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...
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.
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
It seems without careful design the result could be much like computer trading on the stock market.
Enron.
I think more about living in the woods, using a camp fire.
*with the price of accumulation at least comparable with current energy prices.
**within reasonable distance of at least several hundreds of kilometers.
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.
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.
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:
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).
And would you believe coal can be moved long distance by train for less than losses in transmission lines.
The campfire thing is my backup plan.
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.
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?
There are 132kV baby power lines going across my (ex) fields.
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?
The time constant of a typical thermal power station is of the order of hours.
Unfortunately nobody invented anything better.
Many of these problems and strategic issues would be solved if someone would simply invent a lead-acid AC storage battery.
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.
You wondered if I was wondering about CO2, and I am not worried about it at all.
Plants will grow twice as fast if it gets to a couple percent.
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.
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.
I dont think they can handle the load side voltage rising and causing the power to flow toward the generator.
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:
If the system was 50% PV, the generators would have to blow off steam every time the sun came out to keep from overspeeding.
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
Seems to me aluminum plants could be used to stabilize the grid.
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.
And would you believe coal can be moved long distance by train for less than losses in transmission lines.
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.
plants need to breathe too
Great line! Could I borrow it for a bumper sticker?
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.
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.
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.
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.
Many of these problems and strategic issues would be solved if someone would simply invent a lead-acid AC storage battery.
You wondered if I was wondering about CO2, and I am not worried about it at all.
I have horses and farm animals.
There is already considerable smart grid, to push things further, for political or greed means, may not yield the desired results.
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 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).
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?
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.
How many years have you been cultivating that pessimistic cynical attitude?
That's the bottom line - not electrical efficiency, not customer convenience, not conserving dwindling resources
Anyway:
Ultimately, the power companies will use the Smart Grid to adopt the Cell Phone Billing Paradigm
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!
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.
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..
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.
Seems to me aluminum plants could be used to stabilize the grid.
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 $189 in credit rather than the usual four to five hundred dollar bill.
In operation the PV inverter monitors presence and line condition and adjusts frequency /phase / voltage for appropriate generation conditions.
I am not sure the grid would become unstable if the cloud blocked off my contribution to the grid. In fact I would think the base load would remain fairly constant only line regulation would suffer if a major cloud were to hit the area.
In any case I suspect the distributed generation of PV sysytems is intended to minimise need for additional wires on top of powerpoles. The really expensive part of distribution network.
Ignoramus,
May I ask the installed cost per KW?
Kit,
The total installed cost ( panels, line inverter, installation ) was a tad over AUD 10500.
1AUD = USD1.04 presently
buy in rate of energy approx AUD 0.26 per KWh
sell rate approx AUD0.52 per KWh
So long as I arrange major consumption to take place outside daylight hours I stand to show at leas a positive zero balance.
Since I am not on town water all my water handling is energy dependent so watering the garden and washing machine use are done first thing of the morning before the panels start producing significant amounts of energy. Hot water is provided by a flow through gas boiler.
Cooking on gas stove most of the time.
buy in rate of energy approx AUD 0.26 per KWh
sell rate approx AUD0.52 per KWh
so (..) and washing machine use are done first thing of the morning
Quote:buy in rate of energy approx AUD 0.26 per KWh
sell rate approx AUD0.52 per KWh
Enough diff to pay for a large accumulator-park?
A coal-fired steam turbine generator would make you rich in no time at 0,5$/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.
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.
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.
IIRC, the Orbiting Carbon Observatory was destroyed during a launch failure.
Rescheduled to July 2nd at 02:56:44 PDT.
http://spaceweather.com/archive.php?view=1&day=01&month=07&year=2014
