines to the other substations? Then a big cloud blows over and this gets all backwards in a couple of seconds. Can't wait 15 min to make phone call.

Imagecraft compiler user

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And would you believe coal can be moved long distance by train for less than losses in transmission lines.

I agree about greed, that has been around a long time.

Generators have governors and voltage regulators. Significant transients loads can lead to instability. It is my point that greed may exceed good engineering. The grid operation is quite complex, a huge active RLC circuit with complexity of mechanical inertia. The operation is non-intuitive to some, it takes much education and experience. To imagine a complete free automatic system, may end up being the "Terminator".

The campfire thing is my backup plan. Food tastes so good over an open fire. I do call for a burn permit. I don't quite get C02 control, plants need to breathe too. Plants need CO2 to make O2. I think the Green movement is political based, not based on good engineering or economics.

Nature rules, I have many downed trees after a tornado in 2009.

It all starts with a mental vision.

Last Edited: Mon. Mar 26, 2012 - 02:47 PM
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bobgardner wrote:
What do they decide every 15 minutes? "I've got 10MW extra over here" "I need 20MW over here" "OK, flip that switch, send me a bill" That's a completely manual system.

Yes, it is manual, but it is based on supply and demand law. That was how they did it. Via phone calls. The commands were targeting energy blocks, not power stations (each power station has several energy blocks, sometimes connected to independent transmission lines/voltages).

bobgardner wrote:
Would it be better to update every 5 min? Every 1 min?

The answer is easy: it would. Any closed loop process cannot degrade its quality shortening delays injected into the control loop. If not, delays would improve the quality, which is impossible in a deterministic world we live :)

bobgardner wrote:
What I'm wondering is:

Yes, this is a fast changing factor which is destabilizing the grid. The problem is the time constant of a PV is very short and their outputs are correlated (through clouds and the Sun).

A typical Power Plant (steam turbine) has some autonomy so it is stabilizing its output locally within several percent of its power. But its dynamics is really, really slow. The time constant of a typical thermal power station is of the order of hours. To restart it, you need days! What is more, it has a narrow range where its efficiency is high. Both, at lighter or higher loads thermal efficiency drops rapidly.

I guess you wanted to ask: "Will PVs decrease total CO2 emission, considering such slow reaction of conventional power plants?"
I doubt it. Not at locations where energy production is based on a fossil fuels and steam turbine power plants (that is - in most countries). You have to keep the nominal power available at all times in case of rapid changes of weather.
Not following the demand means blackout within seconds.

There are some types of power plants with shorter time constant, but these are expensive(in both $/W and $/J) and not that efficient(J/J).

KitCarlson wrote:
And would you believe coal can be moved long distance by train for less than losses in transmission lines.

And why by train? With water transport it could be more efficient at some (reasonable) distance - I think this method is used as an alternative in many places(instead of long transmission lines). Anyway, coal is much, much easier to market/manage than electrical energy. At least you can store(accumulate) it.

KitCarlson wrote:
The campfire thing is my backup plan.

And the horse?

No RSTDISBL, no fun!

Last Edited: Mon. Mar 26, 2012 - 02:57 PM
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Quote:
And would you believe coal can be moved long distance by train for less than losses in transmission lines.

You clearly have experience with the subject. Can you put some figures on this?

There are 132kV baby power lines going across my (ex) fields.
Alternatives might be underground cables.

There are obviously resistive losses in the aluminium / copper wires. And insulator losses on glass / plastic.

Presumably there is a cost benefit analysis done on each method. And if your claim is correct, the Didcot coal-fired power station that is miles away from sea-ports or coal fields has some sense !!

David.

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Kit Carlson,

"I think the American Indians had it figured out."

And I think the Amish will have the Last Laugh on all of us!

Many of these problems and strategic issues would be solved if someone would simply invent a lead-acid AC storage battery.

Whatever happened to the idea of using excess generated power to pump water into an uphill reservoir, then using that pressure head to regenerate the power at a later time of high demand?

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david.prentice wrote:
There are 132kV baby power lines going across my (ex) fields.

I think approximate calculations are quite easy in this case, just to understand the problem of sending this nasty product to the end-customer. All you need to know is the Ohms law, aluminium (and steel) stock prices, specific resistance. Find the approximate cost of 1km of such transmission line as a function of its losses. Simple as P=I*I*R. The stock energy and fuel prices are also available. From there one could easily find that at some distances there is no point to transport electrical energy because the transportation of the fossil fuels could be cheaper/more efficient. Usually made by sea/river, but sometimes by rail or even a pipe. Greatly depends on location, and what is available.

No RSTDISBL, no fun!

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Chuck-Rowst wrote:
Whatever happened to the idea of using excess generated power to pump water into an uphill reservoir, then using that pressure head to regenerate the power at a later time of high demand?

It is called:
http://en.wikipedia.org/wiki/Pum...
and, as you could imagine, natural occurrence of suitable conditions to build such thing is rare as hen's teeth.
What is more, it is only 75% efficient at best. There is one close to where I live, it is called "Porąbka-Żar", placed deep under the mountain, and it is open for visitors!
The only reason of its existence is:
Brutte wrote:
The time constant of a typical thermal power station is of the order of hours.

otherwise there would be no point transporting the energy there just to get back 75% of it 2 hours later.

Unfortunately nobody invented anything better.

Chuck-Rowst wrote:
Many of these problems and strategic issues would be solved if someone would simply invent a lead-acid AC storage battery.

It is not the problem of AC or DC energy accumulation, but the electrical energy in general. And the unit price of accumulating energy in secondary chemical cells is of different order of magnitude than in Pumped Storage Hydroelectricity.

No RSTDISBL, no fun!

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You wondered if I was wondering about CO2, and I am not worried about it at all. Right now the CO2 in the air is abour 0.03%. Almost unmeasureable. Plants will grow twice as fast if it gets to a couple percent. Humans dont need to worry until it gets to 5%. As for CO2 getting hot and staying hot for 100 years, all my observations show it gets hot for 12 hours when half the air is on the sun side, then it cools off 12 hrs later when the air is on the pluto side.

Imagecraft compiler user

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bobgardner wrote:
You wondered if I was wondering about CO2, and I am not worried about it at all.

CO2 is a main argument of "alternative energy sources" freaks. An increase of the efficiency of a grid is just another way to reduce CO2 production (or to decrease the cost of J, which means about the same, although not all agree in the proportions).
So the SG is a potential candidate which can/could have significant impact.

bobgardner wrote:
Plants will grow twice as fast if it gets to a couple percent.

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

It is the most important process on this small planet. Unfortunately we all share Earth so there is no way to divide it in two so that you could live on one side not worrying about CO2 at all with the other half occupied by some guys who simulate the photosynthesis process, the albedo, global temperature rise and population growth and eat their nails every time they see the output of this simulation.

It is about the cost of J. Including wars, Ohm's law losses, steel forged for windmills and the time wasted for washing dust away of PV modules.

No RSTDISBL, no fun!

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I think its about not being able to tolerate PV watts being injected from 1000s of grid tied homes because all the substations are designed to switch the transformer taps to maintain the load at 120V when the feeders sag. I dont think they can handle the load side voltage rising and causing the power to flow toward the generator. If the system was 50% PV, the generators would have to blow off steam every time the sun came out to keep from overspeeding.

Imagecraft compiler user

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bobgardner wrote:
I dont think they can handle the load side voltage rising and causing the power to flow toward the generator.

That is another problem a SG must handle - many producers, many consumers. The auto-transformer (or an AC/AC transformer in general) is a symmetrical device. There could be a problem with its controller and the stability, but this looks more like a software problem. So from my (poor) ee knowledge it seems it is doable.

But I am absolutely sure some sunny and windy Sunday of 2041 it will eventually happen that there are more joules produced than consumed somewhere. With a traditional grid - I have no idea what happens then. But for SG I suppose it is enough to send some broadcasts:

    "Consumers: We have sell-out of joules now! For every bought joule you get another one for free!" "Producers, I am sorry, the demand is quite low so you will not earn much today."

bobgardner wrote:
If the system was 50% PV, the generators would have to blow off steam every time the sun came out to keep from overspeeding.

I think all but smallest generators are synchronous so there is no risk of over-speeding your 60Hz.
But indeed as there are only a few methods to control demand nowadays and actually no way to store the energy - that is the only thing one can do in most cases.
But, as stated above, I do not think the Sun is the actual problem, but the fact that when it shines, you need to keep some reliable and fast backup power source all this time just in case some naughty clouds decided to pass by :)

No RSTDISBL, no fun!

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Seems to me aluminum plants could be used to stabilize the grid. Produce aluminum when there is an excess, electricity when there is a deficit. See e.g. http://web.mit.edu/newsoffice/2009/liquid-battery.html

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dak664 wrote:
Seems to me aluminum plants could be used to stabilize the grid.

Aluminum production requires huge amounts of electrical energy. If you want to run an aluminium plant, you need to own a power station as well. As close as possible.

I have seen a huge aluminum plant located at the end of one of the Norwegian fjords (cannot remind the name of the picturesque city - long tunnels through mountains to get there. Anyone knows the place? How many aluminum plants are there in Norway?). Guess what the plant was powered with?
Anyway, they transported the ore there and the aluminum back through fjords with ships.

KitCarlson wrote:
And would you believe coal can be moved long distance by train for less than losses in transmission lines.

That aluminum plant is another example of how difficult and expensive the transport of energy actually is.

cited article wrote:
Because the technology is being patented and could lead to very large-scale commercialization, Sadoway will not discuss the details of the materials being used.

Sounds interesting, but no details. This looks like a secondary chemical cell, and not an aluminum power plant(which was only an inspiration for the idea). Well, there are hundreds of designs of secondary cells. Some even older than 200 years now. None of them got even close to the idea of storing electrical energy at a price comparable with the value of the energy itself. That is, it is quite easy to charge a 100$ cell with an energy worth 1$, and getting back only 70% of it during discharge cycles. But it is harder to raise the funds for that.
Either price of the energy rises or the cells improve to make any of these ideas viable. I think Mr. Sadoway counts on both.

No RSTDISBL, no fun!

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Quote:
plants need to breathe too

Great line! Could I borrow it for a bumper sticker?

Tom Pappano
Tulsa, Oklahoma

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Quote:
Aluminum production requires huge amounts of electrical energy. If you want to run an aluminium plant, you need to own a power station as well. As close as possible.

Here in the US toward the end of the 19th century, this was one of the first uses for Niagra Falls. I think they also do pumped storage at Niagra.

Tom Pappano
Tulsa, Oklahoma

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I have been working all day so missed the posts. I have horses and farm animals.

I likely spend more time outdoors and living with nature than any green freak. Some of them think cows need diapers. *hit is good stuff, you just have to know how to step around it and use it.

Space is a great place for solar energy, so maybe we should get a better space program going.

It all starts with a mental vision.

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David,

About the coal. It has been about 35 years and I did not run the study about coal vs transmission losses, my boss told me. I do know at the time in a typical system generator to customer loss is about 7%.

The study was related to buying coal in Wyoming and shipping to central Iowa, about 1000 miles. I think there would have been other issues including stability to transfer 700 MW that far. No water to move coal that way. The train was the best.

And I ramble on.
Any smart grid control program needs to consider contingencies like loss of transmission lines or generators. The response need to be real-time. There are also spinning reserves and many other operating details mandated for reliable operation. The green energy complicates and provides little if any support, since they require backup. Investment or $KW is increased.

There is already considerable smart grid, to push things further, for political or greed means, may not yield the desired results.

It all starts with a mental vision.

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Here in Calif, long ago they started using high voltage DC transmissions lines. There's one I know of that is a million volts. I guess the losses converting to/from AC still make the DC scheme prudent.

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Chuck-Rowst wrote:
Many of these problems and strategic issues would be solved if someone would simply invent a lead-acid AC storage battery.
Aquion Energy, sodium-ion battery.
AC - The recently released silicon carbide rectifiers and JFETs will aid conversion efficiency.

"Dare to be naïve." - Buckminster Fuller

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bobgardner wrote:
You wondered if I was wondering about CO2, and I am not worried about it at all.
I am concerned (not worried, yet).
The Ocean's Carbon Balance, Humanity's Unexpected Impact by NASA.
The theory (or fact?) is this is causing the death of Mother Earth's oceans.
IIRC, the Orbiting Carbon Observatory was destroyed during a launch failure.

"Dare to be naïve." - Buckminster Fuller

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KitCarlson wrote:
I have horses and farm animals.

What I meant is that a campfire backup is not enough as it gives only heat and light - you need a mechanical energy as well. There are 1HP backup machines available, but their efficiency is really poor when compared to what we got used to use today.

KitCarlson wrote:
There is already considerable smart grid, to push things further, for political or greed means, may not yield the desired results.

You mean that this market can be controlled by some central authorities? I am sure it will be. The governments will love SG because this provides a lot of real time data and full control over this resource would become even easier than it is today. So for example with SG one can introduce completely new ways of "fair division of goods". For example this can be easily made based on time of day, your maximal power installed (kW), your consumption during peak hours (J) and many more - lots of opportunities for some new tax :)

stevech wrote:
Here in Calif, long ago they started using high voltage DC transmissions lines.

Ohm's law is ruthless. A transmission line which does not transport a thing 120 times each second has to be more expensive than the one which does it constantly.
stevech wrote:
There's one I know of that is a million volts.

Which one is it?
http://en.wikipedia.org/wiki/Lis...

I wonder what happens when it gets to the end customer. Who is willing to buy a 1e6eV electrons these days? Are there any customers? Perhaps some electrical smelters.. It is quite complicated to convert a DC to just about anything suitable at such voltages (when compared to AC/AC).

No RSTDISBL, no fun!

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Quote:

Whatever happened to the idea of using excess generated power to pump water into an uphill reservoir, then using that pressure head to regenerate the power at a later time of high demand?

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

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

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"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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Brutte,

The electric generation and distribution systems exists because it makes money for the companies that run them. You are right, there's a big governing equation for the overall business which involves Ohm's Law, The Law of Supply & Demand, the price of copper, aluminum, coal, oil, natural gas, plutonium and railroad car wheel bearings.

The bottom line is PROFIT, and maximizing it for those business tycoons holding their silk hats under the gushing firehose of dollars at the very end of the whole process. If an idea can't make more dollars gush out of that hose, it will never be implemented into the system. That's the bottom line - not electrical efficiency, not customer convenience, not conserving dwindling resources, none of these unless they make more dollars gush from the hose. See?

Therefore, if the "Smart Grid" can make more dollars gush from the hose, "THEY" will embrace, nurture & promote the Smart Grid vigorously and exhuberantly.

From this perspective I believe the Smart Grid is being widely anticipated and embraced because it will lead the way to Pay-as-You-Go Electrcity. Smart Meters located at customer premises will allow the electric companies to bill you daily or even hourly. Afterall without old-fashioned paper billing, the electric companies can tap your Pay-Pal account or electronic bank credit line daily or hourly. Can't Pay? We just turn off your electricity right at the Smart Meter, or sell you some KWHs on credit at a higher premium with penalty charges attached.

Ultimately, the power companies will use the Smart Grid to adopt the Cell Phone Billing Paradigm of placing the burden on the customer to predetermine how much electrciity he will need next month - Pay for it ahead of time, and use-it-or-lose it, just like cell phone minutes. Use more KWHs than you guessed, or more than were included in your "Basic Plan"? Ahhh, toooo bad! We'll just charge you the equivalent of a cell phone roaming charge - say, $3.00 per KWH. Remember the kid that ran up a $2,500 phone bill on his mom's cell phone? Wait'll you see those $25,000 electric bills!

I think I hear the Amish snickering already.

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How many years have you been cultivating that pessimistic cynical attitude?

Imagecraft compiler user

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Chuck-Rowst wrote:
That's the bottom line - not electrical efficiency, not customer convenience, not conserving dwindling resources

I totally agree. It must increase suppliers profits or reduce J cost for end customers to be brought into life.
Of course SG is not about the efficiency, CO2, convenience of customers or shareholders. I think you have misunderstood my remark about Enron. I believe a Smart Greed is a virtue in a capitalism, not a sin.

Anyway:

    -If a J from SG is more expensive than the one from traditional grid then customers do not buy it (if they have the choice). -If you are a supplier and can produce J cheaper than a competing company - you have more customers than others. And if it happens there are no competing suppliers in the neighborhood then you are a millionaire in no time, and it does not matter your technology is from Edison era.

Chuck-Rowst wrote:
Ultimately, the power companies will use the Smart Grid to adopt the Cell Phone Billing Paradigm

Yes, that is one of the choices. On Embedded World three weeks ago I had visited Freescale stand and they had a prepaid power meters designed for Latin America market. Those used some kind of RF technology to communicate with (your) regular phone (no, not bluetooth) and it performed encryption + authentication so you could preload your meter with some joules.. When the joules run out, it disconnected you from the grid. Cool. Actually this was not a SG meter but that meter was definitely smarter than the mechanical one I own currently.

No RSTDISBL, no fun!

Last Edited: Tue. Mar 27, 2012 - 04:16 PM
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Bob,

"pessimistic cynical attitude" ? Perhaps if you are strictly a consumer & sink for grid electrons, you likely would feel that way.

If, on the other hand (like myself), you were a shareholder in multiple energy sector Fortune 500 companies (including consumer electric suppliers ), you would be quite gleeful about the prospect of such a profitable situation unfolding in the near future.

I am overjoyed by the enthusiasm of my fellow EE types to invent the Smart Grid Future that will keep my Dom Perignon flowing plentifully for the next few decades!

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Quote:
What I meant is that a campfire backup is not enough as it gives only heat and light - you need a mechanical energy as well. There are 1HP backup machines available, but their efficiency is really poor when compared to what we got used to use today.

I am OK living in a primitive way. While most of my life has be spent working in technology. I would give it up, survival in nature leaves little time for technology. "Bear skins and stone knives", a quote from Spock, I think.

Government involvement in SG, oh my.

It all starts with a mental vision.

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Atmel has introduced an ARM-CM4 with an integrated power-line communication transceiver (PRIME PLC Modem).

http://www.atmel.com/Microsite/s...

Worth noting, it is a 120MHz device with 2MB of flash.
Smarter than expected..

No RSTDISBL, no fun!

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We call it "inter- connectivity".

The Romans called it "putting all of your eggs in one basket".

Go ahead and connect the power grid to the internet and call it "smart". Give it a Facebook Page too while you're at it. Then send out "updates" every day or so to the 300 million personel computers in America relying on some I-Phone App to keep their "green" refrigerator at the proper temperature so as to minimize carbon emissions.

Then tell me how "smart" you are when you come home and find all of your food at room temperature because your refrigerator's IP address was changed inadvertantly when the I-Phone App reset the freezer temperature for Daylight Savings Time.

I'll predict that if the Smart Grid actually becomes reality, back-up generator sales will skyrocket.

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dak664 wrote:
Seems to me aluminum plants could be used to stabilize the grid.

His TED Talk:
http://www.ted.com/talks/donald_...

No RSTDISBL, no fun!

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Our 5KW PV installation has been active now for just 100 days.

During the 80 day billing period first 11 days were PV input free.
At the end of the billing period we ended up with $189 in credit rather than the usual four to five hundred dollar bill.

In operation the PV inverter monitors presence and line condition and adjusts frequency /phase / voltage for appropriate generation conditions.

I am not sure the grid would become unstable if the cloud blocked off my contribution to the grid. In fact I would think the base load would remain fairly constant only line regulation would suffer if a major cloud were to hit the area.

In any case I suspect the distributed generation of PV sysytems is intended to minimise need for additional wires on top of powerpoles. The really expensive part of distribution network.

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Ignoramus,

May I ask the installed cost per KW?

It all starts with a mental vision.

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Kit,

The total installed cost ( panels, line inverter, installation ) was a tad over AUD 10500.
1AUD = USD1.04 presently

buy in rate of energy approx AUD 0.26 per KWh
sell rate approx AUD0.52 per KWh
So long as I arrange major consumption to take place outside daylight hours I stand to show at leas a positive zero balance.
Since I am not on town water all my water handling is energy dependent so watering the garden and washing machine use are done first thing of the morning before the panels start producing significant amounts of energy. Hot water is provided by a flow through gas boiler.
Cooking on gas stove most of the time.

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Quote:

buy in rate of energy approx AUD 0.26 per KWh
sell rate approx AUD0.52 per KWh

Enough diff to pay for a large accumulator-park? :D

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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so (..) and washing machine use are done first thing of the morning

What about a timer? Prepare the washing in the evening and set the timer so that it ends heating water before dawn.

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buy in rate of energy approx AUD 0.26 per KWh
sell rate approx AUD0.52 per KWh

Enough diff to pay for a large accumulator-park?

A coal-fired steam turbine generator would make you rich in no time at 0,5$/kWh. Alternatively you could use a simple gas generator to make the electrical energy (~20% thermal efficiency) and heat up the water in the boiler with the remaining 80% waste.

No RSTDISBL, no fun!

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Brutte,

Sadly legislation allows for only 5KW maximum generating capability.

This is to eliminate abuse of the subsidy scheme introduced to increase renewable energy sources.

Regarding gas fired generation ... there is a gas fuel cell which consumes natural gas to generate electricity and heat.

I am not familiar with efficiencies but it is something worth looking into.

The other option is wet steam cyclone ( www.cyclonepower.com ) engine based on the conventional Rankine cycle and yet there is a better engine designed by an Italian engineer which is a rotary steam engine and a bit more efficient than the reciprocating variant above.
Sorry no link to the Italian job.

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ignoramus wrote:
Regarding gas fired generation ... there is a gas fuel cell which consumes natural gas to generate electricity and heat.

I am not familiar with efficiencies but it is something worth looking into.

Bloom Energy, Benefits states about 60%.
Runs on methane (natural gas, biogas).
Recent information states they're looking at other sources of hydrogen.

"Dare to be naïve." - Buckminster Fuller

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gchapman wrote:
IIRC, the Orbiting Carbon Observatory was destroyed during a launch failure.
Its replacement has a planned launch for 2014-July-01 02:56:44 PDT from California's Vandenberg AFB.
The launch should be visible for quite some distance.
http://www.spaceweather.com/archive.php?view=1&day=30&month=06&year=2014
"LAUNCH ALERT:" near the page's top.

Rescheduled to July 2nd at 02:56:44 PDT.
http://spaceweather.com/archive.php?view=1&day=01&month=07&year=2014

"Dare to be naïve." - Buckminster Fuller